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From: Tejun Heo <tj@kernel.org>
To: axboe@kernel.dk
Cc: linux-block@vger.kernel.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-team@fb.com, newella@fb.com,
	Tejun Heo <tj@kernel.org>
Subject: [PATCH 07/27] blk-iocost: make iocg_kick_waitq() call iocg_kick_delay() after paying debt
Date: Tue,  1 Sep 2020 14:52:37 -0400	[thread overview]
Message-ID: <20200901185257.645114-8-tj@kernel.org> (raw)
In-Reply-To: <20200901185257.645114-1-tj@kernel.org>

iocg_kick_waitq() is the function which pays debt and iocg_kick_delay()
updates the actual delay status accordingly. If iocg_kick_delay() is not
called after iocg_kick_delay() updated debt, unnecessarily large delays can
be applied temporarily.

Let's make sure such conditions don't occur by making iocg_kick_waitq()
always call iocg_kick_delay() after paying debt.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
 block/blk-iocost.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index ac22d761a350..b2b8dfbeee5a 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -1226,6 +1226,8 @@ static void iocg_kick_waitq(struct ioc_gq *iocg, struct ioc_now *now)
 		atomic64_add(delta, &iocg->vtime);
 		atomic64_add(delta, &iocg->done_vtime);
 		iocg->abs_vdebt -= abs_delta;
+
+		iocg_kick_delay(iocg, now);
 	}
 
 	/*
@@ -1383,7 +1385,6 @@ static void ioc_timer_fn(struct timer_list *timer)
 		if (waitqueue_active(&iocg->waitq) || iocg->abs_vdebt) {
 			/* might be oversleeping vtime / hweight changes, kick */
 			iocg_kick_waitq(iocg, &now);
-			iocg_kick_delay(iocg, &now);
 		} else if (iocg_is_idle(iocg)) {
 			/* no waiter and idle, deactivate */
 			iocg->last_inuse = iocg->inuse;
-- 
2.26.2


  parent reply	other threads:[~2020-09-01 18:56 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-01 18:52 [PATCHSET for-5.10/block] blk-iocost: iocost: improve donation, debt and excess handling Tejun Heo
2020-09-01 18:52 ` [PATCH 01/27] blk-iocost: ioc_pd_free() shouldn't assume irq disabled Tejun Heo
2020-09-01 18:52 ` [PATCH 02/27] blk-stat: make q->stats->lock irqsafe Tejun Heo
2020-09-01 18:52   ` Tejun Heo
2020-09-01 18:52 ` [PATCH 03/27] blk-iocost: use local[64]_t for percpu stat Tejun Heo
2020-09-01 18:52   ` Tejun Heo
2020-11-20 21:51   ` Stafford Horne
2020-11-20 22:13     ` Tejun Heo
2020-11-20 22:13       ` Tejun Heo
2020-09-01 18:52 ` [PATCH 04/27] blk-iocost: rename propagate_active_weights() to propagate_weights() Tejun Heo
2020-09-01 18:52 ` [PATCH 05/27] blk-iocost: clamp inuse and skip noops in __propagate_weights() Tejun Heo
2020-09-01 18:52 ` [PATCH 06/27] blk-iocost: move iocg_kick_delay() above iocg_kick_waitq() Tejun Heo
2020-09-01 18:52 ` Tejun Heo [this message]
2020-09-01 18:52 ` [PATCH 08/27] blk-iocost: s/HWEIGHT_WHOLE/WEIGHT_ONE/g Tejun Heo
2020-09-01 18:52   ` Tejun Heo
2020-09-01 18:52 ` [PATCH 09/27] blk-iocost: use WEIGHT_ONE based fixed point number for weights Tejun Heo
2020-09-01 18:52 ` [PATCH 10/27] blk-iocost: make ioc_now->now and ioc->period_at 64bit Tejun Heo
2020-09-01 18:52 ` [PATCH 11/27] blk-iocost: streamline vtime margin and timer slack handling Tejun Heo
2020-09-01 18:52 ` [PATCH 12/27] blk-iocost: grab ioc->lock for debt handling Tejun Heo
2020-09-01 18:52 ` [PATCH 13/27] blk-iocost: add absolute usage stat Tejun Heo
2020-09-01 18:52   ` Tejun Heo
2020-09-01 18:52 ` [PATCH 14/27] blk-iocost: calculate iocg->usages[] from iocg->local_stat.usage_us Tejun Heo
2020-09-01 18:52   ` Tejun Heo
2020-09-01 18:52 ` [PATCH 15/27] blk-iocost: replace iocg->has_surplus with ->surplus_list Tejun Heo
2020-09-01 18:52 ` [PATCH 16/27] blk-iocost: decouple vrate adjustment from surplus transfers Tejun Heo
2020-09-01 18:52   ` Tejun Heo
2020-09-01 18:52 ` [PATCH 17/27] blk-iocost: restructure surplus donation logic Tejun Heo
2020-09-01 18:52 ` [PATCH 18/27] blk-iocost: implement Andy's method for donation weight updates Tejun Heo
2020-09-01 18:52 ` [PATCH 19/27] blk-iocost: revamp donation amount determination Tejun Heo
2020-09-01 18:52 ` [PATCH 20/27] blk-iocost: revamp in-period donation snapbacks Tejun Heo
2020-09-01 18:52   ` Tejun Heo
2020-09-01 18:52 ` [PATCH 21/27] blk-iocost: revamp debt handling Tejun Heo
2020-09-01 18:52   ` Tejun Heo
2020-09-01 18:52 ` [PATCH 22/27] blk-iocost: implement delay adjustment hysteresis Tejun Heo
2020-09-01 18:52 ` [PATCH 23/27] blk-iocost: halve debts if device stays idle Tejun Heo
2020-09-01 18:52 ` [PATCH 24/27] blk-iocost: implement vtime loss compensation Tejun Heo
2020-09-01 18:52 ` [PATCH 25/27] blk-iocost: restore inuse update tracepoints Tejun Heo
2020-09-01 18:52 ` [PATCH 26/27] blk-iocost: add three debug stat - cost.wait, indebt and indelay Tejun Heo
2020-09-01 18:52   ` Tejun Heo
2020-09-01 18:52 ` [PATCH 27/27] blk-iocost: update iocost_monitor.py Tejun Heo
2020-09-01 22:57 ` [PATCHSET for-5.10/block] blk-iocost: iocost: improve donation, debt and excess handling Jens Axboe
2020-09-01 22:57   ` Jens Axboe

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