From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758540Ab1FAAfi (ORCPT ); Tue, 31 May 2011 20:35:38 -0400 Received: from shells.gnugeneration.com ([66.240.222.126]:56470 "HELO shells.gnugeneration.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1758489Ab1FAAfh (ORCPT ); Tue, 31 May 2011 20:35:37 -0400 X-Greylist: delayed 401 seconds by postgrey-1.27 at vger.kernel.org; Tue, 31 May 2011 20:35:37 EDT Date: Tue, 31 May 2011 19:28:54 -0500 From: lkml@pengaru.com To: linux-kernel@vger.kernel.org Subject: bdi_min_ratio never shrinks, ultimately preventing valid setting of min_ratio Message-ID: <20110601002854.GV5753@shells.gnugeneration.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org mm/page-writeback.c There is a static global bdi_min_ratio used for policing the setting of per-bdi min_ratio's, to ensure the sum doesn't cross 100. There is no place in this listing where the value is decremented by the respective bdi's min_ratio when a bdi is torn down. This looks like a bug to me, and I have a situation where I'm unable to set a min_ratio to 1 where the sum of /sys/class/bdi/*/min_ratio does not add up to 100, which is what triggered this investigation. Regards, Vito Caputo