diff options
| author | Roman Gushchin <guro@fb.com> | 2019-04-19 10:03:03 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-31 06:46:19 -0700 |
| commit | 4e4d5cea79a7ec06844981b1db87d431bddcf50b (patch) | |
| tree | 2aa57875176f1a258345364ab9f221eb2c72c3e5 /include/linux/seqlock.h | |
| parent | 944c58523731c1a791d324536baf3a1ff2c34f1f (diff) | |
cgroup: protect cgroup->nr_(dying_)descendants by css_set_lock
[ Upstream commit 4dcabece4c3a9f9522127be12cc12cc120399b2f ]
The number of descendant cgroups and the number of dying
descendant cgroups are currently synchronized using the cgroup_mutex.
The number of descendant cgroups will be required by the cgroup v2
freezer, which will use it to determine if a cgroup is frozen
(depending on total number of descendants and number of frozen
descendants). It's not always acceptable to grab the cgroup_mutex,
especially from quite hot paths (e.g. exit()).
To avoid this, let's additionally synchronize these counters using
the css_set_lock.
So, it's safe to read these counters with either cgroup_mutex or
css_set_lock locked, and for changing both locks should be acquired.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: kernel-team@fb.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include/linux/seqlock.h')
0 files changed, 0 insertions, 0 deletions