Commit 9330694d authored by Zach O'Keefe's avatar Zach O'Keefe Committed by Andrew Morton
Browse files

selftests/vm: add MADV_COLLAPSE collapse context to selftests 

Add madvise collapse context to hugepage collapse selftests.  This context
is tested with /sys/kernel/mm/transparent_hugepage/enabled set to "never"
in order to avoid unwanted interaction with khugepaged during testing.

Also, refactor updates to sysfs THP settings using a stack so that the THP
settings from nested callers can be restored.

Link: https://lkml.kernel.org/r/20220706235936.2197195-17-zokeefe@google.com


Signed-off-by: default avatarZach O'Keefe <zokeefe@google.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Chris Kennelly <ckennelly@google.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Souptick Joarder (HPE)" <jrdr.linux@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent be6667b0

tools/testing/selftests/vm/khugepaged.c

+125 −46
Original line number Diff line number Diff line
@@ -14,6 +14,9 @@ 
#ifndef MADV_PAGEOUT

#define MADV_PAGEOUT 21

#endif

#ifndef MADV_COLLAPSE

#define MADV_COLLAPSE 25

#endif



#define BASE_ADDR ((void *)(1UL << 30))

static unsigned long hpage_pmd_size;
@@ -95,18 +98,6 @@ struct settings { 
	struct khugepaged_settings khugepaged;

};



static struct settings default_settings = {

	.thp_enabled = THP_MADVISE,

	.thp_defrag = THP_DEFRAG_ALWAYS,

	.shmem_enabled = SHMEM_NEVER,

	.use_zero_page = 0,

	.khugepaged = {

		.defrag = 1,

		.alloc_sleep_millisecs = 10,

		.scan_sleep_millisecs = 10,

	},

};



static struct settings saved_settings;

static bool skip_settings_restore;
@@ -284,6 +275,39 @@ static void write_settings(struct settings *settings) 
	write_num("khugepaged/pages_to_scan", khugepaged->pages_to_scan);

}



#define MAX_SETTINGS_DEPTH 4

static struct settings settings_stack[MAX_SETTINGS_DEPTH];

static int settings_index;



static struct settings *current_settings(void)

{

	if (!settings_index) {

		printf("Fail: No settings set");

		exit(EXIT_FAILURE);

	}

	return settings_stack + settings_index - 1;

}



static void push_settings(struct settings *settings)

{

	if (settings_index >= MAX_SETTINGS_DEPTH) {

		printf("Fail: Settings stack exceeded");

		exit(EXIT_FAILURE);

	}

	settings_stack[settings_index++] = *settings;

	write_settings(current_settings());

}



static void pop_settings(void)

{

	if (settings_index <= 0) {

		printf("Fail: Settings stack empty");

		exit(EXIT_FAILURE);

	}

	--settings_index;

	write_settings(current_settings());

}



static void restore_settings(int sig)

{

	if (skip_settings_restore)
@@ -327,14 +351,6 @@ static void save_settings(void) 
	signal(SIGQUIT, restore_settings);

}



static void adjust_settings(void)

{



	printf("Adjust settings...");

	write_settings(&default_settings);

	success("OK");

}



#define MAX_LINE_LENGTH 500



static bool check_for_pattern(FILE *fp, char *pattern, char *buf)
@@ -493,6 +509,38 @@ static void validate_memory(int *p, unsigned long start, unsigned long end) 
	}

}



static void madvise_collapse(const char *msg, char *p, bool expect)

{

	int ret;

	struct settings settings = *current_settings();



	printf("%s...", msg);

	/* Sanity check */

	if (check_huge(p)) {

		printf("Unexpected huge page\n");

		exit(EXIT_FAILURE);

	}



	/*

	 * Prevent khugepaged interference and tests that MADV_COLLAPSE

	 * ignores /sys/kernel/mm/transparent_hugepage/enabled

	 */

	settings.thp_enabled = THP_NEVER;

	push_settings(&settings);



	/* Clear VM_NOHUGEPAGE */

	madvise(p, hpage_pmd_size, MADV_HUGEPAGE);

	ret = madvise(p, hpage_pmd_size, MADV_COLLAPSE);

	if (((bool)ret) == expect)

		fail("Fail: Bad return value");

	else if (check_huge(p) != expect)

		fail("Fail: check_huge()");

	else

		success("OK");



	pop_settings();

}



#define TICK 500000

static bool wait_for_scan(const char *msg, char *p)

{
@@ -542,11 +590,11 @@ static void khugepaged_collapse(const char *msg, char *p, bool expect) 


static void alloc_at_fault(void)

{

	struct settings settings = default_settings;

	struct settings settings = *current_settings();

	char *p;



	settings.thp_enabled = THP_ALWAYS;

	write_settings(&settings);

	push_settings(&settings);



	p = alloc_mapping();

	*p = 1;
@@ -556,7 +604,7 @@ static void alloc_at_fault(void) 
	else

		fail("Fail");



	write_settings(&default_settings);

	pop_settings();



	madvise(p, page_size, MADV_DONTNEED);

	printf("Split huge PMD on MADV_DONTNEED...");
@@ -602,11 +650,11 @@ static void collapse_single_pte_entry(struct collapse_context *c) 
static void collapse_max_ptes_none(struct collapse_context *c)

{

	int max_ptes_none = hpage_pmd_nr / 2;

	struct settings settings = default_settings;

	struct settings settings = *current_settings();

	void *p;



	settings.khugepaged.max_ptes_none = max_ptes_none;

	write_settings(&settings);

	push_settings(&settings);



	p = alloc_mapping();
@@ -623,7 +671,7 @@ static void collapse_max_ptes_none(struct collapse_context *c) 
	}



	munmap(p, hpage_pmd_size);

	write_settings(&default_settings);

	pop_settings();

}



static void collapse_swapin_single_pte(struct collapse_context *c)
@@ -703,7 +751,6 @@ static void collapse_single_pte_entry_compound(struct collapse_context *c) 


	p = alloc_hpage();

	madvise(p, hpage_pmd_size, MADV_NOHUGEPAGE);



	printf("Split huge page leaving single PTE mapping compound page...");

	madvise(p + page_size, hpage_pmd_size - page_size, MADV_DONTNEED);

	if (!check_huge(p))
@@ -864,7 +911,7 @@ static void collapse_fork_compound(struct collapse_context *c) 
		c->collapse("Collapse PTE table full of compound pages in child",

			    p, true);

		write_num("khugepaged/max_ptes_shared",

			  default_settings.khugepaged.max_ptes_shared);

			  current_settings()->khugepaged.max_ptes_shared);



		validate_memory(p, 0, hpage_pmd_size);

		munmap(p, hpage_pmd_size);
@@ -943,9 +990,21 @@ static void collapse_max_ptes_shared(struct collapse_context *c) 
	munmap(p, hpage_pmd_size);

}



int main(void)

int main(int argc, const char **argv)

{

	struct collapse_context c;

	struct settings default_settings = {

		.thp_enabled = THP_MADVISE,

		.thp_defrag = THP_DEFRAG_ALWAYS,

		.shmem_enabled = SHMEM_NEVER,

		.use_zero_page = 0,

		.khugepaged = {

			.defrag = 1,

			.alloc_sleep_millisecs = 10,

			.scan_sleep_millisecs = 10,

		},

	};

	const char *tests = argc == 1 ? "all" : argv[1];



	setbuf(stdout, NULL);
@@ -959,10 +1018,11 @@ int main(void) 
	default_settings.khugepaged.pages_to_scan = hpage_pmd_nr * 8;



	save_settings();

	adjust_settings();

	push_settings(&default_settings);



	alloc_at_fault();



	if (!strcmp(tests, "khugepaged") || !strcmp(tests, "all")) {

		printf("\n*** Testing context: khugepaged ***\n");

		c.collapse = &khugepaged_collapse;

		c.enforce_pte_scan_limits = true;
@@ -979,6 +1039,25 @@ int main(void) 
		collapse_fork(&c);

		collapse_fork_compound(&c);

		collapse_max_ptes_shared(&c);

	}

	if (!strcmp(tests, "madvise") || !strcmp(tests, "all")) {

		printf("\n*** Testing context: madvise ***\n");

		c.collapse = &madvise_collapse;

		c.enforce_pte_scan_limits = false;



		collapse_full(&c);

		collapse_empty(&c);

		collapse_single_pte_entry(&c);

		collapse_max_ptes_none(&c);

		collapse_swapin_single_pte(&c);

		collapse_max_ptes_swap(&c);

		collapse_single_pte_entry_compound(&c);

		collapse_full_of_compound(&c);

		collapse_compound_extreme(&c);

		collapse_fork(&c);

		collapse_fork_compound(&c);

		collapse_max_ptes_shared(&c);

	}



	restore_settings(0);

}