+++ /dev/null
-From d3921cb8be29ce5668c64e23ffdaeec5f8c69399 Mon Sep 17 00:00:00 2001
-From: Mike Rapoport <rppt@kernel.org>
-Date: Sat, 23 Jan 2021 21:01:02 -0800
-Subject: mm: fix initialization of struct page for holes in memory layout
-
-From: Mike Rapoport <rppt@linux.ibm.com>
-
-commit d3921cb8be29ce5668c64e23ffdaeec5f8c69399 upstream.
-
-There could be struct pages that are not backed by actual physical
-memory. This can happen when the actual memory bank is not a multiple
-of SECTION_SIZE or when an architecture does not register memory holes
-reserved by the firmware as memblock.memory.
-
-Such pages are currently initialized using init_unavailable_mem()
-function that iterates through PFNs in holes in memblock.memory and if
-there is a struct page corresponding to a PFN, the fields if this page
-are set to default values and the page is marked as Reserved.
-
-init_unavailable_mem() does not take into account zone and node the page
-belongs to and sets both zone and node links in struct page to zero.
-
-On a system that has firmware reserved holes in a zone above ZONE_DMA,
-for instance in a configuration below:
-
- # grep -A1 E820 /proc/iomem
- 7a17b000-7a216fff : Unknown E820 type
- 7a217000-7bffffff : System RAM
-
-unset zone link in struct page will trigger
-
- VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
-
-because there are pages in both ZONE_DMA32 and ZONE_DMA (unset zone link
-in struct page) in the same pageblock.
-
-Update init_unavailable_mem() to use zone constraints defined by an
-architecture to properly setup the zone link and use node ID of the
-adjacent range in memblock.memory to set the node link.
-
-Link: https://lkml.kernel.org/r/20210111194017.22696-3-rppt@kernel.org
-Fixes: 73a6e474cb37 ("mm: memmap_init: iterate over memblock regions rather that check each PFN")
-Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
-Reported-by: Andrea Arcangeli <aarcange@redhat.com>
-Cc: Andrea Arcangeli <aarcange@redhat.com>
-Cc: Baoquan He <bhe@redhat.com>
-Cc: Borislav Petkov <bp@alien8.de>
-Cc: David Hildenbrand <david@redhat.com>
-Cc: "H. Peter Anvin" <hpa@zytor.com>
-Cc: Ingo Molnar <mingo@redhat.com>
-Cc: Mel Gorman <mgorman@suse.de>
-Cc: Michal Hocko <mhocko@kernel.org>
-Cc: Qian Cai <cai@lca.pw>
-Cc: Thomas Gleixner <tglx@linutronix.de>
-Cc: Vlastimil Babka <vbabka@suse.cz>
-Cc: <stable@vger.kernel.org>
-Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
----
- mm/page_alloc.c | 84 +++++++++++++++++++++++++++++++++-----------------------
- 1 file changed, 50 insertions(+), 34 deletions(-)
-
---- a/mm/page_alloc.c
-+++ b/mm/page_alloc.c
-@@ -7003,23 +7003,26 @@ void __init free_area_init_memoryless_no
- * Initialize all valid struct pages in the range [spfn, epfn) and mark them
- * PageReserved(). Return the number of struct pages that were initialized.
- */
--static u64 __init init_unavailable_range(unsigned long spfn, unsigned long epfn)
-+static u64 __init init_unavailable_range(unsigned long spfn, unsigned long epfn,
-+ int zone, int nid)
- {
-- unsigned long pfn;
-+ unsigned long pfn, zone_spfn, zone_epfn;
- u64 pgcnt = 0;
-
-+ zone_spfn = arch_zone_lowest_possible_pfn[zone];
-+ zone_epfn = arch_zone_highest_possible_pfn[zone];
-+
-+ spfn = clamp(spfn, zone_spfn, zone_epfn);
-+ epfn = clamp(epfn, zone_spfn, zone_epfn);
-+
- for (pfn = spfn; pfn < epfn; pfn++) {
- if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
- pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
- + pageblock_nr_pages - 1;
- continue;
- }
-- /*
-- * Use a fake node/zone (0) for now. Some of these pages
-- * (in memblock.reserved but not in memblock.memory) will
-- * get re-initialized via reserve_bootmem_region() later.
-- */
-- __init_single_page(pfn_to_page(pfn), pfn, 0, 0);
-+
-+ __init_single_page(pfn_to_page(pfn), pfn, zone, nid);
- __SetPageReserved(pfn_to_page(pfn));
- pgcnt++;
- }
-@@ -7028,51 +7031,64 @@ static u64 __init init_unavailable_range
- }
-
- /*
-- * Only struct pages that are backed by physical memory are zeroed and
-- * initialized by going through __init_single_page(). But, there are some
-- * struct pages which are reserved in memblock allocator and their fields
-- * may be accessed (for example page_to_pfn() on some configuration accesses
-- * flags). We must explicitly initialize those struct pages.
-+ * Only struct pages that correspond to ranges defined by memblock.memory
-+ * are zeroed and initialized by going through __init_single_page() during
-+ * memmap_init().
- *
-- * This function also addresses a similar issue where struct pages are left
-- * uninitialized because the physical address range is not covered by
-- * memblock.memory or memblock.reserved. That could happen when memblock
-- * layout is manually configured via memmap=, or when the highest physical
-- * address (max_pfn) does not end on a section boundary.
-+ * But, there could be struct pages that correspond to holes in
-+ * memblock.memory. This can happen because of the following reasons:
-+ * - phyiscal memory bank size is not necessarily the exact multiple of the
-+ * arbitrary section size
-+ * - early reserved memory may not be listed in memblock.memory
-+ * - memory layouts defined with memmap= kernel parameter may not align
-+ * nicely with memmap sections
-+ *
-+ * Explicitly initialize those struct pages so that:
-+ * - PG_Reserved is set
-+ * - zone link is set accorging to the architecture constrains
-+ * - node is set to node id of the next populated region except for the
-+ * trailing hole where last node id is used
- */
--static void __init init_unavailable_mem(void)
-+static void __init init_zone_unavailable_mem(int zone)
- {
-- phys_addr_t start, end;
-- u64 i, pgcnt;
-- phys_addr_t next = 0;
-+ unsigned long start, end;
-+ int i, nid;
-+ u64 pgcnt;
-+ unsigned long next = 0;
-
- /*
-- * Loop through unavailable ranges not covered by memblock.memory.
-+ * Loop through holes in memblock.memory and initialize struct
-+ * pages corresponding to these holes
- */
- pgcnt = 0;
-- for_each_mem_range(i, &start, &end) {
-+ for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
- if (next < start)
-- pgcnt += init_unavailable_range(PFN_DOWN(next),
-- PFN_UP(start));
-+ pgcnt += init_unavailable_range(next, start, zone, nid);
- next = end;
- }
-
- /*
-- * Early sections always have a fully populated memmap for the whole
-- * section - see pfn_valid(). If the last section has holes at the
-- * end and that section is marked "online", the memmap will be
-- * considered initialized. Make sure that memmap has a well defined
-- * state.
-+ * Last section may surpass the actual end of memory (e.g. we can
-+ * have 1Gb section and 512Mb of RAM pouplated).
-+ * Make sure that memmap has a well defined state in this case.
- */
-- pgcnt += init_unavailable_range(PFN_DOWN(next),
-- round_up(max_pfn, PAGES_PER_SECTION));
-+ end = round_up(max_pfn, PAGES_PER_SECTION);
-+ pgcnt += init_unavailable_range(next, end, zone, nid);
-
- /*
- * Struct pages that do not have backing memory. This could be because
- * firmware is using some of this memory, or for some other reasons.
- */
- if (pgcnt)
-- pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt);
-+ pr_info("Zone %s: zeroed struct page in unavailable ranges: %lld pages", zone_names[zone], pgcnt);
-+}
-+
-+static void __init init_unavailable_mem(void)
-+{
-+ int zone;
-+
-+ for (zone = 0; zone < ZONE_MOVABLE; zone++)
-+ init_zone_unavailable_mem(zone);
- }
- #else
- static inline void __init init_unavailable_mem(void)
projects / thirdparty / kernel / stable-queue.git / commitdiff
