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 05/27] blk-iocost: clamp inuse and skip noops in __propagate_weights()
Date: Tue, 1 Sep 2020 14:52:35 -0400 [thread overview]
Message-ID: <20200901185257.645114-6-tj@kernel.org> (raw)
In-Reply-To: <20200901185257.645114-1-tj@kernel.org>
__propagate_weights() currently expects the callers to clamp inuse within
[1, active], which is needlessly fragile. The inuse adjustment logic is
going to be revamped, in preparation, let's make __propagate_weights() clamp
inuse on entry.
Also, make it avoid weight updates altogether if neither active or inuse is
changed.
Signed-off-by: Tejun Heo <tj@kernel.org>
---
block/blk-iocost.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 78e6919153d8..8dfe73dde2a8 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -897,7 +897,10 @@ static void __propagate_weights(struct ioc_gq *iocg, u32 active, u32 inuse)
lockdep_assert_held(&ioc->lock);
- inuse = min(active, inuse);
+ inuse = clamp_t(u32, inuse, 1, active);
+
+ if (active == iocg->active && inuse == iocg->inuse)
+ return;
for (lvl = iocg->level - 1; lvl >= 0; lvl--) {
struct ioc_gq *parent = iocg->ancestors[lvl];
--
2.26.2
next prev parent reply other threads:[~2020-09-01 18:53 UTC|newest]
Thread overview: 31+ 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 ` [PATCH 03/27] blk-iocost: use local[64]_t for percpu stat Tejun Heo
2020-11-20 21:51 ` Stafford Horne
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 ` Tejun Heo [this message]
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 ` [PATCH 07/27] blk-iocost: make iocg_kick_waitq() call iocg_kick_delay() after paying debt Tejun Heo
2020-09-01 18:52 ` [PATCH 08/27] blk-iocost: s/HWEIGHT_WHOLE/WEIGHT_ONE/g 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 ` [PATCH 14/27] blk-iocost: calculate iocg->usages[] from iocg->local_stat.usage_us 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 ` [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 ` [PATCH 21/27] blk-iocost: revamp debt handling 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 ` [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
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