]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
mm, memcg: fix error return value of mem_cgroup_css_alloc()
authorYafang Shao <laoar.shao@gmail.com>
Fri, 8 May 2020 01:35:43 +0000 (18:35 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 8 May 2020 02:27:20 +0000 (19:27 -0700)
commit11d6761218d19ca06ae5387f4e3692c4fa9e7493
tree3290a247cd155247a76c43735b9cec84f908d3ec
parentb5f2006144c6ae941726037120fa1001ddede784
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>
mm/memcontrol.c