Date: Wed, 25 Jun 2014 15:54:43 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: David Rientjes <rientjes@google.com>
Cc: Stefan Bader <stefan.bader@canonical.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        linux-kernel@vger.kernel.org, Eric Dumazet <eric.dumazet@gmail.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: fs/stat: Reduce memory requirements for stat_open
Message-Id: <20140625155443.9b0db555884e2fcc284f2842@linux-foundation.org>
In-Reply-To: <alpine.DEB.2.02.1406251551460.4592@chino.kir.corp.google.com>
References: <1402578017-16637-1-git-send-email-stefan.bader@canonical.com>
	<20140612134149.GC4296@osiris>
	<5399B301.9030108@canonical.com>
	<alpine.DEB.2.02.1406241642280.22030@chino.kir.corp.google.com>
	<53AA746A.3030303@canonical.com>
	<alpine.DEB.2.02.1406251551460.4592@chino.kir.corp.google.com>
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On Wed, 25 Jun 2014 15:52:30 -0700 (PDT) David Rientjes <rientjes@google.com> wrote:

> On Wed, 25 Jun 2014, Stefan Bader wrote:
> 
> > Heiko and I both had the same issue. Since some x86 hardware also reaches a lot
> > of CPUs (hyperthreads included), we bumped the possible number of CPUs to 256 at
> > least for the 64bit kernel. And that resulted in failed accesses to /proc/stat
> > when memory became fragmented.
> > So the first patch will avoid this on most systems. I have not seen this myself,
> > but I would expect him to be happy with 1/2 already. For really excessive
> > hardware 2/2 will close the gap.
> > Since this is no critical bug, I am fine with 3.17, too. I have not done so,
> > yet, but I could let our reporter try the patches (again, probably not verifying
> > the second part). Just waited to do so to see whether the code settles down to
> > these changes.
> > 
> 
> Ok, thanks.  Looks like
> 
> proc-stat-convert-to-single_open_size.patch
> fs-seq_file-fallback-to-vmalloc-allocation.patch
> 
> are destined for 3.17.

Actually I've bumped them into the 3.16 queue, cc stable.
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