From c8b90731427814b1e265c3c2bc01c38406963c32 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 5 Oct 2023 09:39:21 -0700 Subject: selftests/mm: export get_free_hugepages() Patch series "New selftest for mm", v2. This is a simple test case that reproduces an mm problem[1], where a page fault races with madvise(), and it is not trivial to reproduce and debug. This test-case aims to avoid such race problems from happening again, impacting workloads that leverages external allocators, such as tcmalloc, jemalloc, etc. [1] https://lore.kernel.org/all/20231001005659.2185316-1-riel@surriel.com/#r This patch (of 2): get_free_hugepages() is helpful for other hugepage tests. Export it to the common file (vm_util.c) to be reused. Link: https://lkml.kernel.org/r/20231005163922.87568-1-leitao@debian.org Link: https://lkml.kernel.org/r/20231005163922.87568-2-leitao@debian.org Signed-off-by: Breno Leitao Reviewed-by: Rik van Riel Cc: Mike Kravetz Cc: Muchun Song Signed-off-by: Andrew Morton --- tools/testing/selftests/mm/vm_util.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'tools/testing/selftests/mm/vm_util.c') diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c index 558c9cd8901c..3082b40492dd 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -269,3 +269,22 @@ int uffd_unregister(int uffd, void *addr, uint64_t len) return ret; } + +unsigned long get_free_hugepages(void) +{ + unsigned long fhp = 0; + char *line = NULL; + size_t linelen = 0; + FILE *f = fopen("/proc/meminfo", "r"); + + if (!f) + return fhp; + while (getline(&line, &linelen, f) > 0) { + if (sscanf(line, "HugePages_Free: %lu", &fhp) == 1) + break; + } + + free(line); + fclose(f); + return fhp; +} -- cgit v1.2.3-59-g8ed1b