diff options
author | 2013-05-14 13:52:38 -0700 | |
---|---|---|
committer | 2013-05-14 13:52:38 -0700 | |
commit | 2e48a530a3a7daebd0cc17866304a36d39b611de (patch) | |
tree | 6fc47a1a5b74966ff19f5287dc58fbcf3a541ee6 /block | |
parent | blk-throttle: make tg_dispatch_one_bio() ready for hierarchy (diff) | |
download | linux-2e48a530a3a7daebd0cc17866304a36d39b611de.tar.gz linux-2e48a530a3a7daebd0cc17866304a36d39b611de.tar.bz2 linux-2e48a530a3a7daebd0cc17866304a36d39b611de.zip |
blk-throttle: make throtl_pending_timer_fn() ready for hierarchy
throtl_pending_timer_fn() currently assumes that the parent_sq is the
top level one and the bio's dispatched are ready to be issued;
however, this assumption will be wrong with proper hierarchy support.
This patch makes the following changes to make
throtl_pending_timer_fn() ready for hiearchy.
* If the parent_sq isn't the top-level one, update the parent
throtl_grp's dispatch time and schedule the next dispatch as
necessary. If the parent's dispatch time is now, repeat the
function for the parent throtl_grp.
* If the parent_sq is the top-level one, kick issue work_item as
before.
* The debug message printed by throtl_log() now prints out the
service_queue's nr_queued[] instead of the total nr_queued as the
latter becomes uninteresting and misleading with hierarchical
dispatch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Diffstat (limited to 'block')
-rw-r--r-- | block/blk-throttle.c | 40 |
1 files changed, 33 insertions, 7 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 04202617fda5..bc65077f6e43 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -952,23 +952,33 @@ static int throtl_select_dispatch(struct throtl_service_queue *parent_sq) * This timer is armed when a child throtl_grp with active bio's become * pending and queued on the service_queue's pending_tree and expires when * the first child throtl_grp should be dispatched. This function - * dispatches bio's from the children throtl_grps and kicks - * throtl_data->dispatch_work if there are bio's ready to be issued. + * dispatches bio's from the children throtl_grps to the parent + * service_queue. + * + * If the parent's parent is another throtl_grp, dispatching is propagated + * by either arming its pending_timer or repeating dispatch directly. If + * the top-level service_tree is reached, throtl_data->dispatch_work is + * kicked so that the ready bio's are issued. */ static void throtl_pending_timer_fn(unsigned long arg) { struct throtl_service_queue *sq = (void *)arg; + struct throtl_grp *tg = sq_to_tg(sq); struct throtl_data *td = sq_to_td(sq); struct request_queue *q = td->queue; - bool dispatched = false; + struct throtl_service_queue *parent_sq; + bool dispatched; int ret; spin_lock_irq(q->queue_lock); +again: + parent_sq = sq->parent_sq; + dispatched = false; while (true) { throtl_log(sq, "dispatch nr_queued=%u read=%u write=%u", - td->nr_queued[READ] + td->nr_queued[WRITE], - td->nr_queued[READ], td->nr_queued[WRITE]); + sq->nr_queued[READ] + sq->nr_queued[WRITE], + sq->nr_queued[READ], sq->nr_queued[WRITE]); ret = throtl_select_dispatch(sq); if (ret) { @@ -985,9 +995,25 @@ static void throtl_pending_timer_fn(unsigned long arg) spin_lock_irq(q->queue_lock); } - if (dispatched) - queue_work(kthrotld_workqueue, &td->dispatch_work); + if (!dispatched) + goto out_unlock; + if (parent_sq) { + /* @parent_sq is another throl_grp, propagate dispatch */ + if (tg->flags & THROTL_TG_WAS_EMPTY) { + tg_update_disptime(tg); + if (!throtl_schedule_next_dispatch(parent_sq, false)) { + /* window is already open, repeat dispatching */ + sq = parent_sq; + tg = sq_to_tg(sq); + goto again; + } + } + } else { + /* reached the top-level, queue issueing */ + queue_work(kthrotld_workqueue, &td->dispatch_work); + } +out_unlock: spin_unlock_irq(q->queue_lock); } |