kselftests: cgroup: update kmem test precision tolerance

1813e51eec ("memcg: increase MEMCG_CHARGE_BATCH to 64") has changed
the batch size while this test case has been left behind. This has led
to a test failure reported by test bot:
not ok 2 selftests: cgroup: test_kmem # exit=1

Update the tolerance for the pcp charges to reflect the
MEMCG_CHARGE_BATCH change to fix this.

[akpm@linux-foundation.org: update comments, per Roman]
Link: https://lkml.kernel.org/r/Y4m8Unt6FhWKC6IH@dhcp22.suse.cz
Fixes: 1813e51eec ("memcg: increase MEMCG_CHARGE_BATCH to 64")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: kernel test robot <yujie.liu@intel.com>
  Link: https://lore.kernel.org/oe-lkp/202212010958.c1053bd3-yujie.liu@intel.com
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Tested-by: Yujie Liu <yujie.liu@intel.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Michal Hocko 2022-12-02 09:50:26 +01:00 committed by Andrew Morton
parent f5ad508340
commit de16d6e4a9

View File

@ -19,12 +19,12 @@
/*
* Memory cgroup charging is performed using percpu batches 32 pages
* Memory cgroup charging is performed using percpu batches 64 pages
* big (look at MEMCG_CHARGE_BATCH), whereas memory.stat is exact. So
* the maximum discrepancy between charge and vmstat entries is number
* of cpus multiplied by 32 pages.
* of cpus multiplied by 64 pages.
*/
#define MAX_VMSTAT_ERROR (4096 * 32 * get_nprocs())
#define MAX_VMSTAT_ERROR (4096 * 64 * get_nprocs())
static int alloc_dcache(const char *cgroup, void *arg)