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authorTejun Heo <tj@kernel.org>2013-05-24 10:55:38 +0900
committerTejun Heo <tj@kernel.org>2013-05-24 10:55:38 +0900
commitd591fb56618f4f93160b477dfa25bbb1e31b0e85 (patch)
treef84721d586f927bb83ac9a1ae69cfc42b4380f3a /kernel
parent75501a6d59e989e5c286716e5b3b66ace4660e83 (diff)
downloadlinux-d591fb56618f4f93160b477dfa25bbb1e31b0e85.tar.bz2
device_cgroup: simplify cgroup tree walk in propagate_exception()
During a config change, propagate_exception() needs to traverse the subtree to update config on the subtree. Because such config updates need to allocate memory, it couldn't directly use cgroup_for_each_descendant_pre() which required the whole iteration to be contained in a single RCU read critical section. To work around the limitation, propagate_exception() built a linked list of descendant cgroups while read-locking RCU and then walked the list afterwards, which is safe as the whole iteration is protected by devcgroup_mutex. This works but is cumbersome. With the recent updates, cgroup iterators now allow dropping RCU read lock while iteration is in progress making this workaround no longer necessary. This patch replaces dev_cgroup->propagate_pending list and get_online_devcg() with direct cgroup_for_each_descendant_pre() walk. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Aristeu Rozanski <aris@redhat.com> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz>
Diffstat (limited to 'kernel')
0 files changed, 0 insertions, 0 deletions