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author | Tejun Heo <tj@kernel.org> | 2016-04-21 23:06:48 (GMT) |
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committer | Tejun Heo <tj@kernel.org> | 2016-04-25 19:45:14 (GMT) |
commit | 5cf1cacb49aee39c3e02ae87068fc3c6430659b0 (patch) | |
tree | 569518d16093a55169e4ef1cd5399e9a3f620d06 /kernel/notifier.c | |
parent | bcc981e9ed84c678533299d7eff17d2c81e4d5de (diff) | |
download | linux-5cf1cacb49aee39c3e02ae87068fc3c6430659b0.tar.xz |
cgroup, cpuset: replace cpuset_post_attach_flush() with cgroup_subsys->post_attach callback
Since e93ad19d0564 ("cpuset: make mm migration asynchronous"), cpuset
kicks off asynchronous NUMA node migration if necessary during task
migration and flushes it from cpuset_post_attach_flush() which is
called at the end of __cgroup_procs_write(). This is to avoid
performing migration with cgroup_threadgroup_rwsem write-locked which
can lead to deadlock through dependency on kworker creation.
memcg has a similar issue with charge moving, so let's convert it to
an official callback rather than the current one-off cpuset specific
function. This patch adds cgroup_subsys->post_attach callback and
makes cpuset register cpuset_post_attach_flush() as its ->post_attach.
The conversion is mostly one-to-one except that the new callback is
called under cgroup_mutex. This is to guarantee that no other
migration operations are started before ->post_attach callbacks are
finished. cgroup_mutex is one of the outermost mutex in the system
and has never been and shouldn't be a problem. We can add specialized
synchronization around __cgroup_procs_write() but I don't think
there's any noticeable benefit.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org> # 4.4+ prerequisite for the next patch
Diffstat (limited to 'kernel/notifier.c')
0 files changed, 0 insertions, 0 deletions