git.ipfire.org Git - thirdparty/linux.git/log

selftests/mm: move hwpoison setup into run_test() and silence modprobe output for memory-failure category

run_vmtests.sh contains special handling to ensure the hwpoison_inject
module is available for the memory-failure tests.  This logic was
implemented outside of run_test(), making the setup category-specific but
managed globally.

Move the hwpoison_inject handling into run_test() and restrict it
to the memory-failure category so that:
1. the module is checked and loaded only when memory-failure tests run,
2. the test is skipped if the module or the debugfs interface
(/sys/kernel/debug/hwpoison/) is not available.
3. the module is unloaded after the test if it was loaded by the script.

This localizes category-specific setup and makes the test flow
consistent with other per-category preparations.

While updating this logic, fix the module availability check.
The script previously used:

        modprobe -R hwpoison_inject

The -R option prints the resolved module name to stdout, causing every
run to print:

        hwpoison_inject

in the test output, even when no action is required, introducing
unnecessary noise.

Replace this with:

        modprobe -n hwpoison_inject

which verifies that the module is loadable without producing output,
keeping the selftest logs clean and consistent.

Also, ensure that skipped tests do not override a previously recorded
failure.  A skipped test currently sets exitcode to ksft_skip even if a
prior test has failed, which can mask failures in the final exit status.
Update the logic to only set exitcode to ksft_skip when no failure has
been recorded.

Link: https://lore.kernel.org/93441f34f7ef5add47d1a130d03daa79e21b5050.1779296493.git.sayalip@linux.ibm.com
Fixes: ff4ef2fbd101 ("selftests/mm: add memory failure anonymous page test")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: skip uffd-stress test when nr_pages_per_cpu is zero

uffd-stress currently fails when the computed nr_pages_per_cpu evaluates
to zero:

nr_pages_per_cpu = bytes / page_size / nr_parallel

This can occur on systems with large hugepage sizes (e.g. 1GB) and a high
number of CPUs, where the total allocated memory is sufficient overall but
not enough to provide at least one page per cpu.

In such cases, the failure is due to insufficient test resources rather
than incorrect kernel behaviour. Update the test to treat this condition
as a test skip instead of reporting an error.

[sayalip@linux.ibm.com: use ksft_exit_skip() instead of KSFT_SKIP]
Link: https://lore.kernel.org/88202b56-1dc5-43e2-9d1f-a0823a9531f0@linux.ibm.com
Link: https://lore.kernel.org/0707e9a0f1b3dd904c4a069b91db317f9c160faa.1779296493.git.sayalip@linux.ibm.com
Fixes: db0f1c138f18 ("selftests/mm: print some details when uffd-stress gets bad params")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: skip uffd-wp-mremap if UFFD write-protect is unsupported

The uffd-wp-mremap test requires the UFFD_FEATURE_PAGEFAULT_FLAG_WP
capability.  On systems where userfaultfd write-protect is not supported,
uffd_register() fails and the test reports failures.

Check for the required feature at startup and skip the test when the
UFFD_FEATURE_PAGEFAULT_FLAG_WP capability is not present, preventing false
failures on unsupported configurations.

Before patch:
running ./uffd-wp-mremap
------------------------
  [INFO] detected THP size: 256 KiB
  [INFO] detected THP size: 512 KiB
  [INFO] detected THP size: 1024 KiB
  [INFO] detected THP size: 2048 KiB
  [INFO] detected hugetlb page size: 2048 KiB
  [INFO] detected hugetlb page size: 1048576 KiB
1..24
  [RUN] test_one_folio(size=65536, private=false, swapout=false,
  hugetlb=false)
not ok 1 uffd_register() failed
  [RUN] test_one_folio(size=65536, private=true, swapout=false,
  hugetlb=false)
not ok 2 uffd_register() failed
  [RUN] test_one_folio(size=65536, private=false, swapout=true,
  hugetlb=false)
not ok 3 uffd_register() failed
  [RUN] test_one_folio(size=65536, private=true, swapout=true,
  hugetlb=false)
not ok 4 uffd_register() failed
  [RUN] test_one_folio(size=262144, private=false, swapout=false,
  hugetlb=false)
not ok 5 uffd_register() failed
  [RUN] test_one_folio(size=524288, private=false, swapout=false,
  hugetlb=false)
not ok 6 uffd_register() failed
.
.
.
Bail out! 24 out of 24 tests failed
  Totals: pass:0 fail:24 xfail:0 xpass:0 skip:0 error:0
[FAIL]
not ok 1 uffd-wp-mremap # exit=1

After patch:
running ./uffd-wp-mremap
------------------------
1..0 # SKIP uffd-wp feature not supported
[SKIP]
ok 1 uffd-wp-mremap # SKIP

Link: https://lore.kernel.org/c3c5af76d71d5f4446f773f4de94882efc33ebe4.1779296493.git.sayalip@linux.ibm.com
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: ensure destination is hugetlb-backed in hugetlb-mremap

The hugetlb-mremap selftest reserves the destination address using a
anonymous base-page mapping before calling mremap() with MREMAP_FIXED,
while the source region is hugetlb-backed.

When remapping a hugetlb mapping into a base-page VMA may fail with:

mremap: Device or resource busy

This is observed on powerpc hash MMU systems where slice constraints and
page size incompatibilities prevent the remap.

Ensure the destination region is created using MAP_HUGETLB so that both
source and destination VMAs are hugetlb-backed and compatible.

Update the FLAGS macro to include MAP_HUGETLB | MAP_SHARED so that both
mappings are hugetlb-backed and compatible. Also use the macro for the
mmap() calls to avoid repeating the flag combination.

This ensures the test reliably exercises hugetlb mremap instead of failing
due to VMA type mismatch.

Link: https://lore.kernel.org/367644df45c65098f23e3945c6a80f4b8a8964a6.1779296493.git.sayalip@linux.ibm.com
Fixes: 12b613206474 ("mm, hugepages: add hugetlb vma mremap() test")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftest/mm: register existing mapping with userfaultfd in hugetlb-mremap

Previously, register_region_with_uffd() created a new anonymous mapping
and overwrote the address supplied by the caller before registering the
range with userfaultfd.

As a result, userfaultfd was applied to an unrelated anonymous mapping
instead of the hugetlb region used by the test.

Remove the extra mmap() and register the caller-provided address range
directly using UFFDIO_REGISTER_MODE_MISSING, so that faults are generated
for the hugetlb mapping used by the test.

This ensures userfaultfd operates on the actual hugetlb test region and
validates the expected fault handling.

Before patch:
running ./hugetlb-mremap
-------------------------
TAP version 13
1..1
  Map haddr: Returned address is 0x7eaa40000000
  Map daddr: Returned address is 0x7daa40000000
  Map vaddr: Returned address is 0x7faa40000000
  Address returned by mmap() = 0x7fff9d000000
  Mremap: Returned address is 0x7faa40000000
  First hex is 0
  First hex is 3020100
ok 1 Read same data
Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
[PASS]
ok 1 hugetlb-mremap

After patch:
running ./hugetb-mremap
-------------------------
TAP version 13
1..1
  Map haddr: Returned address is 0x7eaa40000000
  Map daddr: Returned address is 0x7daa40000000
  Map vaddr: Returned address is 0x7faa40000000
  Registered memory at address 0x7eaa40000000 with userfaultfd
  Mremap: Returned address is 0x7faa40000000
  First hex is 0
  First hex is 3020100
ok 1 Read same data
Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
[PASS]
ok 1 hugetlb-mremap

Link: https://lore.kernel.org/13845da872ed174316173e8996dbb5f181994017.1779296493.git.sayalip@linux.ibm.com
Fixes: 12b613206474 ("mm, hugepages: add hugetlb vma mremap() test")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: free dynamically allocated PMD-sized buffers in split_huge_page_test

Dynamically allocated buffers of PMD size for file-backed THP operations
(file_buf1 and file_buf2) were not freed on the success path and some
failure paths. Since the function is called repeatedly in a loop for each
split order, this can cause significant memory leaks.

On architectures with large PMD sizes, repeated leaks could exhaust system
memory and trigger the OOM killer during test execution.

Ensure all allocated buffers are freed to maintain stable repeated test
runs.

Link: https://lore.kernel.org/060c673b376bbeeed2b1fb1d48a825e846654191.1779296493.git.sayalip@linux.ibm.com
Fixes: 035a112e5fd5 ("selftests/mm: make file-backed THP split work by writing PMD size data")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: size tmpfs according to PMD page size in split_huge_page_test

The split_file_backed_thp() test mounts a tmpfs with a fixed size of "4m".
This works on systems with smaller PMD page sizes, but fails on
configurations where the PMD huge page size is larger (e.g.  16MB).

On such systems, the fixed 4MB tmpfs is insufficient to allocate even a
single PMD-sized THP, causing the test to fail.

Fix this by sizing the tmpfs dynamically based on the runtime
pmd_pagesize, allocating space for two PMD-sized pages.

Before patch:
  running ./split_huge_page_test /tmp/xfs_dir_YTrI5E
  --------------------------------------------------
  TAP version 13
  1..55
  ok 1 Split zero filled huge pages successful
  ok 2 Split huge pages to order 0 successful
  ok 3 Split huge pages to order 2 successful
  ok 4 Split huge pages to order 3 successful
  ok 5 Split huge pages to order 4 successful
  ok 6 Split huge pages to order 5 successful
  ok 7 Split huge pages to order 6 successful
  ok 8 Split huge pages to order 7 successful
  ok 9 Split PTE-mapped huge pages successful
   Please enable pr_debug in split_huge_pages_in_file() for more info.
   Failed to write data to testing file: Success (0)
  Bail out! Error occurred
   Planned tests != run tests (55 != 9)
   Totals: pass:9 fail:0 xfail:0 xpass:0 skip:0 error:0
[FAIL]

After patch:
  running ./split_huge_page_test /tmp/xfs_dir_bMvj6o
  --------------------------------------------------
  TAP version 13
  1..55
  ok 1 Split zero filled huge pages successful
  ok 2 Split huge pages to order 0 successful
  ok 3 Split huge pages to order 2 successful
  ok 4 Split huge pages to order 3 successful
  ok 5 Split huge pages to order 4 successful
  ok 6 Split huge pages to order 5 successful
  ok 7 Split huge pages to order 6 successful
  ok 8 Split huge pages to order 7 successful
  ok 9 Split PTE-mapped huge pages successful
   Please enable pr_debug in split_huge_pages_in_file() for more info.
   Please check dmesg for more information
  ok 10 File-backed THP split to order 0 test done
   Please enable pr_debug in split_huge_pages_in_file() for more info.
   Please check dmesg for more information
  ok 11 File-backed THP split to order 1 test done
   Please enable pr_debug in split_huge_pages_in_file() for more info.
   Please check dmesg for more information
  ok 12 File-backed THP split to order 2 test done
...
  ok 55 Split PMD-mapped pagecache folio to order 7 at
    in-folio offset 128 passed
   Totals: pass:55 fail:0 xfail:0 xpass:0 skip:0 error:0
   [PASS]
ok 1 split_huge_page_test /tmp/xfs_dir_bMvj6o

Link: https://lore.kernel.org/33e1bc10753fe82d1217613d8cd496020778cf2b.1779296493.git.sayalip@linux.ibm.com
Fixes: fbe37501b252 ("mm: huge_memory: debugfs for file-backed THP split")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: fix cgroup task placement and drop memory.current checks in hugetlb_reparenting_test.sh

The test currently moves the calling shell ($$) into the target cgroup
before executing write_to_hugetlbfs.  This results in the shell and any
intermediate allocations being charged to the cgroup, introducing noise
and nondeterminism in accounting.  It also requires moving the shell back
to the root cgroup after execution.

Spawn a helper process that joins the target cgroup and exec()'s
write_to_hugetlbfs.  This ensures that only the workload is accounted to
the cgroup and avoids unintended charging from the shell.

The test currently validates both hugetlb usage and memory.current.
However, memory.current includes internal memcg allocations and per-CPU
batched accounting (MEMCG_CHARGE_BATCH), which are not synchronized and
can vary across systems, leading to non-deterministic results.

Since hugetlb memory is accounted via hugetlb.<size>.current,
memory.current is not a reliable indicator here.  Drop memory.current
checks and rely only on hugetlb controller statistics for stable and
accurate validation.

Link: https://lore.kernel.org/fb57491ba83cb0a499c72922e1579b61bee514db.1779296493.git.sayalip@linux.ibm.com
Fixes: 29750f71a9b4 ("hugetlb_cgroup: add hugetlb_cgroup reservation tests")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: fix hugetlb pathname construction in hugetlb_reparenting_test.sh

The hugetlb_reparenting_test.sh script constructs hugetlb cgroup memory
interface file names based on the configured huge page size. The script
formats the size only in MB units, which causes mismatches on systems
using larger huge pages where the kernel exposes normalized units (e.g.
"1GB" instead of "1024MB").

As a result, the test fails to locate the corresponding cgroup files when
1GB huge pages are configured.

Update the script to detect the huge page size and select the appropriate
unit (MB or GB) so that the constructed paths match the kernel's hugetlb
controller naming.

Also print an explicit "Fail" message when a test failure occurs to
improve result visibility.

Link: https://lore.kernel.org/837ce751965c93f74c95d89587debf1e93281364.1779296493.git.sayalip@linux.ibm.com
Fixes: e487a5d513cb ("selftest/mm: make hugetlb_reparenting_test tolerant to async reparenting")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: restore default nr_hugepages value via exit trap in hugetlb_reparenting_test.sh

The test modifies nr_hugepages during execution and restores it from
cleanup() and again reconfigure it setup, which is invoked multiple times
across test flow. This can lead to repeated allocation/freeing of
hugepages.

With set -e, failures in cleanup (e.g., rmdir/umount) can also cause early
exit before restoring the original value at the end.

Move restoration of the original nr_hugepages value to a trap handler
registered for EXIT, INT, and TERM signals so it is always restored on all
exit paths. This also avoids unnecessary allocation churn across repeated
cleanup/setup cycles.

Link: https://lore.kernel.org/29db637c3c6ba6c168f6b33f59f059a0b39c35c8.1779296493.git.sayalip@linux.ibm.com
Fixes: 585a9145886a ("selftests/mm: restore default nr_hugepages value during cleanup in hugetlb_reparenting_test.sh")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: fix hugetlb pathname construction in charge_reserved_hugetlb.sh

The charge_reserved_hugetlb.sh script assumes hugetlb cgroup memory
interface file names use the "<size>MB" format
(e.g. hugetlb.1024MB.current).
This assumption breaks on systems with larger huge pages such as 1GB,
where the kernel exposes normalized units:
    hugetlb.1GB.current
    hugetlb.1GB.max
    hugetlb.1GB.rsvd.max
    ...

As a result, the script attempts to access files like
hugetlb.1024MB.current, which do not exist when the kernel reports the
size in GB.

Normalize the huge page size and construct the pathname using the
appropriate unit (MB or GB), matching the hugetlb controller naming.

Link: https://lore.kernel.org/04b6b49e4a2acf46319f627caf82b09e6dc1ad7f.1779296493.git.sayalip@linux.ibm.com
Fixes: 209376ed2a84 ("selftests/vm: make charge_reserved_hugetlb.sh work with existing cgroup setting")
Fixes: 29750f71a9b4 ("hugetlb_cgroup: add hugetlb_cgroup reservation tests")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: restore default nr_hugepages value via exit trap in charge_reserved_hugetlb.sh

Patch series "selftests/mm: fix failures and robustness improvements", v7.

Powerpc systems with a 64K base page size exposed several issues while
running mm selftests. Some tests assume specific hugetlb configurations,
use incorrect interfaces, or fail instead of skipping when the required
kernel features are not available.

This series fixes these issues and improves test robustness.

This patch (of 13):

cleanup() resets nr_hugepages to 0 on every invocation, while the test
reconfigures it again in the next iteration. This leads to repeated
allocation and freeing of large numbers of hugepages, especially when the
original value is high.

Additionally, with set -e, failures in earlier cleanup steps (e.g., rmdir
or umount returning EBUSY while background activity is still ongoing) can
cause the script to exit before restoring the original value, leaving the
system in a modified state.

Introduce a trap on EXIT, INT, and TERM to restore the original
nr_hugepages value once at script termination. This avoids unnecessary
allocation churn and ensures the original value is reliably restored on
all exit paths.

Link: https://lore.kernel.org/cover.1779296493.git.sayalip@linux.ibm.com
Link: https://lore.kernel.org/5b8fbb29cd6ceffe6752e0af104f60cec072aa10.1779296493.git.sayalip@linux.ibm.com
Fixes: 7d695b1c3695 ("selftests/mm: save and restore nr_hugepages value")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: fix incorrect mmap() error handling with NULL instead of MAP_FAILED

mmap() returns MAP_FAILED, which is defined as (void *)-1, on error, not
NULL. Several selftests incorrectly check the return value of mmap()
using !ptr or ptr == NULL, which would erroneously treat MAP_FAILED as a
valid pointer since MAP_FAILED is non-zero and non-NULL. This can lead to
segfaults when mmap() actually fails under memory pressure.

Link: https://lore.kernel.org/20260513025223.592766-1-lihongfu@kylinos.cn
Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: avoid underflow in madvise_collapse for sub-PMD MADV_COLLAPSE

madvise_collapse() computes the THP-aligned window:

    hstart = ALIGN(start, HPAGE_PMD_SIZE); /* round up */
    hend = ALIGN_DOWN(end, HPAGE_PMD_SIZE); /* round down */

The following case will cause hstart > hend, and result in underflow in
the return statement, avoid it by returning zero early when hstart > hend.
The return value is due to input is valid to madvise(), and there is
nothing to collapse.

    madvise(PMD-aligned + PAGE_SIZE, PAGE_SIZE, MADV_COLLAPSE);

In addition, kmalloc_obj(), mmgrab() and lru_add_drain_all() are
unnecessary when hstart == hend, so skip these operations by returning
early too.

Link: https://lore.kernel.org/20260513055428.1664898-1-chenwandun@lixiang.com
Signed-off-by: Chen Wandun <chenwandun@lixiang.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: run_vmtests.sh: drop detection and setup of HugeTLB

All the tests that use HugeTLB can detect and setup HugeTLB pages on their
own.

Drop detection and setup of HugeTLB from run_vmtests.sh.

Link: https://lore.kernel.org/20260511162840.375890-56-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: run_vmtests.sh: free memory if available memory is low

Currently when running THP and HugeTLB tests, if HAVE_HUGEPAGES is set
run_test() drops caches, compacts memory and runs the test. But if
HAVE_HUGEPAGES is not set it skips the tests entirely, even if THP tests
have nothing to do with HAVE_HUGEPAGES.

Replace the check if HAVE_HUGEPAGES is set with a check of how much memory
is available. If there is less than 256 MB of available memory, drop
caches and run compaction and then continue to run a test regardless of
HAVE_HUGEPAGES value.

Link: https://lore.kernel.org/20260511162840.375890-55-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: va_high_addr_switch.sh: drop huge pages setup

Since va_high_addr_switch takes care of setting up huge pages, there is no
need to set them up in the va_high_addr_switch.sh wrapper script.

Link: https://lore.kernel.org/20260511162840.375890-54-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: va_high_addr_switch: add setup of HugeTLB pages

va_high_addr_switch skips HugeTLB tests if there are no free huge pages
prepared by a wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-53-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: uffd-wp-mremap: add setup of HugeTLB pages

uffd-wp-remap skips HugeTLB tests if there are no free huge pages prepared
by a wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-52-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: uffd-unit-tests: add setup of HugeTLB pages

uffd-unit-tests skips HugeTLB tests if there are no free huge pages
prepared by a wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Replace exit() calls with _exit() to avoid restoring HugeTLB settings in
the middle of test.

Link: https://lore.kernel.org/20260511162840.375890-51-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: uffd-stress: use hugetlb_save and alloc huge pages

uffd-stress skips HugeTLB tests if there are no free huge pages prepared
by a wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-50-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: thuge-gen: add setup of HugeTLB pages

thuge-gen skips tests if there are no free huge pages prepared by a
wrapper script and shm liimts in proc are too low.

Replace custom detection of huge pages with the library functions and add
setup of HugeTLB pages and shm limits to the test and make sure that the
original settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-49-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: protection_keys: use library code for HugeTLB setup

protection_keys open codes setup of HugeTLB pages.

Replace it with the library functions from hugepage_setup.

Replace exit() calls with _exit() to avoid restoring HugeTLB settings in
the middle of test.

Link: https://lore.kernel.org/20260511162840.375890-48-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: pagemap_ioctl: add setup of HugeTLB pages

pagemap-ioctl skips HugeTLB tests if there are no free huge pages prepared
by a wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-47-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: migration: add setup of HugeTLB pages

migration skips HugeTLB tests if there are no free huge pages prepared by
a wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Since kselftest_harness runs fixture setup and the tests in child
processes, use HUGETLB_SETUP_DEFAULT_PAGES() that defines a constructor
that runs in the main process and add verification that there are enough
free huge pages to the tests that use them.

Reset signal handlers to defaults in FIXTURE_SETUP() so that sending
SIGTERM and SIGHUP during the tests won't cause restoration of HugeTLB
settings.

Link: https://lore.kernel.org/20260511162840.375890-46-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugetlb-vmemmap: add setup of HugeTLB pages

hugetlb-vmemmap test fails if there are no free huge pages prepared by a
wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-45-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugetlb-soft-offline: add setup of HugeTLB pages

hugetlb-soft-offline test uses open coded access to /proc to determine
availability of huge pages and fails if there are no enough free huget
pages..

Replace open coded access to /proc with hugepage helpers and add setup of
HugeTLB pages to the test and make sure that the original settings are
restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-44-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugetlb-shm: add setup of HugeTLB pages

hugetlb-shm test fails if there are no free huge pages prepared by a
wrapper script and shm liimts in proc are too low.

Add setup of HugeTLB pages and shm limits to the test and make sure that
the original settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-43-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugetlb-mremap: add setup of HugeTLB pages

hugetlb-mremap test fails if there are no free huge pages prepared by a
wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-42-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugetlb-mmap: add setup of HugeTLB pages

hugetlb-mmap test fails if there are no free huge pages prepared by a
wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-41-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugetlb_madv_vs_map: add setup of HugeTLB pages

hugetlb_madv_vs_map test skips testing if there are no free huge pages
prepared by a wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-40-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugetlb-madvise: add setup of HugeTLB pages

hugetlb-madvise test skips testing if there are no free huge pages
prepared by a wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-39-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugetlb_fault_after_madv: add setup of HugeTLB pages

hugetlb_fault_after_madv test skips testing if there are no free huge
pages prepared by a wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-38-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugepage_dio: add setup of HugeTLB pages

hugepage_dio test fails if there are no free huge pages prepared by a
wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-37-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hmm-tests: add setup of HugeTLB pages

hmm-tests skips HugeTLB tests if there are no free huge pages prepared by
a wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Since kselftest_harness runs fixture setup and the tests in child
processes, use HUGETLB_SETUP_DEFAULT_PAGES() that defines a constructor
that runs in the main process and add verification that there are enough
free huge pages to the tests that use them.

Replace exit() calls with _exit() to avoid restoring HugeTLB settings in
the middle of test and use SIGKILL to kill a child process in
hmm_cow_in_device test to avoid interference with signal handlers in
hugepage_restore_settings().

Link: https://lore.kernel.org/20260511162840.375890-36-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: gup_test: add setup of HugeTLB pages

gup_test fails to run HugeTLB tests if there are no free huge pages
prepared by a wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-35-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: gup_longterm: add setup of HugeTLB pages

gup_longterm tests skips HugeTLB tests if there are no free huge pages
prepared by a wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-34-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: cow: add setup of HugeTLB pages

cow tests skips HugeTLB tests if there are no free huge pages prepared by
a wrapper script.

Add setup of HugeTLB pages to the test and make sure that the original
settings are restored on the test exit.

Link: https://lore.kernel.org/20260511162840.375890-33-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: compaction_test: use HugeTLB helpers ...

... instead of open coded access of HugeTLB parameters via /proc.

Link: https://lore.kernel.org/20260511162840.375890-32-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: vm_util: add helpers to set and restore shm limits

hugetlb-shm and thuge-gen tests require that limits defined by
/proc/sys/kernel/{shmmax,shmall} should be higher than certain values.

Add helpers that allow setting these limits and restoring their settings
on a test exit.

They will be used later in hugetlb-shm and thuge-gen.

Link: https://lore.kernel.org/20260511162840.375890-31-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: move read_file(), read_num() and write_num() to vm_util

These are useful helpers for writing and reading sysfs and proc files.

Make them available to the tests that don't use thp_settings.

While on it make write_num() use "%lu" instead of "%ld" to match 'unsigned
long num' argument type.

Link: https://lore.kernel.org/20260511162840.375890-30-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugepage_settings: add APIs for HugeTLB setup and teardown

A lot of tests require free HugeTLB pages. Some need just a few default
huge pages, some need a certain amount of memory available as HugeTLB, and
some just skip lots of tests if huge pages of all supported sizes are not
available.

This all resulted in a huge mess in run_vmtests.sh that sets up some huge
pages, adjusts them later and restores some of the settings if the stars
align.

Add APIs that allow saving the state of HugeTLB and setting up the desired
amount of HugeTLB pages.

Saving the state also registers atexit() callback and signal handler that
will ensure restoration of HugeTLB state.

Since many tests use both HugeTLB and THP, the atexit() callbacks and
signal handler are restoring both.

For kselftest_harness tests that run fixture setups and test in child
processes add a constructor that will save and restore settings in the
main process.

Link: https://lore.kernel.org/20260511162840.375890-29-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Reviewed-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugepage_settings: rename and rework get_free_hugepages()

... to hugetlb_free_default_pages() for consistency with
hugetlb_nr_default_pages().

Make hugetlb_free_default_pages() use hugetlb_sysfs_path() helper instead
of parsing /proc/meminfo.

Link: https://lore.kernel.org/20260511162840.375890-28-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugepage_settings: add APIs to get and set nr_hugepages

Add APIs that allow reading and writing of

/sys/kernel/mm/hugepages/hugepages-NkB/nr_hugepages

to detect and change the amount of HugeTLB pages of different sizes.

Link: https://lore.kernel.org/20260511162840.375890-27-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugepage_settings: use unsigned long in detect_hugetlb_page_size

... instead of size_t to avoid type mismatch in 32 and 64 bit builds.

Link: https://lore.kernel.org/20260511162840.375890-26-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: move HugeTLB helpers to hugepage_settings

Move library functions that abstract HugeTLB /proc and /sysfs access from
vm_util to hugepage_settings.

This will help creating common helpers that save and restore HugeTLB and
THP settings.

Link: https://lore.kernel.org/20260511162840.375890-25-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: rename thp_settings.[ch] to hugepage_settings.[ch]

... for upcoming addition of HugeTLB helpers.

Link: https://lore.kernel.org/20260511162840.375890-24-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: add atexit() and signal handlers to thp_settings

khugepaged registers atexit() and signal handlers that ensure that THP
settings are restored regardless of how the test exited.

Make these handlers available for all users of thp_settings.

The call to thp_save_settings() installs thp_restore_settings as the
atexit() callback and makes sure that signals that kill a process would
still call exit() and atexit() callback.

Update child process in khugepaged tests using thp_settings to use _exit()
instead of exit() to avoid altering THP settings in the middle of a test.

Remove redundant THP cleanup from folio_split_race_test.c.

Link: https://lore.kernel.org/20260511162840.375890-23-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: va_high_addr_switch: use kselftest framework

Convert va_high_addr_switch test to use kselftest framework for reporting
and tracking successful and failing runs.

Link: https://lore.kernel.org/20260511162840.375890-22-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: uffd-unit-tests: use kselftest framework

Convert uffd-unit-tests to use kselftest framework for reporting and
tracking successful and failing runs.

Link: https://lore.kernel.org/20260511162840.375890-21-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: uffd-stress: use kselftest framework

Convert uffd-stress test to use kselftest framework for reporting and
tracking successful and failing runs.

Link: https://lore.kernel.org/20260511162840.375890-20-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: uffd-common: use kselftest framework

Update err() and errexit() to use ksft_print_msg() and ksft_exit_fail().

This is preparatory change required to update userfaulfd tests to use
kselftest framework.

Link: https://lore.kernel.org/20260511162840.375890-19-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Luiz Capitulino <luizcap@redhat.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: protection_keys: use kselftest framework

Convert protection_keys test to use kselftest framework for reporting and
tracking successful and failing runs.

Adjust dprintf0() printouts to use "#" in the beginning of the line for
TAP compatibility.

Link: https://lore.kernel.org/20260511162840.375890-18-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: protection_keys: use descriptive test names in the output

Replace the numeric test index in TAP output with the actual test function
name.

Use a structure containing function pointer and its name rather than only
the function pointer in the pkey_tests array.

Link: https://lore.kernel.org/20260511162840.375890-17-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: ksm_tests: use kselftest framework

Convert ksm_tests to use kselftest framework for reporting and tracking
successful and failing runs.

Link: https://lore.kernel.org/20260511162840.375890-16-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: khugepaged: use kselftest framework

Convert khugepaged tests to use kselftest framework for reporting and
tracking successful and failing runs.

The conversion is mostly about replacing printf()/perror() + exit() pairs
with their ksft_ counterparts.

The nice colored success and failure indications are left intact.

Replace the progress report in collapse_compound_extreme() with a single
ksft_print_msg() to avoid headache with formatting and make the test
output more concise.

[rppt@kernel.org: make the output TAP-compatible]
[ziy@nvidia.com: update for "Remove CONFIG_READ_ONLY_THP_FOR_FS and enable file THP for writable files", v6]
https://lore.kernel.org/20260517135416.1434539-1-ziy@nvidia.com
Link: https://lore.kernel.org/20260511162840.375890-15-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Li Wang <li.wang@linux.dev>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: khugepaged: group tests in an array

Currently khugepaged decides if a test can run using TEST() macro that
checks what mem_ops and collapse_context are set by the command line
arguments.

For better compatibility with ksefltest framework, add an array of 'struct
test_case's and redefine TEST() macro to conditionally add enabled tests
to that array.

Then execute the enabled test by looping the test_case's array.

Link: https://lore.kernel.org/20260511162840.375890-14-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugetlb-read-hwpoison: use kselftest framework

Convert hugetlb-read-hwpoison test to use kselftest framework for
reporting and tracking successful and failing runs.

Link: https://lore.kernel.org/20260511162840.375890-13-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Li Wang <li.wang@linux.dev>
Reviewed-by: Li Wang <li.wang@linux.dev>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugetlb_madv_vs_map: use kselftest framework

Convert hugetlb_madv_vs_map test to use kselftest framework for reporting
and tracking successful and failing runs.

Link: https://lore.kernel.org/20260511162840.375890-12-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugetlb-madvise: use kselftest framework

Convert hugetlb-madvise test to use kselftest framework for reporting and
tracking successful and failing runs.

While on it fix the check for base page size detection to actually use
base_page_size.

Link: https://lore.kernel.org/20260511162840.375890-11-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugetlb-vmemmap: use kselftest framework

Convert hugetlb-vmemmap test to use kselftest framework for reporting and
tracking successful and failing runs.

Link: https://lore.kernel.org/20260511162840.375890-10-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugetlb-shm: use kselftest framework

Convert hugetlb-shm test to use kselftest framework for reporting and
tracking successful and failing runs.

Link: https://lore.kernel.org/20260511162840.375890-9-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: rename hugepage-* tests to hugetlb-*

hugepage could mean both THP and HugeTLB these days.

Rename hugepage-* tests for HugeTLB to hugetlb-* to avoid confusion.

Make sure that Makefile update keeps alphabetical ordering of the
TEST_GEN_FILES entries.

Keep old binary names in .gitignore because Linus prefers it this way.

Link: https://lore.kernel.org/20260511162840.375890-8-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Reviewed-by: Li Wang <li.wang@linux.dev>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: merge map_hugetlb into hugepage-mmap

Both tests create a hugettlb mapping, fill it with data and verify the
data, the only difference is that one uses file-backed memory and another
one uses anonymous memory.

Merge both tests into a single file.

Link: https://lore.kernel.org/20260511162840.375890-7-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Luiz Capitulino <luizcap@redhat.com>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: run_vmtests.sh: don't gate THP and KSM tests on HAVE_HUGEPAGES

HAVE_HUGEPAGES indicates availability of free HugeTLB pages. It should
not be used to gate KSM test that merges transparent huge pages or
split_huge_page_test.

Remove check for HAVE_HUGEPAGES when running these tests.

Link: https://lore.kernel.org/20260511162840.375890-6-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Li Wang <li.wang@linux.dev>
Reviewed-by: Li Wang <li.wang@linux.dev>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: migration: properly cleanup fork()ed processes

Several migration test use fork() to create worker processes. These
processes are later killed, but nothing collects their exit status and
they remain as zombies in the system.

Add a helper function that kills the worker processes, waitpid()s for them
and verifies the exit status.

Replace the loops that call kill() for each process with a call to that
helper.

Link: https://lore.kernel.org/20260511162840.375890-5-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reported-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Reviewed-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: migration: make nthreads represent number of working threads

Fixture setup sets self->nthreads to number of available CPUs minus 1 and
then each test creates 'self->nthreads - 1' threads or processes, so
essentially nthreads counts the worker tasks and the main task.

Make nthreads represent the number of spawned tasks to simplify
thread/process creation and teardown.

While on it, make the fixture setup skip the tests if there are not enough
CPUs or NUMA nodes instead of checking this in each test.

Link: https://lore.kernel.org/20260511162840.375890-4-rppt@kernel.org
Reviewed-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: migration: don't assume huge page is TWOMEG

migration tests presume that both THP and HugeTLB huge pages are 2MB.

Add dynamic detection of huge page size with read_pmd_pagesize() for THP
and with default_huge_page_size() for HugeTLB.

Link: https://lore.kernel.org/20260511162840.375890-3-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Reviewed-by: Luiz Capitulino <luizcap@redhat.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Li Wang <li.wang@linux.dev>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sarthak Sharma <sarthak.sharma@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: hugetlb-read-hwpoison: add SIGBUS handler

Patch series "make MM selftests more CI friendly", v4.

There's a lot of dancing around HugeTLB settings in run_vmtests.sh.  Some
test need just a few default huge pages, some require at least 256 MB, and
some just skip lots of tests if huge pages of all supported sizes are not
available.

The goal of this set is to make tests deal with HugeTLB setup and
teardown.

There are already convenient helpers that allow easy reading and writing
of /proc and /sysfs, so adding a few APIs that will detect and update
HugeTLB settings shouldn't be a big deal.  But these nice helpers use
kselftest framework, and many of HugeTLB (and even THP) test don't, so as
a result this patchset also includes a lot of churn for conversion of
those tests to kselftest framework (patches 7-19).

The series break out:
patches 1-5:   small fixes
patch 6:       merge of hugetlb mmap tests
patch 7:       renaming of hugepage-* to hugetlb-*
patches 8-21:  mechanical conversion to kselftest framework
patches 22-28: extension of thp_settings to hugepage_settings to also include
               HugeTLB helpers
patches 29-30: add helpers for setting up SHM limits in hugetlb-shm and
               thuge-gen tests
patches 31-53: integrate the new APIs in all the tests that use HugeTLB
patches 54-55: drop HugeTLB setup from run_vmtests.sh

This patch (of 55):

Injection of a memory error with madvise() causes SIGBUS, which terminates
the hugetlb-read-hwpoison test prematurely.

Add a dummy SIGBUS handler to allow the test to continue regardless of
SIGBUS.

Link: https://lore.kernel.org/20260511162840.375890-1-rppt@kernel.org
Link: https://lore.kernel.org/20260511162840.375890-2-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Sarthak Sharma <sarthak.sharma@arm.com>
Tested-by: Li Wang <li.wang@linux.dev>
Reviewed-by: Li Wang <li.wang@linux.dev>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: add writable-file collapse tests for khugepaged

collapse_file() now supports collapsing clean pagecache folios from
writable files, so add corresponding tests.

Note that madvise(MADV_COLLAPSE) works for dirty pagecache folios from
writable files, because collapse_single_pmd() triggers a synchronous
writeback when first attempt of collapse_file() fails. That writeback
makes dirty folios clean and the retry of collapse_file() succeeds.

Link: https://lore.kernel.org/20260517135416.1434539-15-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: enable clean pagecache folio collapse for writable files

collapse_file() is capable of collapsing pagecache folios from writable
files to PMD folios.  Now enable clean pagecache folio collapse in
addition to read-only pagecache folio collapse by removing the
inode_is_open_for_write() from file_thp_enabled() and only performing
filemap_flush() if the file is read-only.

This means userspace needs to explicitly flush the content of pagecache
folios before khugepaged can collapse the folios, or use
madvise(MADV_COLLAPSE), which does the flush in the retry.  The reason is
that blindly enabling dirty pagecache folio from writable files collapse
makes khugepaged flush these folios all the time.  It is undesirable to
cause system level pagecache flushes.

To properly support dirty pagecache folio collapse, filemap_flush() needs
to be avoided.  Potentially, merging associated buffer instead of dropping
it with filemap_release_folio() might be needed.

NOTE: this breaks khugepaged selftests for writable file pagecache
collapse, which is set to fail all the time.  The next commit fixes it.

Link: https://lore.kernel.org/20260517135416.1434539-14-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: remove READ_ONLY_THP_FOR_FS code from guard-regions

Any file system with large folio support and the supported orders include
PMD_ORDER can be used. There is no need to open a file with read-only.

Link: https://lore.kernel.org/20260517135416.1434539-13-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

selftests/mm: remove READ_ONLY_THP_FOR_FS in khugepaged

Change the requirement to a file system with large folio support and the
supported order needs to include PMD_ORDER.

Also add tests of opening a file with read write permission and populating
folios with writes. Reuse the XFS image from split_huge_page_test.

Link: https://lore.kernel.org/20260517135416.1434539-12-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/btrfs: remove a comment referring to READ_ONLY_THP_FOR_FS

READ_ONLY_THP_FOR_FS is no longer present, remove related comment.

Link: https://lore.kernel.org/20260517135416.1434539-11-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: David Sterba <dsterba@suse.com>
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam@infradead.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/truncate: use folio_split() in truncate_inode_partial_folio()

After READ_ONLY_THP_FOR_FS is removed, FS either supports large folio or
not.  folio_split() can be used on a FS with large folio support without
worrying about getting a THP on a FS without large folio support.

When READ_ONLY_THP_FOR_FS was present, a PMD large pagecache folio can
appear in a FS without large folio support after khugepaged or
madvise(MADV_COLLAPSE) creates it.  During truncate_inode_partial_folio(),
such a PMD large pagecache folio is split and if the FS does not support
large folio, it needs to be split to order-0 ones and could not be split
non uniformly to ones with various orders.  try_folio_split_to_order() was
added to handle this situation by checking folio_check_splittable(...,
SPLIT_TYPE_NON_UNIFORM) to detect if the large folio is created due to
READ_ONLY_THP_FOR_FS and the FS does not support large folio.  Now
READ_ONLY_THP_FOR_FS is removed, all large pagecache folios are created
with FSes supporting large folio, this function is no longer needed and
all large pagecache folios can be split non uniformly.

Link: https://lore.kernel.org/20260517135416.1434539-10-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/huge_memory: remove folio split check for READ_ONLY_THP_FOR_FS

Without READ_ONLY_THP_FOR_FS, large file-backed folios cannot be created
by a FS without large folio support. The check is no longer needed.

Link: https://lore.kernel.org/20260517135416.1434539-9-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam Howlett <liam@infradead.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs: remove nr_thps from struct address_space

filemap_nr_thps*() are removed, the related field, address_space->nr_thps,
is no longer needed. Remove it. This shrinks struct address_space by 8
bytes on 64-bit systems which may increase the number of inodes we can
cache.

Link: https://lore.kernel.org/20260517135416.1434539-8-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Nico Pache <npache@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: fs: remove filemap_nr_thps*() functions and their users

They are used by READ_ONLY_THP_FOR_FS to handle writes to FSes without
large folio support, so that read-only THPs created in these FSes are not
seen by the FSes when the underlying fd becomes writable. Now read-only
PMD THPs only appear in a FS with large folio support and the supported
orders include PMD_ORDER.

READ_ONLY_THP_FOR_FS was using mapping->nr_thps, inode->i_writecount, and
smp_mb() to prevent writes to a read-only THP and collapsing writable
folios into a THP. In collapse_file(), mapping->nr_thps is increased,
then smp_mb(), and if inode->i_writecount > 0, collapse is stopped, while
do_dentry_open() first increases inode->i_writecount, then a full memory
fence, and if mapping->nr_thps > 0, all read-only THPs are truncated.

Now this mechanism can be removed along with READ_ONLY_THP_FOR_FS code,
since a dirty folio check has been added after try_to_unmap() in
collapse_file() to prevent dirty folios from being collapsed as clean.

Link: https://lore.kernel.org/20260517135416.1434539-7-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: remove READ_ONLY_THP_FOR_FS Kconfig option

After removing READ_ONLY_THP_FOR_FS check in file_thp_enabled(),
khugepaged and MADV_COLLAPSE can run on FSes with PMD THP pagecache
support even without READ_ONLY_THP_FOR_FS enabled. Remove the Kconfig
first so that no one can use READ_ONLY_THP_FOR_FS as upcoming commits
remove mapping->nr_thps, which its safe guard mechanism relies on.

Link: https://lore.kernel.org/20260517135416.1434539-6-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Nico Pache <npache@redhat.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam Howlett <liam@infradead.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: remove READ_ONLY_THP_FOR_FS check in hugepage_enabled()

Remove the READ_ONLY_THP_FOR_FS gate and khugepaged for file-backed
pmd-sized hugepages are enabled by the global transparent hugepage
control. khugepaged can still be enabled by per-size control for anon and
shmem when the global control is off.

Add shmem_hpage_pmd_enabled() stub for !CONFIG_SHMEM to remove
IS_ENABLED(SHMEM) in hugepage_enabled().

Clean up hugepage_enabled() by moving anon code to anon_hpage_enabled().

Link: https://lore.kernel.org/20260517135416.1434539-5-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Nico Pache <npache@redhat.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/huge_memory: remove READ_ONLY_THP_FOR_FS from file_thp_enabled()

Replace it with a check on the max folio order of the file's address space
mapping, making sure PMD folio is supported. Keep the inode
open-for-write check, since even if collapse_file() now makes sure all
to-be-collapsed folios are clean and the created PMD file THP can be
handled by FSes properly, the filemap_flush() could perform undesirable
write back.

Link: https://lore.kernel.org/20260517135416.1434539-4-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Nico Pache <npache@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: add folio dirty check after try_to_unmap()

This check ensures the correctness of read-only PMD folio collapse after
it is enabled for all FSes supporting PMD pagecache folios and replaces
READ_ONLY_THP_FOR_FS.

READ_ONLY_THP_FOR_FS only supports read-only fd and uses mapping->nr_thps
and inode->i_writecount to prevent any write to read-only to-be-collapsed
folios. In upcoming commits, READ_ONLY_THP_FOR_FS will be removed and the
aforementioned mechanism will go away too. To ensure khugepaged functions
as expected after the changes, skip if any folio is dirty after
try_to_unmap(), since a dirty folio at that point means this read-only
folio can get writes between try_to_unmap() and try_to_unmap_flush() via
cached TLB entries and khugepaged does not support writable pagecache
folio collapse yet.

Link: https://lore.kernel.org/20260517135416.1434539-3-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Nico Pache <npache@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: remove READ_ONLY_THP_FOR_FS check

Patch series "Remove CONFIG_READ_ONLY_THP_FOR_FS and enable file THP for
writable files", v6.

This patch (of 14):

collapse_file() requires FSes supporting large folio with at least
PMD_ORDER, so replace the READ_ONLY_THP_FOR_FS check with that.
MADV_COLLAPSE ignores shmem huge config, so exclude the check for shmem.

While at it, replace VM_BUG_ON with VM_WARN_ON_ONCE.

Add a helper function mapping_pmd_folio_support() for FSes supporting
large folio with at least PMD_ORDER.

Link: https://lore.kernel.org/20260517135416.1434539-1-ziy@nvidia.com
Link: https://lore.kernel.org/20260517135416.1434539-2-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Nico Pache <npache@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: fix PMD collapse swap PTE accounting

mthp_collapse() uses mthp_present_ptes to decide whether a range has
enough occupied PTEs to try collapse.  Swap PTEs accepted by
collapse_scan_pmd() are counted in unmapped, but are not represented in
mthp_present_ptes.

When lower orders are enabled, collapse_scan_pmd() relaxes max_ptes_none
so the scan can cover the whole PMD and build the bitmap.  mthp_collapse()
then checks the PMD-order candidate using the bitmap.

With max_ptes_none set to 0, a range with 511 present PTEs and one swap
PTE no longer reaches collapse_huge_page(), even though PMD collapse can
handle swap PTEs up to max_ptes_swap.

Account unmapped PTEs only for PMD order.  PMD collapse supports swap PTEs
through max_ptes_swap, while lower-order mTHP collapse does not currently
support non-present PTEs.  Keep non-present PTEs out of the lower-order
eligibility check.

Link: https://lore.kernel.org/20260609120443.71864-1-lance.yang@linux.dev
Fixes: 90ed32d00054 ("mm/khugepaged: introduce mTHP collapse support")
Signed-off-by: Lance Yang <lance.yang@linux.dev>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: Nico Pache <npache@redhat.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation: mm: update the admin guide for mTHP collapse

Now that we can collapse to mTHPs lets update the admin guide to reflect
these changes and provide proper guidance on how to utilize it.

Link: https://lore.kernel.org/20260605161422.213817-15-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Takashi Iwai (SUSE) <tiwai@suse.de>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: run khugepaged for all orders

If any order (m)THP is enabled we should allow running khugepaged to
attempt scanning and collapsing mTHPs. In order for khugepaged to operate
when only mTHP sizes are specified in sysfs, we must modify the predicate
function that determines whether it ought to run to do so.

This function is currently called hugepage_pmd_enabled(), this patch
renames it to hugepage_enabled() and updates the logic to check to
determine whether any valid orders may exist which would justify
khugepaged running.

We must also update collapse_possible_orders() to check all orders if the
vma is anonymous and the collapse is khugepaged.

After this patch khugepaged mTHP collapse is fully enabled.

Link: https://lore.kernel.org/20260605161422.213817-14-npache@redhat.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Nico Pache <npache@redhat.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Acked-by: Usama Arif <usama.arif@linux.dev>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Takashi Iwai (SUSE) <tiwai@suse.de>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: avoid unnecessary mTHP collapse attempts

There are cases where, if an attempted collapse fails, all subsequent
orders are guaranteed to also fail. Avoid these collapse attempts by
bailing out early.

Link: https://lore.kernel.org/20260605161422.213817-13-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: Usama Arif <usama.arif@linux.dev>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Takashi Iwai (SUSE) <tiwai@suse.de>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: introduce mTHP collapse support

Enable khugepaged to collapse to mTHP orders.  This patch implements the
main scanning logic using a bitmap to track occupied pages and the
algorithm to find optimal collapse sizes.

Previous to this patch, PMD collapse had 3 main phases, a light weight
scanning phase (mmap_read_lock) that determines a potential PMD collapse,
an alloc phase (mmap unlocked), then finally heavier collapse phase
(mmap_write_lock).

To enabled mTHP collapse we make the following changes:

During PMD scan phase, track occupied pages in a bitmap.  When mTHP orders
are enabled, we remove the restriction of max_ptes_none during the scan
phase to avoid missing potential mTHP collapse candidates.  Once we have
scanned the full PMD range and updated the bitmap to track occupied pages,
we use the bitmap to find the optimal mTHP size.

Implement mthp_collapse() to walk forward through the bitmap and determine
the best eligible order for each naturally-aligned region.  The algorithm
starts at the beginning of the PMD range and, for each offset, tries the
highest order that fits the alignment.  If the number of occupied PTEs in
that region satisfies the max_ptes_none threshold for that order, a
collapse is attempted.  On failure, the order is decremented and the same
offset is retried at the next smaller size.  Once the smallest enabled
order is exhausted (or a collapse succeeds), the offset advances past the
region just processed, and the next attempt starts at the highest order
permitted by the new offset's natural alignment.

The algorithm works as follows:
    1) set offset=0 and order=HPAGE_PMD_ORDER
    2) if the order is not enabled, go to step (5)
    3) count occupied PTEs in the (offset, order) range using
       bitmap_weight_from()
    4) if the count satisfies the max_ptes_none threshold, attempt
       collapse; on success, advance to step (6)
    5) if a smaller enabled order exists, decrement order and retry
       from step (2) at the same offset
    6) advance offset past the current region and compute the next
       order from the new offset's natural alignment via __ffs(offset),
       capped at HPAGE_PMD_ORDER
    7) repeat from step (2) until the full PMD range is covered

mTHP collapses reject regions containing swapped out or shared pages.
This is because adding new entries can lead to new none pages, and these
may lead to constant promotion into a higher order mTHP.  A similar issue
can occur with "max_ptes_none > HPAGE_PMD_NR/2" due to a collapse
introducing at least 2x the number of pages, and on a future scan will
satisfy the promotion condition once again.  This issue is prevented via
the collapse_max_ptes_none() function which imposes the max_ptes_none
restrictions above.

We currently only support mTHP collapse for max_ptes_none values of 0 and
HPAGE_PMD_NR - 1.  resulting in the following behavior:

    - max_ptes_none=0: Never introduce new empty pages during collapse
    - max_ptes_none=HPAGE_PMD_NR-1: Always try collapse to the highest
      available mTHP order

Any other max_ptes_none value will emit a warning and default mTHP
collapse to max_ptes_none=0.  There should be no behavior change for PMD
collapse.

Once we determine what mTHP sizes fits best in that PMD range a collapse
is attempted.  A minimum collapse order of 2 is used as this is the lowest
order supported by anon memory as defined by THP_ORDERS_ALL_ANON.

Currently madv_collapse is not supported and will only attempt PMD
collapse.

We can also remove the check for is_khugepaged inside the PMD scan as the
collapse_max_ptes_none() function handles this logic now.

Link: https://lore.kernel.org/20260605161422.213817-12-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Takashi Iwai (SUSE) <tiwai@suse.de>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: introduce collapse_possible_orders helper functions

Add collapse_possible_orders() to generalize THP order eligibility. The
function determines which THP orders are permitted based on collapse
context (khugepaged vs madv_collapse). We also add collapse_possible() as
a thin wrapper around collapse_possible_orders() that returns a bool
rather than the whole bitmap.

This consolidates collapse configuration logic and provides a clean
interface for future mTHP collapse support where the orders may be
different.

Link: https://lore.kernel.org/20260605161422.213817-11-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Takashi Iwai (SUSE) <tiwai@suse.de>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Usama Arif <usama.arif@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: improve tracepoints for mTHP orders

Add the order to the mm_collapse_huge_page<_swapin,_isolate> tracepoints
to give better insight into what order is being operated at for.

Link: https://lore.kernel.org/20260605161422.213817-10-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Takashi Iwai (SUSE) <tiwai@suse.de>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: add per-order mTHP collapse failure statistics

Add three new mTHP statistics to track collapse failures for different
orders when encountering swap PTEs, excessive none PTEs, and shared PTEs:

- collapse_exceed_swap_pte: Increment when mTHP collapse fails due to
encountering a swap PTE.

- collapse_exceed_none_pte: Counts when mTHP collapse fails due to
exceeding the none PTE threshold for the given order

- collapse_exceed_shared_pte: Counts when mTHP collapse fails due to
encountering a shared PTE.

These statistics complement the existing THP_SCAN_EXCEED_* events by
providing per-order granularity for mTHP collapse attempts. The stats are
exposed via sysfs under
`/sys/kernel/mm/transparent_hugepage/hugepages-*/stats/` for each
supported hugepage size.

As we currently do not support collapsing mTHPs that contain a swap or
shared entry, those statistics keep track of how often we are encountering
failed mTHP collapses due to these restrictions.

We will add support for mTHP collapse for anonymous pages next; lets also
track when this happens at the PMD level within the per-mTHP stats.

Link: https://lore.kernel.org/20260605161422.213817-9-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Takashi Iwai (SUSE) <tiwai@suse.de>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: skip collapsing mTHP to smaller orders

khugepaged may try to collapse a mTHP to a folio of equal or smaller size,
possibly resulting in a partially mapped source folio, which is undesired.
Skip these cases until we have a way to check if its ok to collapse to a
smaller mTHP size (like in the case of a partially mapped folio). This
check is not done during the scan phase as the current collapse order is
unknown at that time.

This patch is inspired by Dev Jain's work on khugepaged mTHP support [1].

Link: https://lore.kernel.org/20260605161422.213817-8-npache@redhat.com
Link: https://lore.kernel.org/lkml/20241216165105.56185-11-dev.jain@arm.com/
Co-developed-by: Dev Jain <dev.jain@arm.com>
Signed-off-by: Dev Jain <dev.jain@arm.com>
Signed-off-by: Nico Pache <npache@redhat.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand (arm) <david@kernel.org>
Acked-by: Usama Arif <usama.arif@linux.dev>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Takashi Iwai (SUSE) <tiwai@suse.de>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: generalize collapse_huge_page for mTHP collapse

Pass an order to collapse_huge_page to support collapsing anon memory to
arbitrary orders within a PMD.  order indicates what mTHP size we are
attempting to collapse to.

For non-PMD collapse we must leave the anon VMA write locked until after
we collapse the mTHP-- in the PMD case all the pages are isolated, but in
the mTHP case this is not true, and we must keep the lock to prevent
access/changes to the page tables.  This can happen if the rmap walkers
hit a pmd_none while the PMD entry is currently unavailable due to being
temporarily removed during the collapse phase.

To properly establish the page table hierarchy without violating any
expectations from certain architectures (e.g.  MIPS), we must make sure to
have the PMD reinstalled before the PTEs, and hold both PTE/PMD locks
before calling update_mmu_cache_range() (if they are distinct locks).

Link: https://lore.kernel.org/20260605161422.213817-7-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Takashi Iwai (SUSE) <tiwai@suse.de>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: require collapse_huge_page to enter/exit with the lock dropped

Currently the collapse_huge_page function requires the mmap_read_lock to
enter with it held, and exit with it dropped. This function moves the
unlock into its parent caller, and changes this semantic to requiring it
to enter/exit with it always unlocked.

In future patches, we need this expectation, as for in mTHP collapse, we
may have already dropped the lock, and do not want to conditionally check
for this by passing through the lock_dropped variable.

No functional change is expected as one of the first things the
collapse_huge_page function does is drop this lock before allocating the
hugepage.

Link: https://lore.kernel.org/20260605161422.213817-6-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Takashi Iwai (SUSE) <tiwai@suse.de>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: generalize __collapse_huge_page_* for mTHP support

generalize the order of the __collapse_huge_page_* and collapse_max_*
functions to support future mTHP collapse.

The current mechanism for determining collapse with the
khugepaged_max_ptes_none value is not designed with mTHP in mind.  This
raises a key design issue: if we support user defined max_pte_none values
(even those scaled by order), a collapse of a lower order can introduces
an feedback loop, or "creep", when max_ptes_none is set to a value greater
than HPAGE_PMD_NR / 2.  [1]

With this configuration, a successful collapse to order N will populate
enough pages to satisfy the collapse condition on order N+1 on the next
scan.  This leads to unnecessary work and memory churn.

To fix this issue introduce a helper function that will limit mTHP
collapse support to two max_ptes_none values, 0 and HPAGE_PMD_NR - 1.
This effectively supports two modes: [2]

- max_ptes_none=0: never collapses if it encounters an empty PTE or a PTE
  that maps the shared zeropage. Consequently, no memory bloat.
- max_ptes_none=511 (on 4k pagesz): Always collapse to the highest
  available mTHP order.

This removes the possibility of "creep", and a warning will be emitted if
any non-supported max_ptes_none value is configured with mTHP enabled.
Any intermediate value will default mTHP collapse to max_ptes_none=0.

mTHP collapse will not honor the khugepaged_max_ptes_shared or
khugepaged_max_ptes_swap parameters, and will fail if it encounters a
shared or swapped entry.

No functional changes in this patch; however it defines future behavior
for mTHP collapse.

Link: https://lore.kernel.org/20260605161422.213817-5-npache@redhat.com
Link: https://lore.kernel.org/all/e46ab3ab-a3d7-4fb7-9970-d0704bd5d05a@arm.com
Link: https://lore.kernel.org/all/37375ace-5601-4d6c-9dac-d1c8268698e9@redhat.com
Co-developed-by: Dev Jain <dev.jain@arm.com>
Signed-off-by: Dev Jain <dev.jain@arm.com>
Signed-off-by: Nico Pache <npache@redhat.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Acked-by: David Hildenbrand (arm) <david@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Takashi Iwai (SUSE) <tiwai@suse.de>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: rework max_ptes_* handling with helper functions

The following cleanup reworks all the max_ptes_* handling into helper
functions. This increases the code readability and will later be used to
implement the mTHP handling of these variables.

With these changes we abstract all the madvise_collapse() special casing
(do not respect the sysctls) away from the functions that utilize them.
And will be used later in this series to cleanly restrict the mTHP
collapse behavior.

No functional change is intended; however, we are now only reading the
sysfs variables once per scan, whereas before these variables were being
read on each loop iteration.

Link: https://lore.kernel.org/20260605161422.213817-4-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Suggested-by: David Hildenbrand <david@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Usama Arif <usama.arif@linux.dev>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Takashi Iwai (SUSE) <tiwai@suse.de>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/khugepaged: generalize alloc_charge_folio()

Pass order to alloc_charge_folio() and update mTHP statistics.

Link: https://lore.kernel.org/20260605161422.213817-3-npache@redhat.com
Signed-off-by: Dev Jain <dev.jain@arm.com>
Co-developed-by: Nico Pache <npache@redhat.com>
Signed-off-by: Nico Pache <npache@redhat.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Usama Arif <usama.arif@linux.dev>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rafael Aquini <raquini@redhat.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shivank Garg <shivankg@amd.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Takashi Iwai (SUSE) <tiwai@suse.de>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>