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| author | Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> | 2012-10-04 16:37:16 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-10-28 10:14:14 -0700 |
| commit | 9a55fef20afb3d7362b0c9d19ba1e78dfe482d3d (patch) | |
| tree | ee17e4fd3a8b21aa09e66d5bca06bbe349d122b3 | |
| parent | 9b1ca55bf3ff5fa1c3ff87bac9c7183bc421dc82 (diff) | |
| download | lwn-9a55fef20afb3d7362b0c9d19ba1e78dfe482d3d.tar.gz lwn-9a55fef20afb3d7362b0c9d19ba1e78dfe482d3d.zip | |
cgroup: notify_on_release may not be triggered in some cases
commit 1f5320d5972aa50d3e8d2b227b636b370e608359 upstream.
notify_on_release must be triggered when the last process in a cgroup is
move to another. But if the first(and only) process in a cgroup is moved to
another, notify_on_release is not triggered.
# mkdir /cgroup/cpu/SRC
# mkdir /cgroup/cpu/DST
#
# echo 1 >/cgroup/cpu/SRC/notify_on_release
# echo 1 >/cgroup/cpu/DST/notify_on_release
#
# sleep 300 &
[1] 8629
#
# echo 8629 >/cgroup/cpu/SRC/tasks
# echo 8629 >/cgroup/cpu/DST/tasks
-> notify_on_release for /SRC must be triggered at this point,
but it isn't.
This is because put_css_set() is called before setting CGRP_RELEASABLE
in cgroup_task_migrate(), and is a regression introduce by the
commit:74a1166d(cgroups: make procs file writable), which was merged
into v3.0.
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Ben Blum <bblum@andrew.cmu.edu>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/cgroup.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index ed64ccac67c9..b76dd5862a8c 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1868,9 +1868,8 @@ static void cgroup_task_migrate(struct cgroup *cgrp, struct cgroup *oldcgrp, * trading it for newcg is protected by cgroup_mutex, we're safe to drop * it here; it will be freed under RCU. */ - put_css_set(oldcg); - set_bit(CGRP_RELEASABLE, &oldcgrp->flags); + put_css_set(oldcg); } /** |