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: Mike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
This commit is contained in:
Mike Rapoport 2018-05-15 19:05:53 +03:00 committed by Shuah Khan (Samsung OSG)
parent 84092dbcf9
commit 478b27844e
3 changed files with 108 additions and 0 deletions

View File

@ -315,3 +315,19 @@ int alloc_anon(const char *cgroup, void *arg)
free(buf); free(buf);
return 0; 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;
}

View File

@ -38,3 +38,4 @@ extern int cg_run_nowait(const char *cgroup,
extern int get_temp_fd(void); extern int get_temp_fd(void);
extern int alloc_pagecache(int fd, size_t size); extern int alloc_pagecache(int fd, size_t size);
extern int alloc_anon(const char *cgroup, void *arg); extern int alloc_anon(const char *cgroup, void *arg);
extern int is_swap_enabled(void);

View File

@ -638,6 +638,96 @@ static int test_memcg_max(const char *root)
return ret; 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 * This test disables swapping and tries to allocate anonymous memory
* up to OOM. Then it checks for oom and oom_kill events in * 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_high),
T(test_memcg_max), T(test_memcg_max),
T(test_memcg_oom_events), T(test_memcg_oom_events),
T(test_memcg_swap_max),
}; };
#undef T #undef T