Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758897AbZDBNzW (ORCPT ); Thu, 2 Apr 2009 09:55:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754760AbZDBNzF (ORCPT ); Thu, 2 Apr 2009 09:55:05 -0400 Received: from mx2.redhat.com ([66.187.237.31]:48274 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756780AbZDBNzD (ORCPT ); Thu, 2 Apr 2009 09:55:03 -0400 Date: Thu, 2 Apr 2009 09:52:02 -0400 From: Vivek Goyal To: Divyesh Shah Cc: nauman@google.com, lizf@cn.fujitsu.com, mikew@google.com, fchecconi@gmail.com, paolo.valente@unimore.it, jens.axboe@oracle.com, ryov@valinux.co.jp, fernando@intellilink.co.jp, s-uchida@ap.jp.nec.com, taka@valinux.co.jp, guijianfeng@cn.fujitsu.com, arozansk@redhat.com, jmoyer@redhat.com, oz-kernel@redhat.com, dhaval@linux.vnet.ibm.com, balbir@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, akpm@linux-foundation.org, menage@google.com, peterz@infradead.org Subject: Re: [PATCH 02/10] Common flat fair queuing code in elevaotor layer Message-ID: <20090402135202.GB12851@redhat.com> References: <1236823015-4183-1-git-send-email-vgoyal@redhat.com> <1236823015-4183-3-git-send-email-vgoyal@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2309 Lines: 57 On Wed, Apr 01, 2009 at 09:06:40PM -0700, Divyesh Shah wrote: > On Wed, Mar 11, 2009 at 6:56 PM, Vivek Goyal wrote: > > +/* > > + * elv_exit_fq_data is called before we call elevator_exit_fn. Before > > + * we ask elevator to cleanup its queues, we do the cleanup here so > > + * that all the group and idle tree references to ioq are dropped. Later > > + * during elevator cleanup, ioc reference will be dropped which will lead > > + * to removal of ioscheduler queue as well as associated ioq object. > > + */ > > +void elv_exit_fq_data(struct elevator_queue *e) > > +{ > > + struct elv_fq_data *efqd = &e->efqd; > > + struct request_queue *q = efqd->queue; > > + > > + if (!elv_iosched_fair_queuing_enabled(e)) > > + return; > > + > > + elv_shutdown_timer_wq(e); > > + > > + spin_lock_irq(q->queue_lock); > > + /* This should drop all the idle tree references of ioq */ > > + elv_free_idle_ioq_list(e); > > + spin_unlock_irq(q->queue_lock); > > + > > + elv_shutdown_timer_wq(e); > > + > > + BUG_ON(timer_pending(&efqd->idle_slice_timer)); > > + io_free_root_group(e); > > +} > > > > Hi Vivek, > When cleaning up the elv_fq_data and ioqs for the iogs > associated with a device on elv_exit(), I don't see any iogs except > the root group being freed. In io_disconnect_groups() you remove the > ioqs from each of the iog and move them to the root iog and then > delete the root iog. Am I missing something here or are there leftover > iogs at elv_exit? Hi Divyesh, io_groups are linked in two lists. One list is maintained by io_cgroup to keep track of how many io_groups are there associated with this cgroup and other list is maintained in elv_fq_data to keep track of how many io_groups are actually doing IO to this device. Upon elevator exit, we remove the io_groups (io_disconnect_groups())from the list maintained by elv_fq_data but we don't free them up. Freeing up is finally done when cgroup is being deleted (iocg_destroy()). Thanks Vivek -- 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/