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authorYafang Shao <laoar.shao@gmail.com>2020-05-07 18:35:43 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-05-07 19:27:20 -0700
commit11d6761218d19ca06ae5387f4e3692c4fa9e7493 (patch)
tree3290a247cd155247a76c43735b9cec84f908d3ec
parentb5f2006144c6ae941726037120fa1001ddede784 (diff)
downloadlinux-stericsson-11d6761218d19ca06ae5387f4e3692c4fa9e7493.tar.gz
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 [akpm@linux-foundation.org: s/EBUSY/ENOSPC/, per Michal] [akpm@linux-foundation.org: s/EBUSY/ENOSPC/, per Michal] Fixes: 73f576c04b94 ("mm: memcontrol: fix cgroup creation failure after many small jobs") Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Link: http://lkml.kernel.org/r/20200407063621.GA18914@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1586192163-20099-1-git-send-email-laoar.shao@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memcontrol.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5beea03dd58a..a3b97f103966 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4990,19 +4990,22 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
unsigned int size;
int node;
int __maybe_unused i;
+ 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->vmstats_local = alloc_percpu(struct memcg_vmstats_percpu);
if (!memcg->vmstats_local)
@@ -5046,7 +5049,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
fail:
mem_cgroup_id_remove(memcg);
__mem_cgroup_free(memcg);
- return NULL;
+ return ERR_PTR(error);
}
static struct cgroup_subsys_state * __ref
@@ -5057,8 +5060,8 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
long error = -ENOMEM;
memcg = mem_cgroup_alloc();
- if (!memcg)
- return ERR_PTR(error);
+ if (IS_ERR(memcg))
+ return ERR_CAST(memcg);
WRITE_ONCE(memcg->high, PAGE_COUNTER_MAX);
memcg->soft_limit = PAGE_COUNTER_MAX;
@@ -5108,7 +5111,7 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
fail:
mem_cgroup_id_remove(memcg);
mem_cgroup_free(memcg);
- return ERR_PTR(-ENOMEM);
+ return ERR_PTR(error);
}
static int mem_cgroup_css_online(struct cgroup_subsys_state *css)