From 7e5a8794492e43e9eebb68a98a23be055888ccd0 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 14 Dec 2011 00:33:42 +0100 Subject: block, cfq: move io_cq exit/release to blk-ioc.c With kmem_cache managed by blk-ioc, io_cq exit/release can be moved to blk-ioc too. The odd ->io_cq->exit/release() callbacks are replaced with elevator_ops->elevator_exit_icq_fn() with unlinking from both ioc and q, and freeing automatically handled by blk-ioc. The elevator operation only need to perform exit operation specific to the elevator - in cfq's case, exiting the cfqq's. Also, clearing of io_cq's on q detach is moved to block core and automatically performed on elevator switch and q release. Because the q io_cq points to might be freed before RCU callback for the io_cq runs, blk-ioc code should remember to which cache the io_cq needs to be freed when the io_cq is released. New field io_cq->__rcu_icq_cache is added for this purpose. As both the new field and rcu_head are used only after io_cq is released and the q/ioc_node fields aren't, they are put into unions. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 47 ++--------------------------------------------- 1 file changed, 2 insertions(+), 45 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 06e59abcb57f..f6d315551496 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -2674,26 +2674,6 @@ static void cfq_put_queue(struct cfq_queue *cfqq) cfq_put_cfqg(cfqg); } -static void cfq_icq_free_rcu(struct rcu_head *head) -{ - kmem_cache_free(cfq_icq_pool, - icq_to_cic(container_of(head, struct io_cq, rcu_head))); -} - -static void cfq_icq_free(struct io_cq *icq) -{ - call_rcu(&icq->rcu_head, cfq_icq_free_rcu); -} - -static void cfq_release_icq(struct io_cq *icq) -{ - struct io_context *ioc = icq->ioc; - - radix_tree_delete(&ioc->icq_tree, icq->q->id); - hlist_del(&icq->ioc_node); - cfq_icq_free(icq); -} - static void cfq_put_cooperator(struct cfq_queue *cfqq) { struct cfq_queue *__cfqq, *next; @@ -2731,17 +2711,6 @@ static void cfq_exit_icq(struct io_cq *icq) { struct cfq_io_cq *cic = icq_to_cic(icq); struct cfq_data *cfqd = cic_to_cfqd(cic); - struct io_context *ioc = icq->ioc; - - list_del_init(&icq->q_node); - - /* - * Both setting lookup hint to and clearing it from @icq are done - * under queue_lock. If it's not pointing to @icq now, it never - * will. Hint assignment itself can race safely. - */ - if (rcu_dereference_raw(ioc->icq_hint) == icq) - rcu_assign_pointer(ioc->icq_hint, NULL); if (cic->cfqq[BLK_RW_ASYNC]) { cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]); @@ -2764,8 +2733,6 @@ static struct cfq_io_cq *cfq_alloc_cic(struct cfq_data *cfqd, gfp_t gfp_mask) cic->ttime.last_end_request = jiffies; INIT_LIST_HEAD(&cic->icq.q_node); INIT_HLIST_NODE(&cic->icq.ioc_node); - cic->icq.exit = cfq_exit_icq; - cic->icq.release = cfq_release_icq; } return cic; @@ -3034,7 +3001,7 @@ out: if (ret) printk(KERN_ERR "cfq: icq link failed!\n"); if (icq) - cfq_icq_free(icq); + kmem_cache_free(cfq_icq_pool, icq); return ret; } @@ -3774,17 +3741,6 @@ static void cfq_exit_queue(struct elevator_queue *e) if (cfqd->active_queue) __cfq_slice_expired(cfqd, cfqd->active_queue, 0); - while (!list_empty(&q->icq_list)) { - struct io_cq *icq = list_entry(q->icq_list.next, - struct io_cq, q_node); - struct io_context *ioc = icq->ioc; - - spin_lock(&ioc->lock); - cfq_exit_icq(icq); - cfq_release_icq(icq); - spin_unlock(&ioc->lock); - } - cfq_put_async_queues(cfqd); cfq_release_cfq_groups(cfqd); @@ -4019,6 +3975,7 @@ static struct elevator_type iosched_cfq = { .elevator_completed_req_fn = cfq_completed_request, .elevator_former_req_fn = elv_rb_former_request, .elevator_latter_req_fn = elv_rb_latter_request, + .elevator_exit_icq_fn = cfq_exit_icq, .elevator_set_req_fn = cfq_set_request, .elevator_put_req_fn = cfq_put_request, .elevator_may_queue_fn = cfq_may_queue, -- cgit v1.2.1