[PATCH v2 2/2] block: share request flush fields with elevator_private
From: Mike Snitzer <hidden>
Date: 2011-02-01 22:46:33
Also in:
lkml
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
Flush requests are never put on the IO scheduler. Convert request structure's elevator_private* into an array and have the flush fields share a union with it. Reclaim the space lost in 'struct request' by moving 'completion_data' back in the union with 'rb_node'. Signed-off-by: Mike Snitzer <redacted> --- block/cfq-iosched.c | 18 +++++++++--------- block/elevator.c | 2 +- include/linux/blkdev.h | 23 ++++++++++++----------- 3 files changed, 22 insertions(+), 21 deletions(-)
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 501ffdf..8692958 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c@@ -54,9 +54,9 @@ static const int cfq_hist_divisor = 4; #define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8) #define RQ_CIC(rq) \ - ((struct cfq_io_context *) (rq)->elevator_private) -#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2) -#define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elevator_private3) + ((struct cfq_io_context *) (rq)->elevator_private[0]) +#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private[1]) +#define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elevator_private[2]) static struct kmem_cache *cfq_pool; static struct kmem_cache *cfq_ioc_pool;
@@ -3609,12 +3609,12 @@ static void cfq_put_request(struct request *rq) put_io_context(RQ_CIC(rq)->ioc); - rq->elevator_private = NULL; - rq->elevator_private2 = NULL; + rq->elevator_private[0] = NULL; + rq->elevator_private[1] = NULL; /* Put down rq reference on cfqg */ cfq_put_cfqg(RQ_CFQG(rq)); - rq->elevator_private3 = NULL; + rq->elevator_private[2] = NULL; cfq_put_queue(cfqq); }
@@ -3702,9 +3702,9 @@ new_queue: cfqq->allocated[rw]++; cfqq->ref++; - rq->elevator_private = cic; - rq->elevator_private2 = cfqq; - rq->elevator_private3 = cfq_ref_get_cfqg(cfqq->cfqg); + rq->elevator_private[0] = cic; + rq->elevator_private[1] = cfqq; + rq->elevator_private[2] = cfq_ref_get_cfqg(cfqq->cfqg); spin_unlock_irqrestore(q->queue_lock, flags);
diff --git a/block/elevator.c b/block/elevator.c
index 270e097..f98e92e 100644
--- a/block/elevator.c
+++ b/block/elevator.c@@ -764,7 +764,7 @@ int elv_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask) if (e->ops->elevator_set_req_fn) return e->ops->elevator_set_req_fn(q, rq, gfp_mask); - rq->elevator_private = NULL; + rq->elevator_private[0] = NULL; return 0; }
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 8a082a5..e3ee74f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h@@ -99,25 +99,26 @@ struct request { /* * The rb_node is only used inside the io scheduler, requests * are pruned when moved to the dispatch queue. So let the - * flush fields share space with the rb_node. + * completion_data share space with the rb_node. */ union { struct rb_node rb_node; /* sort/lookup */ - struct { - unsigned int seq; - struct list_head list; - } flush; + void *completion_data; }; - void *completion_data;