From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vivek Goyal Subject: Re: [Lsf] IO less throttling and cgroup aware writeback Date: Thu, 7 Apr 2011 17:34:49 -0400 Message-ID: <20110407213449.GG27778@redhat.com> References: <20110401171838.GD20986@redhat.com> <20110401214947.GE6957@dastard> <20110405131359.GA14239@redhat.com> <20110405225639.GB31057@dastard> <20110406153954.GB18777@redhat.com> <20110406233602.GK31057@dastard> <20110407192424.GE27778@redhat.com> <20110407203303.GA13078@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Dave Chinner , James Bottomley , lsf@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org To: Christoph Hellwig Return-path: Received: from mx1.redhat.com ([209.132.183.28]:36540 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752199Ab1DGVfH (ORCPT ); Thu, 7 Apr 2011 17:35:07 -0400 Content-Disposition: inline In-Reply-To: <20110407203303.GA13078@infradead.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, Apr 07, 2011 at 04:33:03PM -0400, Christoph Hellwig wrote: > On Thu, Apr 07, 2011 at 03:24:24PM -0400, Vivek Goyal wrote: > > IIUC, so first we need to fix existing code where we seem to be moving > > any inode on bdi writeback list based on I_DIRTY flag. > > I_DIRTY is a set of flags. Inodes are on the dirty list if any of > the flags is set. > > > BTW, what's the difference between I_DIRTY_DATASYNC and I_DIRTY_PAGES? To > > me both seem to mean that data needs to be written back and not the > > inode itself. > > I_DIRTY_PAGES means dirty data (pages) > I_DIRTY_DATASYNC means dirty metadata which needs to be written for fdatasync > I_DIRTY_SYNC means dirty metadata which only needs to be written for fsync Ok, that helps. Thanks. So an fdatasync() can write back some metadata too if I_DIRTY_DATASYNC is set. Thanks Vivek