Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755726Ab3CYHbw (ORCPT ); Mon, 25 Mar 2013 03:31:52 -0400 Received: from moltke.seatribe.se ([178.63.100.209]:55546 "EHLO moltke.seatribe.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755394Ab3CYHbv (ORCPT ); Mon, 25 Mar 2013 03:31:51 -0400 Date: Mon, 25 Mar 2013 08:31:43 +0100 (CET) From: Fredrik Tolf To: Bart Van Assche cc: linux-kernel@vger.kernel.org Subject: Re: I/O blocked while dirty pages are being flushed In-Reply-To: <514ED516.4020009@acm.org> Message-ID: References: <514ED516.4020009@acm.org> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1450 Lines: 31 On Sun, 24 Mar 2013, Bart Van Assche wrote: > On 03/24/13 06:12, Fredrik Tolf wrote: >> While this flush is running, I find that many a process goes into disk >> sleep waiting for the flush to complete. This includes the process >> manipulating the mmapped file whenever it tries to redirty a page >> currently waiting to be flushed, but also, for instance, programs that >> write() to log files (since, I guess, the buffer page backing the last >> written portion of the log file is being flushed). > > Had you already encountered this article: Jonathan Corbet, The trouble with > stable pages, March 13, 2012 (http://lwn.net/Articles/486311/) ? I had not, but that certainly does seem to be the exact problem I'm having. Thanks for the link; it was a very interesting read! Does anyone know if any progress has been made since about any resolution of the situation? I notice linked mail threads with people saying that they have simply removed the calls to wait_on_page_writeback to resolve their problems. Can this still be considered safe, or have other systems than this block-device checksumming started depending on stable pages since? Like software RAID, for instance? -- Fredrik Tolf -- 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/