From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756229Ab1HCXkB (ORCPT ); Wed, 3 Aug 2011 19:40:01 -0400 Received: from cantor2.suse.de ([195.135.220.15]:33806 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756130Ab1HCX2i (ORCPT ); Wed, 3 Aug 2011 19:28:38 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Wed Aug 3 15:12:50 2011 Message-Id: <20110803221250.879500135@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Wed, 03 Aug 2011 15:01:28 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Peter Zijlstra , Wu Fengguang , Miklos Szeredi Subject: [068/102] mm/backing-dev.c: reset bdi min_ratio in bdi_unregister() In-Reply-To: <20110803221345.GA10346@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.0-stable review patch. If anyone has any objections, please let us know. ------------------ From: Peter Zijlstra commit ccb6108f5b0b541d3eb332c3a73e645c0f84278e upstream. Vito said: : The system has many usb disks coming and going day to day, with their : respective bdi's having min_ratio set to 1 when inserted. It works for : some time until eventually min_ratio can no longer be set, even when the : active set of bdi's seen in /sys/class/bdi/*/min_ratio doesn't add up to : anywhere near 100. : : This then leads to an unrelated starvation problem caused by write-heavy : fuse mounts being used atop the usb disks, a problem the min_ratio setting : at the underlying devices bdi effectively prevents. Fix this leakage by resetting the bdi min_ratio when unregistering the BDI. Signed-off-by: Peter Zijlstra Reported-by: Vito Caputo Cc: Wu Fengguang Cc: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/backing-dev.c | 1 + 1 file changed, 1 insertion(+) --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -606,6 +606,7 @@ static void bdi_prune_sb(struct backing_ void bdi_unregister(struct backing_dev_info *bdi) { if (bdi->dev) { + bdi_set_min_ratio(bdi, 0); trace_writeback_bdi_unregister(bdi); bdi_prune_sb(bdi); del_timer_sync(&bdi->wb.wakeup_timer);