[PATCH mm v5 6/9] memcg: enable accounting for percpu allocation of struct cgroup_rstat_cpu

Vasily Averin
2022-06-23T14:51:37Z

struct cgroup_rstat_cpu is percpu allocated for each new cgroup and
can consume a significant portion of all allocated memory on nodes
with a large number of CPUs.

Common part of the cgroup creation:
Allocs Alloc $1*$2 Sum Allocation
number size
--------------------------------------------
16 ~ 352 5632 5632 KERNFS
1 + 4096 4096 9728 (cgroup_mkdir+0xe4)
1 584 584 10312 (radix_tree_node_alloc.constprop.0+0x89)
1 192 192 10504 (__d_alloc+0x29)
2 72 144 10648 (avc_alloc_node+0x27)
2 64 128 10776 (percpu_ref_init+0x6a)
1 64 64 10840 (memcg_list_lru_alloc+0x21a)
percpu:
1 + 192 192 192 call_site=psi_cgroup_alloc+0x1e
1 + 96 96 288 call_site=cgroup_rstat_init+0x5f
2 12 24 312 call_site=percpu_ref_init+0x23
1 6 6 318 call_site=__percpu_counter_init+0x22

'+' -- to be accounted,
'~' -- partially accounted

Signed-off-by: Vasily Averin <vvs-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>
Acked-by: Shakeel Butt <shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Acked-by: Roman Gushchin <roman.gushchin-fxUVXftIFDnyG1zEObXtfA@public.gmane.org>
Acked-by: Muchun Song <songmuchun-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>
---
kernel/cgroup/rstat.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
index 24b5c2ab5598..2904b185b01b 100644
--- a/kernel/cgroup/rstat.c
+++ b/kernel/cgroup/rstat.c
@@ -257,7 +257,8 @@ int cgroup_rstat_init(struct cgroup *cgrp)

/* the root cgrp has rstat_cpu preallocated */
if (!cgrp->rstat_cpu) {
- cgrp->rstat_cpu = alloc_percpu(struct cgroup_rstat_cpu);
+ cgrp->rstat_cpu = alloc_percpu_gfp(struct cgroup_rstat_cpu,
+ GFP_KERNEL_ACCOUNT);
if (!cgrp->rstat_cpu)
return -ENOMEM;
}
--
2.36.1