From: Tejun Heo Date: Thu, 13 Jun 2013 04:04:54 +0000 (-0700) Subject: cgroup: drop unnecessary RCU dancing from __put_css_set() X-Git-Tag: omap-for-v3.11/fixes-for-merge-window~44^2~30 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ddd69148bdc45e5e3e55bfde3571daecd5a96d75;p=pandora-kernel.git cgroup: drop unnecessary RCU dancing from __put_css_set() __put_css_set() does RCU read access on @cgrp across dropping @cgrp->count so that it can continue accessing @cgrp even if the count reached zero and destruction of the cgroup commenced. Given that both sides - __css_put() and cgroup_destroy_locked() - are cold paths, this is unnecessary. Just making cgroup_destroy_locked() grab css_set_lock while checking @cgrp->count is enough. Remove the RCU read locking from __put_css_set() and make cgroup_destroy_locked() read-lock css_set_lock when checking @cgrp->count. This will also allow removing @cgrp->count. Signed-off-by: Tejun Heo Acked-by: Li Zefan --- Reading git-diff-tree failed