block: share request flush fields with elevator_private
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 <snitzer@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
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@ -54,9 +54,9 @@ static const int cfq_hist_divisor = 4;
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#define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8)
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#define RQ_CIC(rq) \
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((struct cfq_io_context *) (rq)->elevator_private)
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#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2)
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#define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elevator_private3)
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((struct cfq_io_context *) (rq)->elevator_private[0])
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#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private[1])
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#define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elevator_private[2])
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static struct kmem_cache *cfq_pool;
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static struct kmem_cache *cfq_ioc_pool;
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@ -3589,12 +3589,12 @@ static void cfq_put_request(struct request *rq)
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put_io_context(RQ_CIC(rq)->ioc);
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rq->elevator_private = NULL;
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rq->elevator_private2 = NULL;
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rq->elevator_private[0] = NULL;
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rq->elevator_private[1] = NULL;
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/* Put down rq reference on cfqg */
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cfq_put_cfqg(RQ_CFQG(rq));
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rq->elevator_private3 = NULL;
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rq->elevator_private[2] = NULL;
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cfq_put_queue(cfqq);
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}
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@ -3685,9 +3685,9 @@ new_queue:
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spin_unlock_irqrestore(q->queue_lock, flags);
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rq->elevator_private = cic;
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rq->elevator_private2 = cfqq;
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rq->elevator_private3 = cfq_ref_get_cfqg(cfqq->cfqg);
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rq->elevator_private[0] = cic;
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rq->elevator_private[1] = cfqq;
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rq->elevator_private[2] = cfq_ref_get_cfqg(cfqq->cfqg);
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return 0;
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queue_fail:
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@ -764,7 +764,7 @@ int elv_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
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if (e->ops->elevator_set_req_fn)
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return e->ops->elevator_set_req_fn(q, rq, gfp_mask);
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rq->elevator_private = NULL;
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rq->elevator_private[0] = NULL;
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return 0;
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}
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@ -99,25 +99,26 @@ struct request {
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/*
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* The rb_node is only used inside the io scheduler, requests
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* are pruned when moved to the dispatch queue. So let the
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* flush fields share space with the rb_node.
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* completion_data share space with the rb_node.
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*/
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union {
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struct rb_node rb_node; /* sort/lookup */
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struct {
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unsigned int seq;
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struct list_head list;
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} flush;
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void *completion_data;
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};
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void *completion_data;
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/*
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* Three pointers are available for the IO schedulers, if they need
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* more they have to dynamically allocate it.
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* more they have to dynamically allocate it. Flush requests are
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* never put on the IO scheduler. So let the flush fields share
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* space with the three elevator_private pointers.
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*/
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void *elevator_private;
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void *elevator_private2;
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void *elevator_private3;
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union {
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void *elevator_private[3];
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struct {
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unsigned int seq;
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struct list_head list;
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} flush;
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};
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struct gendisk *rq_disk;
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unsigned long start_time;
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