From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f171.google.com (mail-ig0-f171.google.com [209.85.213.171]) by kanga.kvack.org (Postfix) with ESMTP id E3F176B0038 for ; Fri, 13 Feb 2015 04:56:07 -0500 (EST) Received: by mail-ig0-f171.google.com with SMTP id h15so9530589igd.4 for ; Fri, 13 Feb 2015 01:56:07 -0800 (PST) Received: from nm39-vm5.bullet.mail.ne1.yahoo.com (nm39-vm5.bullet.mail.ne1.yahoo.com. [98.138.229.165]) by mx.google.com with ESMTPS id o66si5055906ioe.84.2015.02.13.01.56.07 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 13 Feb 2015 01:56:07 -0800 (PST) Date: Fri, 13 Feb 2015 09:52:16 +0000 (UTC) From: Cheng Rk Reply-To: Cheng Rk Message-ID: <131740628.109294.1423821136530.JavaMail.yahoo@mail.yahoo.com> In-Reply-To: References: Subject: Re: How to controll Buffers to be dilligently reclaimed? MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Konstantin Khlebnikov Cc: "linux-mm@kvack.org" On Thursday, February 12, 2015 11:34 PM, Konstantin Khlebnikov wrote: >> >> -bash-4.2$ sudo losetup -a >> /dev/loop0: [0005]:16512 (/dev/dm-2) >> -bash-4.2$ free -m >> total used free shared buffers cached >> Mem: 48094 46081 2012 40 40324 2085 >> -/+ buffers/cache: 3671 44422 >> Swap: 8191 5 8186 >> >> >> I've tried sysctl mm.vfs_cache_pressure=10000 but that seems working to Cached >> memory, I wonder is there another sysctl for reclaming Buffers? > AFAIK "Buffers" is just a page-cache of block devices. > From reclaimer's point of view they have no difference from file page-cache. > Could you post oom-killer log, there should be a lot of numbers > describing memory state. in this case, 40GB memory got stuck in Buffers, and 90+% of them are reclaimable (can be verified by vm.drop_caches manual reclaim) if Buffers are treated same as Cached, why mm.vfs_cache_pressure=10000 (or even I tried up to 1,000,000) can't get Buffers reclaimed early? I have some oom-killer msgs but were with older kernels, after set vm.overcommit_memory=2, it simply returns -ENOMEM, unable to spawn any new container, why doesn't it even try to reclaim some memory from those 40GB Buffers, Thanks, -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org