From patchwork Wed Sep 6 06:25:52 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Coly Li X-Patchwork-Id: 9939961 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 9FD87602CC for ; Wed, 6 Sep 2017 06:26:41 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 91E1A205A4 for ; Wed, 6 Sep 2017 06:26:41 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 86BF328AE4; Wed, 6 Sep 2017 06:26:41 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0F193205A4 for ; Wed, 6 Sep 2017 06:26:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751480AbdIFG0j (ORCPT ); Wed, 6 Sep 2017 02:26:39 -0400 Received: from mx2.suse.de ([195.135.220.15]:42246 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751163AbdIFG0i (ORCPT ); Wed, 6 Sep 2017 02:26:38 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id BABF0AD1A; Wed, 6 Sep 2017 06:26:36 +0000 (UTC) From: Coly Li To: linux-bcache@vger.kernel.org, linux-block@vger.kernel.org, axboe@kernel.dk Cc: bcache@lists.ewheeler.net, Tang Junhui , stable@vger.kernel.org Subject: [PATCH 02/12] bcache: fix sequential large write IO bypass Date: Wed, 6 Sep 2017 14:25:52 +0800 Message-Id: <20170906062602.50497-3-colyli@suse.de> X-Mailer: git-send-email 2.13.5 In-Reply-To: <20170906062602.50497-1-colyli@suse.de> References: <20170906062602.50497-1-colyli@suse.de> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Tang Junhui Sequential write IOs were tested with bs=1M by FIO in writeback cache mode, these IOs were expected to be bypassed, but actually they did not. We debug the code, and find in check_should_bypass(): if (!congested && mode == CACHE_MODE_WRITEBACK && op_is_write(bio_op(bio)) && (bio-＞bi_opf & REQ_SYNC)) goto rescale that means, If in writeback mode, a write IO with REQ_SYNC flag will not be bypassed though it is a sequential large IO, It's not a correct thing to do actually, so this patch remove these codes. Signed-off-by: tang.junhui Reviewed-by: Kent Overstreet Reviewed-by: Eric Wheeler Cc: stable@vger.kernel.org --- drivers/md/bcache/request.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c index 019b3df9f1c6..958072a11347 100644 --- a/drivers/md/bcache/request.c +++ b/drivers/md/bcache/request.c @@ -400,12 +400,6 @@ static bool check_should_bypass(struct cached_dev *dc, struct bio *bio) if (!congested && !dc->sequential_cutoff) goto rescale; - if (!congested && - mode == CACHE_MODE_WRITEBACK && - op_is_write(bio->bi_opf) && - op_is_sync(bio->bi_opf)) - goto rescale; - spin_lock(&dc->io_lock); hlist_for_each_entry(i, iohash(dc, bio->bi_iter.bi_sector), hash)