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From: Yu Kuai <yukuai3@huawei.com>
To: <paolo.valente@linaro.org>, <axboe@kernel.dk>
Cc: <linux-block@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<yukuai3@huawei.com>, <yi.zhang@huawei.com>
Subject: [PATCH 2/3] block, bfq: add support to record request size information
Date: Wed, 14 Jul 2021 17:45:28 +0800	[thread overview]
Message-ID: <20210714094529.758808-3-yukuai3@huawei.com> (raw)
In-Reply-To: <20210714094529.758808-1-yukuai3@huawei.com>

If bfq keep dispatching requests with same size, the following
information are stored if CONFIG_BFQ_GROUP_IOSCHED is enabled:

1) the size
2) the count of requests
3) when the first request was dispatched

These will be used in later patch to support concurrent sync
io in such situation.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
 block/bfq-iosched.c | 15 +++++++++++++++
 block/bfq-iosched.h | 16 ++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 2768a4c1cc45..e5a1093ec30a 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -4920,6 +4920,20 @@ static bool bfq_has_work(struct blk_mq_hw_ctx *hctx)
 		bfq_tot_busy_queues(bfqd) > 0;
 }
 
+static void bfq_update_dispatch_size_info(struct bfq_data *bfqd,
+					  unsigned int size)
+{
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+	if (bfqd->dispatch_size == size) {
+		bfqd->dispatch_count++;
+	} else {
+		bfqd->dispatch_size = size;
+		bfqd->dispatch_count = 1;
+		bfqd->dispatch_time = jiffies;
+	}
+#endif
+}
+
 static struct request *__bfq_dispatch_request(struct blk_mq_hw_ctx *hctx)
 {
 	struct bfq_data *bfqd = hctx->queue->elevator->elevator_data;
@@ -5003,6 +5017,7 @@ static struct request *__bfq_dispatch_request(struct blk_mq_hw_ctx *hctx)
 		bfqd->rq_in_driver++;
 start_rq:
 		rq->rq_flags |= RQF_STARTED;
+		bfq_update_dispatch_size_info(bfqd, blk_rq_bytes(rq));
 	}
 exit:
 	return rq;
diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index 99c2a3cb081e..4b9d95447a50 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -768,6 +768,22 @@ struct bfq_data {
 	 * function)
 	 */
 	unsigned int word_depths[2][2];
+
+#ifdef CONFIG_BFQ_GROUP_IOSCHED
+	/* the size of last dispatched request */
+	unsigned int dispatch_size;
+	/*
+	 * If bfq keep dispatching requests with same size, this store the
+	 * count of requests. We use unsigned long here, so we don't care
+	 * about overflow.
+	 */
+	unsigned long dispatch_count;
+	/*
+	 * If bfq keep dispatching requests with same size, this store the
+	 * time when the first request was dispatched.
+	 */
+	unsigned long dispatch_time;
+#endif
 };
 
 enum bfqq_state_flags {
-- 
2.31.1


  parent reply	other threads:[~2021-07-14  9:37 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-14  9:45 [PATCH 0/3] optimize the queue idle judgment Yu Kuai
2021-07-14  9:45 ` [PATCH 1/3] block, bfq: do not idle if only one cgroup is activated Yu Kuai
2021-07-24  7:12   ` Paolo Valente
2021-07-26  1:15     ` yukuai (C)
2021-07-31  7:10     ` yukuai (C)
2021-08-03  7:07       ` Paolo Valente
2021-08-03 11:30         ` yukuai (C)
2021-07-14  9:45 ` Yu Kuai [this message]
2021-07-14  9:45 ` [PATCH 3/3] block, bfq: consider request size in bfq_asymmetric_scenario() Yu Kuai
2021-07-20 12:33 ` [PATCH 0/3] optimize the queue idle judgment yukuai (C)

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