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| author | Tejun Heo <tj@kernel.org> | 2015-08-18 14:55:03 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2015-08-18 15:49:16 -0700 |
| commit | 322731ed0dd2d8a7f11307e0444257f48580a0de (patch) | |
| tree | 536ae950d92b337f3896cb37acc8d3bf5c05ac14 /block/cfq-iosched.c | |
| parent | 2da8de0bb799bf2bdfa893e5a1e294eb6bafba62 (diff) | |
| download | linux-322731ed0dd2d8a7f11307e0444257f48580a0de.tar.gz linux-322731ed0dd2d8a7f11307e0444257f48580a0de.tar.bz2 linux-322731ed0dd2d8a7f11307e0444257f48580a0de.zip | |
cfq-iosched: move cfq_group determination from cfq_find_alloc_queue() to cfq_get_queue()
This is necessary for making async cfq_cgroups per-cfq_group instead
of per-cfq_data. While this change makes cfq_get_queue() perform RCU
locking and look up cfq_group even when it reuses async queue, the
extra overhead is extremely unlikely to be noticeable given that this
is already sitting behind cic->cfqq[] cache and the overall cost of
cfq operation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/cfq-iosched.c')
| -rw-r--r-- | block/cfq-iosched.c | 28 |
1 files changed, 12 insertions, 16 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 146b03d64b7e..f3ea8a198def 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -3641,21 +3641,10 @@ static inline void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio) { #endif /* CONFIG_CFQ_GROUP_IOSCHED */ static struct cfq_queue * -cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, - struct bio *bio) +cfq_find_alloc_queue(struct cfq_data *cfqd, struct cfq_group *cfqg, bool is_sync, + struct cfq_io_cq *cic, struct bio *bio) { - struct blkcg *blkcg; struct cfq_queue *cfqq; - struct cfq_group *cfqg; - - rcu_read_lock(); - - blkcg = bio_blkcg(bio); - cfqg = cfq_lookup_create_cfqg(cfqd, blkcg); - if (!cfqg) { - cfqq = &cfqd->oom_cfqq; - goto out; - } cfqq = cic_to_cfqq(cic, is_sync); @@ -3675,8 +3664,6 @@ cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, } else cfqq = &cfqd->oom_cfqq; } -out: - rcu_read_unlock(); return cfqq; } @@ -3706,6 +3693,14 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, int ioprio = IOPRIO_PRIO_DATA(cic->ioprio); struct cfq_queue **async_cfqq; struct cfq_queue *cfqq; + struct cfq_group *cfqg; + + rcu_read_lock(); + cfqg = cfq_lookup_create_cfqg(cfqd, bio_blkcg(bio)); + if (!cfqg) { + cfqq = &cfqd->oom_cfqq; + goto out; + } if (!is_sync) { if (!ioprio_valid(cic->ioprio)) { @@ -3719,7 +3714,7 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, goto out; } - cfqq = cfq_find_alloc_queue(cfqd, is_sync, cic, bio); + cfqq = cfq_find_alloc_queue(cfqd, cfqg, is_sync, cic, bio); /* * pin the queue now that it's allocated, scheduler exit will prune it @@ -3730,6 +3725,7 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, } out: cfqq->ref++; + rcu_read_unlock(); return cfqq; } |