From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Subject: Re: [PATCH] cpusets: Allocate heap only when required
Date: Fri, 24 Jan 2014 05:36:31 -0500
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To: David Rientjes <rientjes-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>, Viresh Kumar <viresh.kumar-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, linaro-kernel-cunTk1MwBs8s++Sfvej+rw@public.gmane.org, patches-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Cgroups <cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>

On Fri, Jan 24, 2014 at 02:33:27AM -0800, David Rientjes wrote:
> It's not harmless, if heap_init() fails with -ENOMEM then the write fails 
> even though it may not be for memory_spread_page or memory_spread_slab, 
> which is the minority of the callers of this function.

And depending on details like that would actually be more harmful.
Please remember that all writes through cgroupfs may fail under very
high memory pressure.  There's no "this specific set of writes to this
specific knob isn't affected by memory pressure" guarantee.

Thanks.

-- 
tejun