On Wed, Nov 16, 2011 at 06:02:42PM +0100, Thomas Gleixner wrote: > On Wed, 16 Nov 2011, Steven Rostedt wrote: > > On Wed, 2011-11-16 at 17:16 +0800, Yong Zhang wrote: > > > Looking at commit 4799401f [memcg: Fix race condition in > > > memcg_check_events() with this_cpu usage], we just want > > > to disable migration. So use the right API in -rt. This > > > will cure below warning. > > No this won't work. Not even for -rt. If we disable migration but not > > preemption, then two tasks can take this path. And the checks in > > __memcg_event_check() will be corrupted because nothing is protecting > > the updates from two tasks going into the same path. > > > > Perhaps a local_lock would work. > > Yes, that's the only sensible option for now. Untested patch below. I run a quick test and it looks like the problem is gone. Cheers, -- Luis Henriques -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
