From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:35642 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751968AbdFLJGn (ORCPT ); Mon, 12 Jun 2017 05:06:43 -0400 Subject: Patch "cfq-iosched: fix the delay of cfq_group's vdisktime under iops mode" has been added to the 4.9-stable tree To: houtao1@huawei.com, axboe@fb.com, gregkh@linuxfoundation.org, jack@suse.cz Cc: , From: Date: Mon, 12 Jun 2017 11:06:37 +0200 Message-ID: <149725839734242@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 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 cfq-iosched: fix the delay of cfq_group's vdisktime under iops mode to the 4.9-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: cfq-iosched-fix-the-delay-of-cfq_group-s-vdisktime-under-iops-mode.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 5be6b75610cefd1e21b98a218211922c2feb6e08 Mon Sep 17 00:00:00 2001 From: Hou Tao Date: Wed, 1 Mar 2017 09:02:33 +0800 Subject: cfq-iosched: fix the delay of cfq_group's vdisktime under iops mode From: Hou Tao commit 5be6b75610cefd1e21b98a218211922c2feb6e08 upstream. When adding a cfq_group into the cfq service tree, we use CFQ_IDLE_DELAY as the delay of cfq_group's vdisktime if there have been other cfq_groups already. When cfq is under iops mode, commit 9a7f38c42c2b ("cfq-iosched: Convert from jiffies to nanoseconds") could result in a large iops delay and lead to an abnormal io schedule delay for the added cfq_group. To fix it, we just need to revert to the old CFQ_IDLE_DELAY value: HZ / 5 when iops mode is enabled. Despite having the same value, the delay of a cfq_queue in idle class and the delay of cfq_group are different things, so I define two new macros for the delay of a cfq_group under time-slice mode and iops mode. Fixes: 9a7f38c42c2b ("cfq-iosched: Convert from jiffies to nanoseconds") Signed-off-by: Hou Tao Acked-by: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/cfq-iosched.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -36,9 +36,13 @@ static const u64 cfq_target_latency = (u static const int cfq_hist_divisor = 4; /* - * offset from end of service tree + * offset from end of queue service tree for idle class */ #define CFQ_IDLE_DELAY (NSEC_PER_SEC / 5) +/* offset from end of group service tree under time slice mode */ +#define CFQ_SLICE_MODE_GROUP_DELAY (NSEC_PER_SEC / 5) +/* offset from end of group service under IOPS mode */ +#define CFQ_IOPS_MODE_GROUP_DELAY (HZ / 5) /* * below this threshold, we consider thinktime immediate @@ -1370,6 +1374,14 @@ cfq_group_service_tree_add(struct cfq_rb cfqg->vfraction = max_t(unsigned, vfr, 1); } +static inline u64 cfq_get_cfqg_vdisktime_delay(struct cfq_data *cfqd) +{ + if (!iops_mode(cfqd)) + return CFQ_SLICE_MODE_GROUP_DELAY; + else + return CFQ_IOPS_MODE_GROUP_DELAY; +} + static void cfq_group_notify_queue_add(struct cfq_data *cfqd, struct cfq_group *cfqg) { @@ -1389,7 +1401,8 @@ cfq_group_notify_queue_add(struct cfq_da n = rb_last(&st->rb); if (n) { __cfqg = rb_entry_cfqg(n); - cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY; + cfqg->vdisktime = __cfqg->vdisktime + + cfq_get_cfqg_vdisktime_delay(cfqd); } else cfqg->vdisktime = st->min_vdisktime; cfq_group_service_tree_add(st, cfqg); Patches currently in stable-queue which might be from houtao1@huawei.com are queue-4.9/cfq-iosched-fix-the-delay-of-cfq_group-s-vdisktime-under-iops-mode.patch