From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx187.postini.com [74.125.245.187]) by kanga.kvack.org (Postfix) with SMTP id D78E86B0070 for ; Thu, 22 Nov 2012 20:58:50 -0500 (EST) Received: by mail-ia0-f169.google.com with SMTP id r4so7618039iaj.14 for ; Thu, 22 Nov 2012 17:58:50 -0800 (PST) Message-ID: <50AED854.7080300@gmail.com> Date: Fri, 23 Nov 2012 09:58:44 +0800 From: Jaegeuk Hanse MIME-Version: 1.0 Subject: Re: Problem in Page Cache Replacement References: <1353433362.85184.YahooMailNeo@web141101.mail.bf1.yahoo.com> <20121120182500.GH1408@quack.suse.cz> In-Reply-To: <20121120182500.GH1408@quack.suse.cz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: metin d Cc: Jan Kara , "linux-kernel@vger.kernel.org" , linux-mm@kvack.org On 11/21/2012 02:25 AM, Jan Kara wrote: > On Tue 20-11-12 09:42:42, metin d wrote: >> I have two PostgreSQL databases named data-1 and data-2 that sit on the >> same machine. Both databases keep 40 GB of data, and the total memory >> available on the machine is 68GB. >> >> I started data-1 and data-2, and ran several queries to go over all their >> data. Then, I shut down data-1 and kept issuing queries against data-2. >> For some reason, the OS still holds on to large parts of data-1's pages >> in its page cache, and reserves about 35 GB of RAM to data-2's files. As >> a result, my queries on data-2 keep hitting disk. >> >> I'm checking page cache usage with fincore. When I run a table scan query >> against data-2, I see that data-2's pages get evicted and put back into >> the cache in a round-robin manner. Nothing happens to data-1's pages, >> although they haven't been touched for days. Hi metin d, fincore is a tool or ...? How could I get it? Regards, Jaegeuk >> >> Does anybody know why data-1's pages aren't evicted from the page cache? >> I'm open to all kind of suggestions you think it might relate to problem. > Curious. Added linux-mm list to CC to catch more attention. If you run > echo 1 >/proc/sys/vm/drop_caches > does it evict data-1 pages from memory? > >> This is an EC2 m2.4xlarge instance on Amazon with 68 GB of RAM and no >> swap space. The kernel version is: >> >> $ uname -r >> 3.2.28-45.62.amzn1.x86_64 >> Edit: >> >> and it seems that I use one NUMA instance, if you think that it can a problem. >> >> $ numactl --hardware >> available: 1 nodes (0) >> node 0 cpus: 0 1 2 3 4 5 6 7 >> node 0 size: 70007 MB >> node 0 free: 360 MB >> node distances: >> node 0 >> 0: 10 > Honza -- 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