From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932086AbWGDIhr (ORCPT ); Tue, 4 Jul 2006 04:37:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932097AbWGDIhr (ORCPT ); Tue, 4 Jul 2006 04:37:47 -0400 Received: from mail.clusterfs.com ([206.168.112.78]:34529 "EHLO mail.clusterfs.com") by vger.kernel.org with ESMTP id S932086AbWGDIhr (ORCPT ); Tue, 4 Jul 2006 04:37:47 -0400 From: Nikita Danilov MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <17578.10167.898525.424656@gargle.gargle.HOWL> Date: Tue, 4 Jul 2006 12:32:55 +0400 To: "Ananiev, Leonid I" Cc: Linux Kernel Mailing List Subject: Re: [PATCH] mm: moving dirty pages balancing to pdfludh entirely Newsgroups: gmane.linux.kernel In-Reply-To: References: X-Mailer: VM 7.17 under 21.5 (patch 17) "chayote" (+CVS-20040321) XEmacs Lucid Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org [Please, don't trim CC/To fields: LKML is too high traffic to read in its entirety.] Ananiev, Leonid I writes: > Nikita Danilov writes: > > Wouldn't this interfere with current->backing_dev_info logic? > > The proposed patch does not modify that logic. Indeed, it *interferes* with it: in the original code, process doing direct reclaim during balance_dirty_pages() generic_file_write()->balance_dirty_pages()->...->__alloc_pages()->...->pageout() performs page-out even if queue is congested. Intent of this is to throttle writers, and reduce risk of running oom (certain file systems, especially ones with delayed allocation, tend to allocate a lot of memory in balance_dirty_pages()->writepages() paths). Your patch breaks this mechanism. Nikita.