The commit is pushed to "branch-rh7-3.10.0-1160.108.1.vz7.221.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-1160.108.1.vz7.221.1
------>
commit bad18b9592a632bc81270adb4a80000fdfd333a7
Author: Yafang Shao <laoar.s...@gmail.com>
Date: Thu May 7 18:35:43 2020 -0700
ms/mm, memcg: fix error return value of mem_cgroup_css_alloc()
When I run my memcg testcase which creates lots of memcgs, I found
there're unexpected out of memory logs while there're still enough
available free memory. The error log is
mkdir: cannot create directory 'foo.65533': Cannot allocate memory
The reason is when we try to create more than MEM_CGROUP_ID_MAX memcgs,
an -ENOMEM errno will be set by mem_cgroup_css_alloc(), but the right
errno should be -ENOSPC "No space left on device", which is an
appropriate errno for userspace's failed mkdir.
As the errno really misled me, we should make it right. After this
patch, the error log will be
mkdir: cannot create directory 'foo.65533': No space left on device
[a...@linux-foundation.org: s/EBUSY/ENOSPC/, per Michal]
[a...@linux-foundation.org: s/EBUSY/ENOSPC/, per Michal]
mFixes: 73f576c04b94 ("mm: memcontrol: fix cgroup creation failure after
many small jobs")
Suggested-by: Matthew Wilcox <wi...@infradead.org>
Signed-off-by: Yafang Shao <laoar.s...@gmail.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Acked-by: Michal Hocko <mho...@kernel.org>
Acked-by: Johannes Weiner <han...@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov....@gmail.com>
Link: http://lkml.kernel.org/r/20200407063621.ga18...@dhcp22.suse.cz
Link:
http://lkml.kernel.org/r/1586192163-20099-1-git-send-email-laoar.s...@gmail.com
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
https://virtuozzo.atlassian.net/browse/PSBM-153598
(cherry picked from commit 11d6761218d19ca06ae5387f4e3692c4fa9e7493)
Signed-off-by: Konstantin Khorenko <khore...@virtuozzo.com>
---
mm/memcontrol.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 80eda9c802b9..f173322fb44e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6751,19 +6751,22 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
size_t size;
int i, ret;
int node;
+ long error = -ENOMEM;
size = sizeof(struct mem_cgroup);
size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
memcg = kzalloc(size, GFP_KERNEL);
if (!memcg)
- return NULL;
+ return ERR_PTR(error);
memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,
1, MEM_CGROUP_ID_MAX,
GFP_KERNEL);
- if (memcg->id.id < 0)
+ if (memcg->id.id < 0) {
+ error = memcg->id.id;
goto fail;
+ }
memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
if (!memcg->stat)
@@ -6794,7 +6797,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
mem_cgroup_id_remove(memcg);
fail:
kfree(memcg);
- return NULL;
+ return ERR_PTR(error);
}
/*
@@ -6892,11 +6895,10 @@ static struct cgroup_subsys_state * __ref
mem_cgroup_css_alloc(struct cgroup *cont)
{
struct mem_cgroup *memcg;
- long error = -ENOMEM;
memcg = mem_cgroup_alloc();
- if (!memcg)
- return ERR_PTR(error);
+ if (IS_ERR(memcg))
+ return ERR_CAST(memcg);
/* root ? */
if (cont->parent == NULL) {
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