From: Tejun Heo Date: Fri, 29 Nov 2013 15:42:59 +0000 (-0500) Subject: cgroup: remove cgroup_pidlist->rwsem X-Git-Tag: v3.14-rc1~136^2~28 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=069df3b7aeb3f4e926c4da9630c92010909af512;p=pandora-kernel.git cgroup: remove cgroup_pidlist->rwsem cgroup_pidlist locking is needlessly complicated. It has outer cgroup->pidlist_mutex to protect the list of pidlists associated with a cgroup and then each pidlist has rwsem to synchronize updates and reads. Given that the only read access is from seq_file operations which are always invoked back-to-back, the rwsem is a giant overkill. All it does is adding unnecessary complexity. This patch removes cgroup_pidlist->rwsem and protects all accesses to pidlists belonging to a cgroup with cgroup->pidlist_mutex. pidlist->rwsem locking is removed if it's nested inside cgroup->pidlist_mutex; otherwise, it's replaced with cgroup->pidlist_mutex locking. Signed-off-by: Tejun Heo Acked-by: Li Zefan --- Reading git-diff-tree failed