[PATCH v2 3/4] block, bfq: add support to record request size information
From: Yu Kuai <hidden>
Date: 2021-08-06 01:57:46
Also in:
lkml
Subsystem:
bfq i/o scheduler, block layer, the rest · Maintainers:
Yu Kuai, Jens Axboe, Linus Torvalds
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 <redacted> --- 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 a780205a1be4..7df3fc0ef4ef 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c@@ -4936,6 +4936,20 @@ 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;
@@ -5019,6 +5033,7 @@ 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 610769214f72..9ab498839e7c 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h@@ -777,6 +777,22 @@ 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