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@xxxxxxxxxx>
---
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
