From: Tejun Heo Date: Mon, 21 Nov 2011 20:32:25 +0000 (-0800) Subject: cgroup_freezer: prepare for removal of TIF_FREEZE X-Git-Tag: v3.3-rc1~148^2~24^2~11 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=22b4e111fa01a1147aa562ceaf18a752a928ef4e;p=pandora-kernel.git cgroup_freezer: prepare for removal of TIF_FREEZE TIF_FREEZE will be removed soon and freezing() will directly test whether any freezing condition is in effect. Make the following changes in preparation. * Rename cgroup_freezing_or_frozen() to cgroup_freezing() and make it return bool. * Make cgroup_freezing() access task_freezer() under rcu read lock instead of task_lock(). This makes the state dereferencing racy against task moving to another cgroup; however, it was already racy without this change as ->state dereference wasn't synchronized. This will be later dealt with using attach hooks. * freezer->state is now set before trying to push tasks into the target state. -v2: Oleg pointed out that freeze_change_state() was setting freeze->state incorrectly to CGROUP_FROZEN instead of CGROUP_FREEZING. Fixed. -v3: Matt pointed out that setting CGROUP_FROZEN used to always invoke try_to_freeze_cgroup() regardless of the current state. Patch updated such that the actual freeze/thaw operations are always performed on invocation. This shouldn't make any difference unless something is broken. Signed-off-by: Tejun Heo Acked-by: Paul Menage Cc: Li Zefan Cc: Oleg Nesterov --- Reading git-diff-tree failed