From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753011Ab0J0R3q (ORCPT ); Wed, 27 Oct 2010 13:29:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45590 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752416Ab0J0R3o (ORCPT ); Wed, 27 Oct 2010 13:29:44 -0400 Date: Wed, 27 Oct 2010 13:29:41 -0400 From: Vivek Goyal To: Jens Axboe , linux kernel mailing list Cc: yummylln@yahoo.com.cn Subject: [PATCH] blk-throttle: Fix calculation of max number of WRITES to be dispatched Message-ID: <20101027172941.GD12981@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org o Currently we try to dispatch more READS and less WRITES (75%, 25%) in one dispatch round. ummy pointed out that there is a bug in max_nr_writes calculation. This patch fixes it. Reported-by: ummy y Signed-off-by: Vivek Goyal --- block/blk-throttle.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linux-2.6/block/blk-throttle.c =================================================================== --- linux-2.6.orig/block/blk-throttle.c 2010-10-27 10:57:25.000000000 -0400 +++ linux-2.6/block/blk-throttle.c 2010-10-27 11:02:33.733048194 -0400 @@ -645,7 +645,7 @@ static int throtl_dispatch_tg(struct thr { unsigned int nr_reads = 0, nr_writes = 0; unsigned int max_nr_reads = throtl_grp_quantum*3/4; - unsigned int max_nr_writes = throtl_grp_quantum - nr_reads; + unsigned int max_nr_writes = throtl_grp_quantum - max_nr_reads; struct bio *bio; /* Try to dispatch 75% READS and 25% WRITES */