From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:49762 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752197AbdIVMD4 (ORCPT ); Fri, 22 Sep 2017 08:03:56 -0400 Subject: Patch "bcache: fix sequential large write IO bypass" has been added to the 4.13-stable tree To: tang.junhui@zte.com.cn, axboe@kernel.dk, bcache@linux.ewheeler.net, gregkh@linuxfoundation.org, kent.overstreet@gmail.com Cc: , From: Date: Fri, 22 Sep 2017 14:04:01 +0200 Message-ID: <150608184124344@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled bcache: fix sequential large write IO bypass to the 4.13-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: bcache-fix-sequential-large-write-io-bypass.patch and it can be found in the queue-4.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From c81ffa32a214c84b08900fbc9d432187bd948eba Mon Sep 17 00:00:00 2001 From: Tang Junhui Date: Wed, 6 Sep 2017 14:25:52 +0800 Subject: bcache: fix sequential large write IO bypass MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Tang Junhui commit c81ffa32a214c84b08900fbc9d432187bd948eba upstream. 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 Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/md/bcache/request.c | 6 ------ 1 file changed, 6 deletions(-) --- a/drivers/md/bcache/request.c +++ b/drivers/md/bcache/request.c @@ -400,12 +400,6 @@ static bool check_should_bypass(struct c 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) Patches currently in stable-queue which might be from tang.junhui@zte.com.cn are queue-4.13/bcache-do-not-subtract-sectors_to_gc-for-bypassed-io.patch queue-4.13/bcache-correct-cache_dirty_target-in-__update_writeback_rate.patch queue-4.13/bcache-fix-for-gc-and-write-back-race.patch queue-4.13/bcache-initialize-dirty-stripes-in-flash_dev_run.patch queue-4.13/bcache-fix-sequential-large-write-io-bypass.patch