Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755712AbZF1O53 (ORCPT ); Sun, 28 Jun 2009 10:57:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751785AbZF1O5V (ORCPT ); Sun, 28 Jun 2009 10:57:21 -0400 Received: from mail-gx0-f226.google.com ([209.85.217.226]:46240 "EHLO mail-gx0-f226.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751216AbZF1O5U convert rfc822-to-8bit (ORCPT ); Sun, 28 Jun 2009 10:57:20 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=X6RcJuA8W5yV4oKxiiAfrUcU81Z63ugvwe12nbK6rBNefc6copr6k5ZP1Jnr3p/6eG JK8VWwvwkUX2lp8IgQkbEBZ4VCM4Y6T2Z3sZeDmN647A0DkvMc1bI/L6IYQZ9S3MLUe+ lUUS7JkTXAx/SafFFl+c/v102hQab2JzdZrsU= MIME-Version: 1.0 In-Reply-To: <28c262360906280630n557bb182n5079e33d21ea4a83@mail.gmail.com> References: <3901.1245848839@redhat.com> <32411.1245336412@redhat.com> <20090517022327.280096109@intel.com> <2015.1245341938@redhat.com> <20090618095729.d2f27896.akpm@linux-foundation.org> <7561.1245768237@redhat.com> <26537.1246086769@redhat.com> <20090627125412.GA1667@cmpxchg.org> <20090628113246.GA18409@localhost> <28c262360906280630n557bb182n5079e33d21ea4a83@mail.gmail.com> Date: Sun, 28 Jun 2009 23:49:52 +0900 X-Google-Sender-Auth: 2d0c330c1e219396 Message-ID: <2f11576a0906280749v25ab725dn8f98fbc1d2e5a5fd@mail.gmail.com> Subject: Re: Found the commit that causes the OOMs From: KOSAKI Motohiro To: Minchan Kim Cc: Wu Fengguang , Johannes Weiner , David Howells , "riel@redhat.com" , Andrew Morton , LKML , Christoph Lameter , "peterz@infradead.org" , "tytso@mit.edu" , "linux-mm@kvack.org" , "elladan@eskimo.com" , "npiggin@suse.de" , "Barnes, Jesse" Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1600 Lines: 39 >> In David's OOM case, there are two symptoms: >> 1) 70000 unaccounted/leaked pages as found by Andrew >> ? (plus rather big number of PG_buddy and pagetable pages) >> 2) almost zero active_file/inactive_file; small inactive_anon; >> ? many slab and active_anon pages. >> >> In the situation of (2), the slab cache is _under_ scanned. So David >> got OOM when vmscan should have squeezed some free pages from the slab >> cache. Which is one important side effect of MinChan's patch? > > My patch's side effect is (2). > > My guessing is following as. > > 1. The number of page scanned in shrink_slab is increased in shrink_page_list. > And it is doubled for mapped page or swapcache. > 2. shrink_page_list is called by shrink_inactive_list > 3. shrink_inactive_list is called by shrink_list > > Look at the shrink_list. > If inactive lru list is low, it always call shrink_active_list not > shrink_inactive_list in case of anon. > It means it doesn't increased sc->nr_scanned. > Then shrink_slab can't shrink enough slab pages. > So, David OOM have a lot of slab pages and active anon pages. > > Does it make sense ? > If it make sense, we have to change shrink_slab's pressure method. > What do you think ? I'm confused. if system have no swap, get_scan_ratio() always return anon=0%. Then, the numver of inactive_anon is not effect to sc.nr_scanned. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/