From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 723736B0012 for ; Sat, 14 May 2011 21:38:03 -0400 (EDT) Received: by qwa26 with SMTP id 26so2607963qwa.14 for ; Sat, 14 May 2011 18:38:00 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110514174333.GW6008@one.firstfloor.org> References: <20110512054631.GI6008@one.firstfloor.org> <20110514165346.GV6008@one.firstfloor.org> <20110514174333.GW6008@one.firstfloor.org> Date: Sun, 15 May 2011 10:37:58 +0900 Message-ID: Subject: Re: Kernel falls apart under light memory pressure (i.e. linking vmlinux) From: Minchan Kim Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Andi Kleen Cc: linux-mm@kvack.org, Wu Fengguang On Sun, May 15, 2011 at 2:43 AM, Andi Kleen wrote: > Copying back linux-mm. > >> Recently, we added following patch. >> https://lkml.org/lkml/2011/4/26/129 >> If it's a culprit, the patch should solve the problem. > > It would be probably better to not do the allocations at all under > memory pressure. =C2=A0Even if the RA allocation doesn't go into reclaim Fair enough. I think we can do it easily now. If page_cache_alloc_readahead(ie, GFP_NORETRY) is fail, we can adjust RA window size or turn off a while. The point is that we can use the fail of __do_page_cache_readahead as sign of memory pressure. Wu, What do you think? > it may still "steal" allocations recently freed and needed by other > actors. This problem is general thing as well as RA. But it would be not a big problem in order-0 pages. If it's a really problem, it might sign we have to increase SWAP_CLUSTER_MA= X. The concern I thought is order-0 allocation happens with other higher-order reclaims in parallel. order-0 allocation can steal other's high order pages. For it, I sent a patch but I didn't have enough time to dig in. https://lkml.org/lkml/2011/5/2/93 I have a plan to do. > > -Andi > -- > ak@linux.intel.com -- Speaking for myself only. > --=20 Kind regards, Minchan Kim -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org