From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@fb.com>,
linux-block@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>,
Mike Snitzer <snitzer@redhat.com>,
dm-devel@redhat.com
Cc: Bart Van Assche <bart.vanassche@sandisk.com>,
Laurence Oberman <loberman@redhat.com>,
Paolo Valente <paolo.valente@linaro.org>,
Oleksandr Natalenko <oleksandr@natalenko.name>,
Tom Nguyen <tom81094@gmail.com>,
linux-kernel@vger.kernel.org, Omar Sandoval <osandov@fb.com>,
Ming Lei <ming.lei@redhat.com>
Subject: [PATCH V5 3/8] block: introduce rqhash helpers
Date: Sat, 30 Sep 2017 19:26:50 +0800 [thread overview]
Message-ID: <20170930112655.31451-4-ming.lei@redhat.com> (raw)
In-Reply-To: <20170930112655.31451-1-ming.lei@redhat.com>
We need this helpers for supporting to use hashtable to improve
bio merge from sw queue in the following patches.
No functional change.
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Tom Nguyen <tom81094@gmail.com>
Tested-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/blk.h | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
block/elevator.c | 36 +++++++-----------------------------
2 files changed, 59 insertions(+), 29 deletions(-)
diff --git a/block/blk.h b/block/blk.h
index fcb9775b997d..eb3436d4a73f 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -146,6 +146,58 @@ static inline void blk_clear_rq_complete(struct request *rq)
*/
#define ELV_ON_HASH(rq) ((rq)->rq_flags & RQF_HASHED)
+/*
+ * Merge hash stuff.
+ */
+#define rq_hash_key(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
+
+#define bucket(head, key) &((head)[hash_min((key), ELV_HASH_BITS)])
+
+static inline void __rqhash_del(struct request *rq)
+{
+ hash_del(&rq->hash);
+ rq->rq_flags &= ~RQF_HASHED;
+}
+
+static inline void rqhash_del(struct request *rq)
+{
+ if (ELV_ON_HASH(rq))
+ __rqhash_del(rq);
+}
+
+static inline void rqhash_add(struct hlist_head *hash, struct request *rq)
+{
+ BUG_ON(ELV_ON_HASH(rq));
+ hlist_add_head(&rq->hash, bucket(hash, rq_hash_key(rq)));
+ rq->rq_flags |= RQF_HASHED;
+}
+
+static inline void rqhash_reposition(struct hlist_head *hash, struct request *rq)
+{
+ __rqhash_del(rq);
+ rqhash_add(hash, rq);
+}
+
+static inline struct request *rqhash_find(struct hlist_head *hash, sector_t offset)
+{
+ struct hlist_node *next;
+ struct request *rq = NULL;
+
+ hlist_for_each_entry_safe(rq, next, bucket(hash, offset), hash) {
+ BUG_ON(!ELV_ON_HASH(rq));
+
+ if (unlikely(!rq_mergeable(rq))) {
+ __rqhash_del(rq);
+ continue;
+ }
+
+ if (rq_hash_key(rq) == offset)
+ return rq;
+ }
+
+ return NULL;
+}
+
void blk_insert_flush(struct request *rq);
static inline struct request *__elv_next_request(struct request_queue *q)
diff --git a/block/elevator.c b/block/elevator.c
index 153926a90901..824cc3e69ac3 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -47,11 +47,6 @@ static DEFINE_SPINLOCK(elv_list_lock);
static LIST_HEAD(elv_list);
/*
- * Merge hash stuff.
- */
-#define rq_hash_key(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
-
-/*
* Query io scheduler to see if the current process issuing bio may be
* merged with rq.
*/
@@ -268,14 +263,12 @@ EXPORT_SYMBOL(elevator_exit);
static inline void __elv_rqhash_del(struct request *rq)
{
- hash_del(&rq->hash);
- rq->rq_flags &= ~RQF_HASHED;
+ __rqhash_del(rq);
}
void elv_rqhash_del(struct request_queue *q, struct request *rq)
{
- if (ELV_ON_HASH(rq))
- __elv_rqhash_del(rq);
+ rqhash_del(rq);
}
EXPORT_SYMBOL_GPL(elv_rqhash_del);
@@ -283,37 +276,22 @@ void elv_rqhash_add(struct request_queue *q, struct request *rq)
{
struct elevator_queue *e = q->elevator;
- BUG_ON(ELV_ON_HASH(rq));
- hash_add(e->hash, &rq->hash, rq_hash_key(rq));
- rq->rq_flags |= RQF_HASHED;
+ rqhash_add(e->hash, rq);
}
EXPORT_SYMBOL_GPL(elv_rqhash_add);
void elv_rqhash_reposition(struct request_queue *q, struct request *rq)
{
- __elv_rqhash_del(rq);
- elv_rqhash_add(q, rq);
+ struct elevator_queue *e = q->elevator;
+
+ rqhash_reposition(e->hash, rq);
}
struct request *elv_rqhash_find(struct request_queue *q, sector_t offset)
{
struct elevator_queue *e = q->elevator;
- struct hlist_node *next;
- struct request *rq;
-
- hash_for_each_possible_safe(e->hash, rq, next, hash, offset) {
- BUG_ON(!ELV_ON_HASH(rq));
- if (unlikely(!rq_mergeable(rq))) {
- __elv_rqhash_del(rq);
- continue;
- }
-
- if (rq_hash_key(rq) == offset)
- return rq;
- }
-
- return NULL;
+ return rqhash_find(e->hash, offset);
}
/*
--
2.9.5
next prev parent reply other threads:[~2017-09-30 11:31 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-30 11:26 [PATCH V5 0/8] blk-mq: improve bio merge for none scheduler Ming Lei
2017-09-30 11:26 ` [PATCH V5 1/8] blk-mq-sched: introduce blk_mq_sched_queue_depth() Ming Lei
2017-09-30 11:26 ` [PATCH V5 2/8] blk-mq-sched: use q->queue_depth as hint for q->nr_requests Ming Lei
2017-09-30 11:26 ` Ming Lei [this message]
2017-10-03 9:15 ` [PATCH V5 3/8] block: introduce rqhash helpers Christoph Hellwig
2017-09-30 11:26 ` [PATCH V5 4/8] block: move actual bio merge code into __elv_merge Ming Lei
2017-10-03 9:16 ` Christoph Hellwig
2017-09-30 11:26 ` [PATCH V5 5/8] block: add check on elevator for supporting bio merge via hashtable from blk-mq sw queue Ming Lei
2017-10-03 9:17 ` Christoph Hellwig
2017-09-30 11:26 ` [PATCH V5 6/8] block: introduce .last_merge and .hash to blk_mq_ctx Ming Lei
2017-10-03 9:19 ` Christoph Hellwig
2017-09-30 11:26 ` [PATCH V5 7/8] blk-mq-sched: refactor blk_mq_sched_try_merge() Ming Lei
2017-10-03 9:20 ` Christoph Hellwig
2017-09-30 11:26 ` [PATCH V5 8/8] blk-mq: improve bio merge from blk-mq sw queue Ming Lei
2017-10-03 9:21 ` Christoph Hellwig
2017-10-09 4:28 ` Ming Lei
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