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Date: Wed, 24 Aug 2011 17:33:36 +0800
From: Wu Fengguang <fengguang.wu@intel.com>
Subject: Re: slow performance on disk/network i/o full speed after
 drop_caches
Message-ID: <20110824093336.GB5214@localhost>
References: <4E5494D4.1050605@profihost.ag>
 <CAOJsxLEFYW0eDbXQ0Uixf-FjsxHZ_1nmnovNx1CWj=m-c-_vJw@mail.gmail.com>
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To: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>
Cc: Pekka Enberg <penberg@kernel.org>, LKML <linux-kernel@vger.kernel.org>, "linux-mm@kvack.org" <linux-mm@kvack.org>, Andrew Morton <akpm@linux-foundation.org>, Mel Gorman <mel@csn.ul.ie>, Jens Axboe <jaxboe@fusionio.com>, Linux Netdev List <netdev@vger.kernel.org>

On Wed, Aug 24, 2011 at 05:01:03PM +0800, Stefan Priebe - Profihost AG wrote:
> 
> >> sync&&  echo 3>/proc/sys/vm/drop_caches&&  sleep 2&&  echo 0
> >>> /proc/sys/vm/drop_caches
> 
> Another way to get it working again is to stop some processes. Could be 
> mysql or apache or php fcgi doesn't matter. Just free some memory. 
> Although there are already 5GB free.

Is it a NUMA machine and _every_ node has enough free pages?

        grep . /sys/devices/system/node/node*/vmstat

Thanks,
Fengguang

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