From: Ryan Roberts ryan.roberts@arm.com
mainline inclusion from mainline-v6.8-rc1 commit 9f0704eae8a4edc8dca9c8a297f798d505a4103a category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I98AW9 CVE: NA
-------------------------------------------------
The `collapse_max_ptes_none` test was previously failing when a THP size less than PMD-size had enabled="always". The root cause is because the test faults in 1 page less than the threshold it set for collapsing. But when THP is enabled always, we "over allocate" and therefore the threshold is passed, and collapse unexpectedly succeeds.
Solve this by enlightening khugepaged selftest. Add a command line option to pass in the desired THP size that should be used for all anonymous allocations. The harness will then explicitly configure a THP size as requested and modify the `collapse_max_ptes_none` test so that it faults in the threshold minus the number of pages in the configured THP size. If no command line option is provided, default to order 0, as per previous behaviour.
I chose to use an order in the command line interface, since this makes the interface agnostic of base page size, making it easier to invoke from run_vmtests.sh.
Link: https://lkml.kernel.org/r/20231207161211.2374093-9-ryan.roberts@arm.com Signed-off-by: Ryan Roberts ryan.roberts@arm.com Tested-by: Kefeng Wang wangkefeng.wang@huawei.com Tested-by: John Hubbard jhubbard@nvidia.com Cc: Alistair Popple apopple@nvidia.com Cc: Anshuman Khandual anshuman.khandual@arm.com Cc: Barry Song v-songbaohua@oppo.com Cc: Catalin Marinas catalin.marinas@arm.com Cc: David Hildenbrand david@redhat.com Cc: David Rientjes rientjes@google.com Cc: "Huang, Ying" ying.huang@intel.com Cc: Hugh Dickins hughd@google.com Cc: Itaru Kitayama itaru.kitayama@gmail.com Cc: Kirill A. Shutemov kirill.shutemov@linux.intel.com Cc: Luis Chamberlain mcgrof@kernel.org Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: Vlastimil Babka vbabka@suse.cz Cc: Yang Shi shy828301@gmail.com Cc: Yin Fengwei fengwei.yin@intel.com Cc: Yu Zhao yuzhao@google.com Cc: Zi Yan ziy@nvidia.com Signed-off-by: Andrew Morton akpm@linux-foundation.org (cherry picked from commit 9f0704eae8a4edc8dca9c8a297f798d505a4103a) Signed-off-by: Kefeng Wang wangkefeng.wang@huawei.com --- tools/testing/selftests/mm/khugepaged.c | 48 +++++++++++++++++------ tools/testing/selftests/mm/run_vmtests.sh | 2 + 2 files changed, 39 insertions(+), 11 deletions(-)
diff --git a/tools/testing/selftests/mm/khugepaged.c b/tools/testing/selftests/mm/khugepaged.c index 7bd3baa9d34b..829320a519e7 100644 --- a/tools/testing/selftests/mm/khugepaged.c +++ b/tools/testing/selftests/mm/khugepaged.c @@ -28,6 +28,7 @@ static unsigned long hpage_pmd_size; static unsigned long page_size; static int hpage_pmd_nr; +static int anon_order;
#define PID_SMAPS "/proc/self/smaps" #define TEST_FILE "collapse_test_file" @@ -607,6 +608,11 @@ static bool is_tmpfs(struct mem_ops *ops) return ops == &__file_ops && finfo.type == VMA_SHMEM; }
+static bool is_anon(struct mem_ops *ops) +{ + return ops == &__anon_ops; +} + static void alloc_at_fault(void) { struct thp_settings settings = *thp_current_settings(); @@ -673,6 +679,7 @@ static void collapse_max_ptes_none(struct collapse_context *c, struct mem_ops *o int max_ptes_none = hpage_pmd_nr / 2; struct thp_settings settings = *thp_current_settings(); void *p; + int fault_nr_pages = is_anon(ops) ? 1 << anon_order : 1;
settings.khugepaged.max_ptes_none = max_ptes_none; thp_push_settings(&settings); @@ -686,10 +693,10 @@ static void collapse_max_ptes_none(struct collapse_context *c, struct mem_ops *o goto skip; }
- ops->fault(p, 0, (hpage_pmd_nr - max_ptes_none - 1) * page_size); + ops->fault(p, 0, (hpage_pmd_nr - max_ptes_none - fault_nr_pages) * page_size); c->collapse("Maybe collapse with max_ptes_none exceeded", p, 1, ops, !c->enforce_pte_scan_limits); - validate_memory(p, 0, (hpage_pmd_nr - max_ptes_none - 1) * page_size); + validate_memory(p, 0, (hpage_pmd_nr - max_ptes_none - fault_nr_pages) * page_size);
if (c->enforce_pte_scan_limits) { ops->fault(p, 0, (hpage_pmd_nr - max_ptes_none) * page_size); @@ -1076,7 +1083,7 @@ static void madvise_retracted_page_tables(struct collapse_context *c,
static void usage(void) { - fprintf(stderr, "\nUsage: ./khugepaged <test type> [dir]\n\n"); + fprintf(stderr, "\nUsage: ./khugepaged [OPTIONS] <test type> [dir]\n\n"); fprintf(stderr, "\t<test type>\t: <context>:<mem_type>\n"); fprintf(stderr, "\t<context>\t: [all|khugepaged|madvise]\n"); fprintf(stderr, "\t<mem_type>\t: [all|anon|file|shmem]\n"); @@ -1085,15 +1092,34 @@ static void usage(void) fprintf(stderr, "\tCONFIG_READ_ONLY_THP_FOR_FS=y\n"); fprintf(stderr, "\n\tif [dir] is a (sub)directory of a tmpfs mount, tmpfs must be\n"); fprintf(stderr, "\tmounted with huge=madvise option for khugepaged tests to work\n"); + fprintf(stderr, "\n\tSupported Options:\n"); + fprintf(stderr, "\t\t-h: This help message.\n"); + fprintf(stderr, "\t\t-s: mTHP size, expressed as page order.\n"); + fprintf(stderr, "\t\t Defaults to 0. Use this size for anon allocations.\n"); exit(1); }
-static void parse_test_type(int argc, const char **argv) +static void parse_test_type(int argc, char **argv) { + int opt; char *buf; const char *token;
- if (argc == 1) { + while ((opt = getopt(argc, argv, "s:h")) != -1) { + switch (opt) { + case 's': + anon_order = atoi(optarg); + break; + case 'h': + default: + usage(); + } + } + + argv += optind; + argc -= optind; + + if (argc == 0) { /* Backwards compatibility */ khugepaged_context = &__khugepaged_context; madvise_context = &__madvise_context; @@ -1101,7 +1127,7 @@ static void parse_test_type(int argc, const char **argv) return; }
- buf = strdup(argv[1]); + buf = strdup(argv[0]); token = strsep(&buf, ":");
if (!strcmp(token, "all")) { @@ -1135,11 +1161,13 @@ static void parse_test_type(int argc, const char **argv) if (!file_ops) return;
- if (argc != 3) + if (argc != 2) usage(); + + get_finfo(argv[1]); }
-int main(int argc, const char **argv) +int main(int argc, char **argv) { int hpage_pmd_order; struct thp_settings default_settings = { @@ -1164,9 +1192,6 @@ int main(int argc, const char **argv)
parse_test_type(argc, argv);
- if (file_ops) - get_finfo(argv[2]); - setbuf(stdout, NULL);
page_size = getpagesize(); @@ -1183,6 +1208,7 @@ int main(int argc, const char **argv) default_settings.khugepaged.max_ptes_shared = hpage_pmd_nr / 2; default_settings.khugepaged.pages_to_scan = hpage_pmd_nr * 8; default_settings.hugepages[hpage_pmd_order].enabled = THP_INHERIT; + default_settings.hugepages[anon_order].enabled = THP_ALWAYS;
save_settings(); thp_push_settings(&default_settings); diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh index 3e2bc818d566..171c929826d5 100755 --- a/tools/testing/selftests/mm/run_vmtests.sh +++ b/tools/testing/selftests/mm/run_vmtests.sh @@ -347,6 +347,8 @@ CATEGORY="cow" run_test ./cow
CATEGORY="thp" run_test ./khugepaged
+CATEGORY="thp" run_test ./khugepaged -s 2 + CATEGORY="thp" run_test ./transhuge-stress -d 20
CATEGORY="thp" run_test ./split_huge_page_test