From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o536oQOE140151 for ; Thu, 3 Jun 2010 01:50:28 -0500 Received: from bombadil.infradead.org (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id BB9CE391DD7 for ; Wed, 2 Jun 2010 23:52:54 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org [18.85.46.34]) by cuda.sgi.com with ESMTP id BZ1KeKLHdLOrmcCe for ; Wed, 02 Jun 2010 23:52:54 -0700 (PDT) Date: Thu, 3 Jun 2010 02:52:52 -0400 From: Christoph Hellwig Subject: Re: [PATCH 02/17] xfs: skip writeback from reclaim context Message-ID: <20100603065252.GA28592@infradead.org> References: <20100531160727.842750532@bombadil.infradead.org> <20100531160859.184576507@bombadil.infradead.org> <20100602043957.GB7011@dastard> <20100602100812.GA25035@infradead.org> <20100602230209.GA27325@dastard> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20100602230209.GA27325@dastard> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Dave Chinner Cc: linux-mm@kvack.org, xfs@oss.sgi.com On Thu, Jun 03, 2010 at 09:02:09AM +1000, Dave Chinner wrote: > Did you skip it unconditionally, or only when a transaction was > required? xfs_vm_releasepage is mostly a no-op if no transaction is required. If we have neither delalloc nor unwritten buffer we do not actually enter xfs_page_state_convert, and ->releasepage also doesn't touch unampped buffers at all. > The scary part is that I've seen stack traces (i.e. most stack used) > through this reclaim path for delalloc conversion even for > allocations that are GFP_NOFS and the only thing saving us from > deadlocks is th PF_FSTRANS check. Even worse is that > shrinker_page_list() will call try_to_release_pages() without > checking whether it's allowed to enter the filesystem or not, so we > can be doing block allocation in places we've specifically told the > memory allocation subsystem not to.... s/shrinker_page_list/shrink_page_list/ and s/try_to_release_pages/try_to_release_page/ above. shrink_page_list takes the gfp_mask for try_to_release_page from the scan_control structure passed to it from all the top of the long callchain. I can't find anobvious bug, but this could cause a lot more harm. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs