Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752853Ab1DRACN (ORCPT ); Sun, 17 Apr 2011 20:02:13 -0400 Received: from ipmail06.adl2.internode.on.net ([150.101.137.129]:41299 "EHLO ipmail06.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751570Ab1DRACI (ORCPT ); Sun, 17 Apr 2011 20:02:08 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AqgEABd8q015LHHJgWdsb2JhbAClWhUBARYmJcMSDoVjBJQ5 Date: Mon, 18 Apr 2011 10:02:04 +1000 From: Dave Chinner To: Raghavendra D Prabhu Cc: linux-mm@kvack.org, Artem Bityutskiy , Jens Axboe , Christoph Hellwig , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] Add check for dirty_writeback_interval in bdi_wakeup_thread_delayed Message-ID: <20110418000204.GQ21395@dastard> References: <20110417162308.GA1208@Xye> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110417162308.GA1208@Xye> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1547 Lines: 43 On Sun, Apr 17, 2011 at 09:53:08PM +0530, Raghavendra D Prabhu wrote: > In the function bdi_wakeup_thread_delayed, no checks are performed on > dirty_writeback_interval unlike other places and timeout is being set to > zero as result, thus defeating the purpose. So, I have changed it to be > passed default value of interval which is 500 centiseconds, when it is > set to zero. > I have also verified this and tested it. > > Signed-off-by: Raghavendra D Prabhu > --- > mm/backing-dev.c | 5 ++++- > 1 files changed, 4 insertions(+), 1 deletions(-) > > diff --git a/mm/backing-dev.c b/mm/backing-dev.c > index befc875..d06533c 100644 > --- a/mm/backing-dev.c > +++ b/mm/backing-dev.c > @@ -336,7 +336,10 @@ void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi) > { > unsigned long timeout; > - timeout = msecs_to_jiffies(dirty_writeback_interval * 10); > + if (dirty_writeback_interval) > + timeout = msecs_to_jiffies(dirty_writeback_interval * 10); > + else > + timeout = msecs_to_jiffies(5000); > mod_timer(&bdi->wb.wakeup_timer, jiffies + timeout); > } Isn't the problem that the sysctl handler does not have a min/max valid value set? I.e. to prevent invalid values from being set in the first place? Cheers, Dave. -- Dave Chinner david@fromorbit.com -- 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/