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 SMTP id 0827F6B0249 for ; Tue, 6 Jul 2010 18:28:19 -0400 (EDT) Received: by iwn2 with SMTP id 2so6381872iwn.14 for ; Tue, 06 Jul 2010 15:28:18 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20100706202758.GC18210@cmpxchg.org> References: <20100702125155.69c02f85.akpm@linux-foundation.org> <20100705134949.GC13780@csn.ul.ie> <20100706093529.CCD1.A69D9226@jp.fujitsu.com> <20100706101235.GE13780@csn.ul.ie> <20100706152539.GG13780@csn.ul.ie> <20100706202758.GC18210@cmpxchg.org> Date: Wed, 7 Jul 2010 07:28:14 +0900 Message-ID: Subject: Re: [PATCH 12/14] vmscan: Do not writeback pages in direct reclaim From: Minchan Kim Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org To: Johannes Weiner Cc: Mel Gorman , KOSAKI Motohiro , Andrew Morton , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Dave Chinner , Chris Mason , Nick Piggin , Rik van Riel , Christoph Hellwig , KAMEZAWA Hiroyuki , Andrea Arcangeli List-ID: On Wed, Jul 7, 2010 at 5:27 AM, Johannes Weiner wrote: > On Tue, Jul 06, 2010 at 04:25:39PM +0100, Mel Gorman wrote: >> On Tue, Jul 06, 2010 at 08:24:57PM +0900, Minchan Kim wrote: >> > but it is still problem in case of swap file. >> > That's because swapout on swapfile cause file system writepage which >> > makes kernel stack overflow. >> >> I don't *think* this is a problem unless I missed where writing out to >> swap enters teh filesystem code. I'll double check. > > It bypasses the fs. =C2=A0On swapon, the blocks are resolved > (mm/swapfile.c::setup_swap_extents) and then the writeout path uses > bios directly (mm/page_io.c::swap_writepage). > > (GFP_NOFS still includes __GFP_IO, so allows swapping) > > =C2=A0 =C2=A0 =C2=A0 =C2=A0Hannes Thanks, Hannes. You're right. Extents would be resolved by setup_swap_extents. Sorry for confusing, Mel. It was just my guessing about Kosaki's mention but he might say another sto= ry. Ignore me. --=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/ . Don't email: email@kvack.org