Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755764Ab0FOBqc (ORCPT ); Mon, 14 Jun 2010 21:46:32 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:50742 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751882Ab0FOBqa (ORCPT ); Mon, 14 Jun 2010 21:46:30 -0400 Date: Mon, 14 Jun 2010 18:45:44 -0700 From: Andrew Morton To: Rik van Riel Cc: Dave Chinner , Mel Gorman , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Chris Mason , Nick Piggin , Johannes Weiner , Christoph Hellwig , KAMEZAWA Hiroyuki Subject: Re: [PATCH 11/12] vmscan: Write out dirty pages in batch Message-Id: <20100614184544.32b1c371.akpm@linux-foundation.org> In-Reply-To: <4C16D46D.3020302@redhat.com> References: <1276514273-27693-1-git-send-email-mel@csn.ul.ie> <1276514273-27693-12-git-send-email-mel@csn.ul.ie> <20100614231144.GG6590@dastard> <20100614162143.04783749.akpm@linux-foundation.org> <20100615003943.GK6590@dastard> <4C16D46D.3020302@redhat.com> X-Mailer: Sylpheed 2.7.1 (GTK+ 2.18.9; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1120 Lines: 24 On Mon, 14 Jun 2010 21:16:29 -0400 Rik van Riel wrote: > Would it be hard to add a "please flush this file" > way to call the filesystem flushing threads? Passing the igrab()bed inode into the flusher threads would fix the iput_final() problems, as long as the alloc_pages() caller never blocks indefinitely waiting for the work which the flusher threads are doing. Otherwise we get (very hard-to-hit) deadlocks where the alloc_pages() caller holds VFS locks and is waiting for the flusher threads while all the flusher threads are stuck under iput_final() waiting for those VFS locks. That's fixable by not using igrab()/iput(). You can use lock_page() to pin the address_space. Pass the address of the locked page across to the flusher threads so they don't try to lock it a second time, or just use trylocking on that writeback path or whatever. -- 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/