From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 73BC6900086 for ; Mon, 18 Apr 2011 03:09:01 -0400 (EDT) Date: Mon, 18 Apr 2011 12:38:40 +0530 From: Raghavendra D Prabhu Subject: Re: [TOME] Re: [PATCH 1/1] Add check for dirty_writeback_interval in bdi_wakeup_thread_delayed Message-ID: <20110418070840.GB5143@Xye> References: <20110417162308.GA1208@Xye> <20110418000204.GQ21395@dastard> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="zCKi3GIZzVBPywwA" Content-Disposition: inline In-Reply-To: <20110418000204.GQ21395@dastard> Sender: owner-linux-mm@kvack.org List-ID: To: Dave Chinner Cc: linux-mm@kvack.org, Artem Bityutskiy , Jens Axboe , Christoph Hellwig , Andrew Morton , linux-kernel@vger.kernel.org --zCKi3GIZzVBPywwA Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline * On Mon, Apr 18, 2011 at 10:02:04AM +1000, Dave Chinner wrote: >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. 0 is a valid value for dirty_writeback_interval which according to the definition/documentation is disabled when set to 0. In other places, a constraint check is done on that value except here. --zCKi3GIZzVBPywwA Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQEcBAEBAgAGBQJNq+N4AAoJEKYW3KHXK+l3APQIAJ/rUNH9Xj3aqEoQETElAV/D xb/Uj7klbjAlRXFPHh+1gn09NdUorsBLn+pxqwS1VAkq1Od/SWyN3ElNxS0baU17 joa8dhU4eLiTJmojowiFsx8nl8+CU4F4wuZHdkaGFRSMrEuLlxapSH2ehYdfNJnc oHgBD1lRFRuD4uwzsRqwngED4v0Oz0oUO8z4kP4Pjmix8rzgVYxKyioU/cJfFsf1 QSWZU/mqMrjs8mb7M5yUWF8jVrEuu+0LuEJ1F70vr6K8w/9eQvE9AnFlgRfZiqus kNkC42pVB/IoltrVvSmxzrxyNmliCzbGyWb1C+P1x40pSrGLkDRy4sMl0L+wS1I= =mPbO -----END PGP SIGNATURE----- --zCKi3GIZzVBPywwA-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org