Re: [PATCH] memcg: Fix race condition in memcg_check_events() withthis_cpu usage

[Steven Rostedt]

On Fri, 2011-09-23 at 19:39 -0700, Greg Thelen wrote:
> cc: updated Balbir Singh email address
> 
> On Fri, Sep 23, 2011 at 7:34 PM, Greg Thelen <gthelen@xxxxxxxxxx> wrote:
> > On Fri, Sep 23, 2011 at 5:54 PM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> >> From: Steven Rostedt <srostedt@xxxxxxxxxx>
> >>
> >> The code in memcg_check_events() calls this_cpu_read() on
> >> different variables without disabling preemption, and can cause
> >> the calculations to be done from two different CPU variables.
> >>
> >> Disable preemption throughout the check to keep apples and oranges
> >> from becoming a mixed drink.
> >>
> >> [ Added this_cpu to __this_cpu conversion by Johannes ]
> >>
> >> Cc: Greg Thelen <gthelen@xxxxxxxxxx>
> >> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> >> Cc: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
> 
> Correction:
> Cc: Balbir Singh <bsingharora@xxxxxxxxx>

Thanks, I was starting to hate that "return mail to sender" thing.

-- Steve

> 
> >> Cc: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
> >> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> >> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> >> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> >> Cc: Christoph Lameter <cl@xxxxxxxxx>
> >> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> >> Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
> >> Link: http://lkml.kernel.org/r/20110919212641.015320989@xxxxxxxxxxx
> >
> > Looks good to me.  Thanks.
> >
> > Reviewed-by: Greg Thelen <gthelen@xxxxxxxxxx>
> >


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