Commit c8b90731 authored by Breno Leitao's avatar Breno Leitao Committed by Andrew Morton
Browse files

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: default avatarBreno Leitao <leitao@debian.org>
Reviewed-by: default avatarRik van Riel <riel@surriel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent afb2d666

tools/testing/selftests/mm/hugetlb-madvise.c

+0 −19
Original line number Diff line number Diff line
@@ -36,25 +36,6 @@ 
unsigned long huge_page_size;

unsigned long base_page_size;



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;

}



void write_fault_pages(void *addr, unsigned long nr_pages)

{

	unsigned long i;

tools/testing/selftests/mm/vm_util.c

+19 −0
Original line number Diff line number Diff line
@@ -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;

}

tools/testing/selftests/mm/vm_util.h

+1 −0
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ int uffd_register(int uffd, void *addr, uint64_t len, 
int uffd_unregister(int uffd, void *addr, uint64_t len);

int uffd_register_with_ioctls(int uffd, void *addr, uint64_t len,

			      bool miss, bool wp, bool minor, uint64_t *ioctls);

unsigned long get_free_hugepages(void);



/*

 * On ppc64 this will only work with radix 2M hugepage size