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Commit 478b2784 authored by Mike Rapoport's avatar Mike Rapoport Committed by Shuah Khan (Samsung OSG)
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selftests: cgroup/memcontrol: add basic test for swap controls 



The new test verifies that memory.swap.max and memory.swap.current behave
as expected for simple allocation scenarios

Signed-off-by: default avatarMike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarRoman Gushchin <guro@fb.com>
Signed-off-by: default avatarShuah Khan (Samsung OSG) <shuah@kernel.org>
parent 84092dbc

tools/testing/selftests/cgroup/cgroup_util.c

+16 −0
Original line number Diff line number Diff line
@@ -315,3 +315,19 @@ int alloc_anon(const char *cgroup, void *arg) 
	free(buf);

	return 0;

}



int is_swap_enabled(void)

{

	char buf[PAGE_SIZE];

	const char delim[] = "\n";

	int cnt = 0;

	char *line;



	if (read_text("/proc/swaps", buf, sizeof(buf)) <= 0)

		return -1;



	for (line = strtok(buf, delim); line; line = strtok(NULL, delim))

		cnt++;



	return cnt > 1;

}

tools/testing/selftests/cgroup/cgroup_util.h

+1 −0
Original line number Diff line number Diff line
@@ -38,3 +38,4 @@ extern int cg_run_nowait(const char *cgroup, 
extern int get_temp_fd(void);

extern int alloc_pagecache(int fd, size_t size);

extern int alloc_anon(const char *cgroup, void *arg);

extern int is_swap_enabled(void);

tools/testing/selftests/cgroup/test_memcontrol.c

+91 −0
Original line number Diff line number Diff line
@@ -638,6 +638,96 @@ static int test_memcg_max(const char *root) 
	return ret;

}



static int alloc_anon_50M_check_swap(const char *cgroup, void *arg)

{

	long mem_max = (long)arg;

	size_t size = MB(50);

	char *buf, *ptr;

	long mem_current, swap_current;

	int ret = -1;



	buf = malloc(size);

	for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)

		*ptr = 0;



	mem_current = cg_read_long(cgroup, "memory.current");

	if (!mem_current || !values_close(mem_current, mem_max, 3))

		goto cleanup;



	swap_current = cg_read_long(cgroup, "memory.swap.current");

	if (!swap_current ||

	    !values_close(mem_current + swap_current, size, 3))

		goto cleanup;



	ret = 0;

cleanup:

	free(buf);

	return ret;

}



/*

 * This test checks that memory.swap.max limits the amount of

 * anonymous memory which can be swapped out.

 */

static int test_memcg_swap_max(const char *root)

{

	int ret = KSFT_FAIL;

	char *memcg;

	long max;



	if (!is_swap_enabled())

		return KSFT_SKIP;



	memcg = cg_name(root, "memcg_test");

	if (!memcg)

		goto cleanup;



	if (cg_create(memcg))

		goto cleanup;



	if (cg_read_long(memcg, "memory.swap.current")) {

		ret = KSFT_SKIP;

		goto cleanup;

	}



	if (cg_read_strcmp(memcg, "memory.max", "max\n"))

		goto cleanup;



	if (cg_read_strcmp(memcg, "memory.swap.max", "max\n"))

		goto cleanup;



	if (cg_write(memcg, "memory.swap.max", "30M"))

		goto cleanup;



	if (cg_write(memcg, "memory.max", "30M"))

		goto cleanup;



	/* Should be killed by OOM killer */

	if (!cg_run(memcg, alloc_anon, (void *)MB(100)))

		goto cleanup;



	if (cg_read_key_long(memcg, "memory.events", "oom ") != 1)

		goto cleanup;



	if (cg_read_key_long(memcg, "memory.events", "oom_kill ") != 1)

		goto cleanup;



	if (cg_run(memcg, alloc_anon_50M_check_swap, (void *)MB(30)))

		goto cleanup;



	max = cg_read_key_long(memcg, "memory.events", "max ");

	if (max <= 0)

		goto cleanup;



	ret = KSFT_PASS;



cleanup:

	cg_destroy(memcg);

	free(memcg);



	return ret;

}



/*

 * This test disables swapping and tries to allocate anonymous memory

 * up to OOM. Then it checks for oom and oom_kill events in
@@ -694,6 +784,7 @@ struct memcg_test { 
	T(test_memcg_high),

	T(test_memcg_max),

	T(test_memcg_oom_events),

	T(test_memcg_swap_max),

};

#undef T