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>

diff --git a/tools/testing/selftests/mm/compaction_test.c b/tools/testing/selftests/mm/compaction_test.c
index 30209c40b69778d16e31c35b63dab02b02c0b725..de0633f9a7e50e4763d1d1364e418af9cba0908a 100644 (file)
--- a/tools/testing/selftests/mm/compaction_test.c
+++ b/tools/testing/selftests/mm/compaction_test.c
@@ -17,6 +17,7 @@
 #include <string.h>
 
 #include "kselftest.h"
+#include "hugepage_settings.h"
 
 #define MAP_SIZE_MB    100
 #define MAP_SIZE       (MAP_SIZE_MB * 1024 * 1024)
@@ -82,124 +83,44 @@ int prereq(void)
        return -1;
 }
 
-int check_compaction(unsigned long mem_free, unsigned long hugepage_size,
-                    unsigned long initial_nr_hugepages)
+int check_compaction(unsigned long mem_free, unsigned long hugepage_size)
 {
-       unsigned long nr_hugepages_ul;
-       int fd, ret = -1;
+       unsigned long nr_hugepages;
        int compaction_index = 0;
-       char nr_hugepages[20] = {0};
-       char init_nr_hugepages[24] = {0};
-       char target_nr_hugepages[24] = {0};
-       int slen;
-
-       snprintf(init_nr_hugepages, sizeof(init_nr_hugepages),
-                "%lu", initial_nr_hugepages);
+       int ret = -1;
 
        /* We want to test with 80% of available memory. Else, OOM killer comes
           in to play */
        mem_free = mem_free * 0.8;
 
-       fd = open("/proc/sys/vm/nr_hugepages", O_RDWR | O_NONBLOCK);
-       if (fd < 0) {
-               ksft_print_msg("Failed to open /proc/sys/vm/nr_hugepages: %s\n",
-                              strerror(errno));
-               ret = -1;
-               goto out;
-       }
-
        /*
         * Request huge pages for about half of the free memory. The Kernel
         * will allocate as much as it can, and we expect it will get at least 1/3
         */
-       nr_hugepages_ul = mem_free / hugepage_size / 2;
-       snprintf(target_nr_hugepages, sizeof(target_nr_hugepages),
-                "%lu", nr_hugepages_ul);
-
-       slen = strlen(target_nr_hugepages);
-       if (write(fd, target_nr_hugepages, slen) != slen) {
-               ksft_print_msg("Failed to write %lu to /proc/sys/vm/nr_hugepages: %s\n",
-                              nr_hugepages_ul, strerror(errno));
-               goto close_fd;
-       }
-
-       lseek(fd, 0, SEEK_SET);
-
-       if (read(fd, nr_hugepages, sizeof(nr_hugepages)) <= 0) {
-               ksft_print_msg("Failed to re-read from /proc/sys/vm/nr_hugepages: %s\n",
-                              strerror(errno));
-               goto close_fd;
-       }
+       nr_hugepages = mem_free / hugepage_size / 2;
+       hugetlb_set_nr_default_pages(nr_hugepages);
 
        /* We should have been able to request at least 1/3 rd of the memory in
           huge pages */
-       nr_hugepages_ul = strtoul(nr_hugepages, NULL, 10);
-       if (!nr_hugepages_ul) {
+       nr_hugepages = hugetlb_nr_default_pages();
+       if (!nr_hugepages) {
                ksft_print_msg("ERROR: No memory is available as huge pages\n");
-               goto close_fd;
-       }
-       compaction_index = mem_free/(nr_hugepages_ul * hugepage_size);
-
-       lseek(fd, 0, SEEK_SET);
-
-       if (write(fd, init_nr_hugepages, strlen(init_nr_hugepages))
-           != strlen(init_nr_hugepages)) {
-               ksft_print_msg("Failed to write value to /proc/sys/vm/nr_hugepages: %s\n",
-                              strerror(errno));
-               goto close_fd;
+               goto out;
        }
+       compaction_index = mem_free/(nr_hugepages * hugepage_size);
 
-       ksft_print_msg("Number of huge pages allocated = %lu\n",
-                      nr_hugepages_ul);
+       ksft_print_msg("Number of huge pages allocated = %lu\n", nr_hugepages);
 
        if (compaction_index > 3) {
                ksft_print_msg("ERROR: Less than 1/%d of memory is available\n"
                               "as huge pages\n", compaction_index);
-               goto close_fd;
-       }
-
-       ret = 0;
-
- close_fd:
-       close(fd);
- out:
-       ksft_test_result(ret == 0, "check_compaction\n");
-       return ret;
-}
-
-int set_zero_hugepages(unsigned long *initial_nr_hugepages)
-{
-       int fd, ret = -1;
-       char nr_hugepages[20] = {0};
-
-       fd = open("/proc/sys/vm/nr_hugepages", O_RDWR | O_NONBLOCK);
-       if (fd < 0) {
-               ksft_print_msg("Failed to open /proc/sys/vm/nr_hugepages: %s\n",
-                              strerror(errno));
                goto out;
        }
-       if (read(fd, nr_hugepages, sizeof(nr_hugepages)) <= 0) {
-               ksft_print_msg("Failed to read from /proc/sys/vm/nr_hugepages: %s\n",
-                              strerror(errno));
-               goto close_fd;
-       }
-
-       lseek(fd, 0, SEEK_SET);
 
-       /* Start with the initial condition of 0 huge pages */
-       if (write(fd, "0", sizeof(char)) != sizeof(char)) {
-               ksft_print_msg("Failed to write 0 to /proc/sys/vm/nr_hugepages: %s\n",
-                              strerror(errno));
-               goto close_fd;
-       }
-
-       *initial_nr_hugepages = strtoul(nr_hugepages, NULL, 10);
        ret = 0;
 
- close_fd:
-       close(fd);
-
  out:
+       ksft_test_result(ret == 0, "check_compaction\n");
        return ret;
 }
 
@@ -212,18 +133,17 @@ int main(int argc, char **argv)
        unsigned long mem_free = 0;
        unsigned long hugepage_size = 0;
        long mem_fragmentable_MB = 0;
-       unsigned long initial_nr_hugepages;
 
        ksft_print_header();
 
        if (prereq() || geteuid())
                ksft_exit_skip("Prerequisites unsatisfied\n");
 
-       ksft_set_plan(1);
-
        /* Start the test without hugepages reducing mem_free */
-       if (set_zero_hugepages(&initial_nr_hugepages))
-               ksft_exit_fail();
+       if (!hugetlb_setup_default_exact(0))
+               ksft_exit_skip("Could not reset nr_hugepages\n");
+
+       ksft_set_plan(1);
 
        lim.rlim_cur = RLIM_INFINITY;
        lim.rlim_max = RLIM_INFINITY;
@@ -268,8 +188,7 @@ int main(int argc, char **argv)
                entry = entry->next;
        }
 
-       if (check_compaction(mem_free, hugepage_size,
-                            initial_nr_hugepages) == 0)
+       if (check_compaction(mem_free, hugepage_size) == 0)
                ksft_exit_pass();
 
        ksft_exit_fail();