From: brookxu <brookxu.cn@gmail.com>
To: paolo.valente@linaro.org, axboe@kernel.dk, tj@kernel.org
Cc: linux-block@vger.kernel.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [RFC PATCH 8/8] bfq: optimize the calculation of bfq_weight_to_ioprio()
Date: Mon, 8 Mar 2021 20:00:21 +0800 [thread overview]
Message-ID: <cbd1e689ca0010c3d437f22c904f10b123e6b1f4.1615203034.git.brookxu@tencent.com> (raw)
In-Reply-To: <cover.1615203034.git.brookxu@tencent.com>
In-Reply-To: <cover.1615203034.git.brookxu@tencent.com>
From: Chunguang Xu <brookxu@tencent.com>
From: Chunguang Xu <brookxu@tencent.com>
The value range of ioprio is [0, 7], but the result of
bfq_weight_to_ioprio() may exceed this range, so simple
optimization is required.
Signed-off-by: Chunguang Xu <brookxu@tencent.com>
---
block/bfq-wf2q.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c
index 850a8e2f0bda..1d565daf516f 100644
--- a/block/bfq-wf2q.c
+++ b/block/bfq-wf2q.c
@@ -536,8 +536,9 @@ unsigned short bfq_ioprio_to_weight(int ioprio)
*/
static unsigned short bfq_weight_to_ioprio(int weight)
{
- return max_t(int, 0,
- IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF - weight);
+ int ioprio = IOPRIO_BE_NR - weight / BFQ_WEIGHT_CONVERSION_COEFF;
+
+ return ioprio < 0 ? 0 : min_t(int, ioprio, IOPRIO_BE_NR - 1);
}
static void bfq_get_entity(struct bfq_entity *entity)
--
2.30.0
prev parent reply other threads:[~2021-03-08 12:01 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-08 12:00 [RFC PATCH 0/8] bfq: introduce bfq.ioprio for cgroup brookxu
2021-03-08 12:00 ` [RFC PATCH 1/8] bfq: introduce bfq_entity_to_bfqg helper method brookxu
2021-03-08 12:00 ` [RFC PATCH 2/8] bfq: limit the IO depth of idle_class to 1 brookxu
2021-03-08 12:00 ` [RFC PATCH 3/8] bfq: keep the minimun bandwidth for be_class brookxu
2021-03-08 12:00 ` [RFC PATCH 4/8] bfq: expire bfqq if a higher priority class is waiting brookxu
2021-03-08 12:00 ` [RFC PATCH 5/8] bfq: introduce bfq.ioprio for cgroup brookxu
2021-03-08 12:00 ` [RFC PATCH 6/8] bfq: convert the type of bfq_group.bfqd to bfq_data* brookxu
2021-03-08 12:00 ` [RFC PATCH 7/8] bfq: remove unnecessary initialization logic brookxu
2021-03-08 12:00 ` brookxu [this message]
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