From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH 1/1]: Thaws refrigerated bdi flusher threads before invoking kthread_stop on them Date: Wed, 11 Nov 2009 12:59:04 +0100 Message-ID: <200911111259.04481.rjw@sisk.pl> References: <1257928216.15415.57.camel@boson> <200911111230.58479.rjw@sisk.pl> <1257940231.28810.2.camel@boson> Mime-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from ogre.sisk.pl ([217.79.144.158]:35243 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751563AbZKKL5q (ORCPT ); Wed, 11 Nov 2009 06:57:46 -0500 In-Reply-To: <1257940231.28810.2.camel@boson> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: romit@ti.com, "jens.axboe@oracle.com" Cc: Pavel Machek , "linux-kernel@vger.kernel.org" , "linux-omap@vger.kernel.org" , "linux-pm@lists.linux-foundation.org" On Wednesday 11 November 2009, Romit Dasgupta wrote: > Hello Rafael, > As suggested I have added the relevant information in the > changelog. The patch is below: > > For completness, below is the information from the Romit's introductory message > > (Romit, I really think that should go into the chagelog): > > Kicks out frozen bdi flusher task out of the refrigerator when the said task > needs to exit. > Steps to reproduce this. > 1) Mount a file system from MMC/SD card. > 2) Unmount the file system. This creates a flusher task. > 3) Attempt suspend to RAM. System is unresponsive. > > This is because the bdi flusher thread is already in the refrigerator and will > remain so until it is thawed. The MMC driver suspend routine ultimately will > issue a 'kthread_stop' on the bdi flusher thread and will block until the > flusher thread is exited. Since the bdi flusher thread is in the refrigerator > it never cleans up until thawed. > > Signed-off-by: Romit Dasgupta Thanks! I'd still like to know that this change is fine with Jens, though. Rafael > --- > diff --git a/mm/backing-dev.c b/mm/backing-dev.c > index 5a37e20..c757b05 100644 > --- a/mm/backing-dev.c > +++ b/mm/backing-dev.c > @@ -606,8 +606,11 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi) > * Finally, kill the kernel threads. We don't need to be RCU > * safe anymore, since the bdi is gone from visibility. > */ > - list_for_each_entry(wb, &bdi->wb_list, list) > + list_for_each_entry(wb, &bdi->wb_list, list) { > + if (unlikely(frozen(wb->task))) > + wb->task->flags &= ~PF_FROZEN; > kthread_stop(wb->task); > + } > } > > void bdi_unregister(struct backing_dev_info *bdi)