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| author | Jens Axboe <jens.axboe@oracle.com> | 2007-04-18 20:01:57 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@nelson.home.kernel.dk> | 2007-04-30 09:01:22 +0200 |
| commit | 0c534e0a463e2eeafc97ba25ab23c14f3cdf2bdb (patch) | |
| tree | 20f3b12b05a853e9e52eaabead16a195d519501b /block/cfq-iosched.c | |
| parent | [PATCH] cfq-iosched: speed up rbtree handling (diff) | |
| download | linux-0c534e0a463e2eeafc97ba25ab23c14f3cdf2bdb.tar.xz linux-0c534e0a463e2eeafc97ba25ab23c14f3cdf2bdb.zip | |
cfq-iosched: sort RT queues into the rbtree
Currently CFQ does a linked insert into the current list for RT
queues. We can just factor the class into the rb insertion,
and then we don't have to treat RT queues in a special way. It's
faster, too.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/cfq-iosched.c')
| -rw-r--r-- | block/cfq-iosched.c | 27 |
1 files changed, 12 insertions, 15 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 55c476baa692..81c057eadfcc 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -471,7 +471,16 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, parent = *p; __cfqq = rb_entry(parent, struct cfq_queue, rb_node); - if (rb_key < __cfqq->rb_key) + /* + * sort RT queues first, we always want to give + * preference to them. after that, sort on the next + * service time. + */ + if (cfq_class_rt(cfqq) > cfq_class_rt(__cfqq)) + p = &(*p)->rb_left; + else if (cfq_class_rt(cfqq) < cfq_class_rt(__cfqq)) + p = &(*p)->rb_right; + else if (rb_key < __cfqq->rb_key) p = &(*p)->rb_left; else { p = &(*p)->rb_right; @@ -490,7 +499,6 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) { struct cfq_data *cfqd = cfqq->cfqd; - struct list_head *n; /* * Resorting requires the cfqq to be on the RR list already. @@ -500,25 +508,14 @@ static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) list_del_init(&cfqq->cfq_list); - if (cfq_class_rt(cfqq)) { - /* - * At to the front of the current list, but behind other - * RT queues. - */ - n = &cfqd->cur_rr; - while (n->next != &cfqd->cur_rr) - if (!cfq_class_rt(cfqq)) - break; - - list_add(&cfqq->cfq_list, n); - } else if (cfq_class_idle(cfqq)) { + if (cfq_class_idle(cfqq)) { /* * IDLE goes to the tail of the idle list */ list_add_tail(&cfqq->cfq_list, &cfqd->idle_rr); } else { /* - * So we get here, ergo the queue is a regular best-effort queue + * RT and BE queues, sort into the rbtree */ cfq_service_tree_add(cfqd, cfqq); } |