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kselftests: cgroup: add perpcu memory accounting test 

Add a simple test to check the percpu memory accounting.  The test creates
a cgroup tree with 1000 child cgroups and checks values of memory.current
and memory.stat::percpu.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Tobin C. Harding <tobin@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Bixuan Cui <cuibixuan@huawei.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: http://lkml.kernel.org/r/20200608230819.832349-6-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Roman Gushchin 2020-08-11 18:30:29 -07:00 committed by Linus Torvalds
parent 3e38e0aaca
commit 90631e1dea
1 changed files with 69 additions and 1 deletions
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70
tools/testing/selftests/cgroup/test_kmem.c
View File

@ -18,6 +18,15 @@
#include "cgroup_util.h"
/*
* Memory cgroup charging and vmstat data aggregation is performed using
* percpu batches 32 pages big (look at MEMCG_CHARGE_BATCH). So the maximum
* discrepancy between charge and vmstat entries is number of cpus multiplied
* by 32 pages multiplied by 2.
*/
#define MAX_VMSTAT_ERROR (4096 * 32 * 2 * get_nprocs())
static int alloc_dcache(const char *cgroup, void *arg)
{
unsigned long i;
@ -180,7 +189,7 @@ static int test_kmem_memcg_deletion(const char *root)
goto cleanup;
sum = slab + anon + file + kernel_stack;
if (abs(sum - current) < 4096 * 32 * 2 * get_nprocs()) {
if (abs(sum - current) < MAX_VMSTAT_ERROR) {
ret = KSFT_PASS;
} else {
printf("memory.current = %ld\n", current);
@ -331,6 +340,64 @@ cleanup:
return ret;
}
/*
* This test creates a sub-tree with 1000 memory cgroups.
* Then it checks that the memory.current on the parent level
* is greater than 0 and approximates matches the percpu value
* from memory.stat.
*/
static int test_percpu_basic(const char *root)
{
int ret = KSFT_FAIL;
char *parent, *child;
long current, percpu;
int i;
parent = cg_name(root, "percpu_basic_test");
if (!parent)
goto cleanup;
if (cg_create(parent))
goto cleanup;
if (cg_write(parent, "cgroup.subtree_control", "+memory"))
goto cleanup;
for (i = 0; i < 1000; i++) {
child = cg_name_indexed(parent, "child", i);
if (!child)
return -1;
if (cg_create(child))
goto cleanup_children;
free(child);
}
current = cg_read_long(parent, "memory.current");
percpu = cg_read_key_long(parent, "memory.stat", "percpu ");
if (current > 0 && percpu > 0 && abs(current - percpu) <
MAX_VMSTAT_ERROR)
ret = KSFT_PASS;
else
printf("memory.current %ld\npercpu %ld\n",
current, percpu);
cleanup_children:
for (i = 0; i < 1000; i++) {
child = cg_name_indexed(parent, "child", i);
cg_destroy(child);
free(child);
}
cleanup:
cg_destroy(parent);
free(parent);
return ret;
}
#define T(x) { x, #x }
struct kmem_test {
int (*fn)(const char *root);
@ -341,6 +408,7 @@ struct kmem_test {
T(test_kmem_proc_kpagecgroup),
T(test_kmem_kernel_stacks),
T(test_kmem_dead_cgroups),
T(test_percpu_basic),
};
#undef T