[merged] mm-memcg-charge-memcg-percpu-memory-to-the-parent-cgroup.patch removed from -mm tree

[merged] mm-memcg-charge-memcg-percpu-memory-to-the-parent-cgroup.patch removed from -mm tree

[akpm]

The patch titled
     Subject: mm: memcg: charge memcg percpu memory to the parent cgroup
has been removed from the -mm tree.  Its filename was
     mm-memcg-charge-memcg-percpu-memory-to-the-parent-cgroup.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Roman Gushchin <guro@fb.com>
Subject: mm: memcg: charge memcg percpu memory to the parent cgroup

Memory cgroups are using large chunks of percpu memory to store vmstat
data.  Yet this memory is not accounted at all, so in the case when there
are many (dying) cgroups, it's not exactly clear where all the memory is.

Because the size of memory cgroup internal structures can dramatically
exceed the size of object or page which is pinning it in the memory, it's
not a good idea to simply ignore it.  It actually breaks the isolation
between cgroups.

Let's account the consumed percpu memory to the parent cgroup.

[guro@fb.com: add WARN_ON_ONCE()s, per Johannes]
  Link: http://lkml.kernel.org/r/20200811170611.GB1507044@carbon.DHCP.thefacebook.com
Link: http://lkml.kernel.org/r/20200623184515.4132564-5-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
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: 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: Bixuan Cui <cuibixuan@huawei.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memcontrol.c |   20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

--- a/mm/memcontrol.c~mm-memcg-charge-memcg-percpu-memory-to-the-parent-cgroup
+++ a/mm/memcontrol.c
@@ -5131,13 +5131,18 @@ static int alloc_mem_cgroup_per_node_inf
 	if (!pn)
 		return 1;
 
-	pn->lruvec_stat_local = alloc_percpu(struct lruvec_stat);
+	/* We charge the parent cgroup, never the current task */
+	WARN_ON_ONCE(!current->active_memcg);
+
+	pn->lruvec_stat_local = alloc_percpu_gfp(struct lruvec_stat,
+						 GFP_KERNEL_ACCOUNT);
 	if (!pn->lruvec_stat_local) {
 		kfree(pn);
 		return 1;
 	}
 
-	pn->lruvec_stat_cpu = alloc_percpu(struct lruvec_stat);
+	pn->lruvec_stat_cpu = alloc_percpu_gfp(struct lruvec_stat,
+					       GFP_KERNEL_ACCOUNT);
 	if (!pn->lruvec_stat_cpu) {
 		free_percpu(pn->lruvec_stat_local);
 		kfree(pn);
@@ -5211,11 +5216,16 @@ static struct mem_cgroup *mem_cgroup_all
 		goto fail;
 	}
 
-	memcg->vmstats_local = alloc_percpu(struct memcg_vmstats_percpu);
+	/* We charge the parent cgroup, never the current task */
+	WARN_ON_ONCE(!current->active_memcg);
+
+	memcg->vmstats_local = alloc_percpu_gfp(struct memcg_vmstats_percpu,
+						GFP_KERNEL_ACCOUNT);
 	if (!memcg->vmstats_local)
 		goto fail;
 
-	memcg->vmstats_percpu = alloc_percpu(struct memcg_vmstats_percpu);
+	memcg->vmstats_percpu = alloc_percpu_gfp(struct memcg_vmstats_percpu,
+						 GFP_KERNEL_ACCOUNT);
 	if (!memcg->vmstats_percpu)
 		goto fail;
 
@@ -5264,7 +5274,9 @@ mem_cgroup_css_alloc(struct cgroup_subsy
 	struct mem_cgroup *memcg;
 	long error = -ENOMEM;
 
+	memalloc_use_memcg(parent);
 	memcg = mem_cgroup_alloc();
+	memalloc_unuse_memcg();
 	if (IS_ERR(memcg))
 		return ERR_CAST(memcg);
 
_

Patches currently in -mm which might be from guro@fb.com are

mm-vmstat-fix-proc-sys-vm-stat_refresh-generating-false-warnings.patch
mm-vmstat-fix-proc-sys-vm-stat_refresh-generating-false-warnings-fix.patch