Messages in this thread Patch in this message | | | From | Tejun Heo <> | Subject | [PATCH 06/16] block: extend queue bypassing to cover blkcg policies | Date | Mon, 23 Jan 2012 15:09:43 -0800 |
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From: Tejun Heo <tejun@google.com>
Extend queue bypassing such that dying queue is always bypassing and blk-throttle is drained on bypass. With blkcg policies updated to test blk_queue_bypass() instead of blk_queue_dead(), this ensures that no bio or request is held by or going through blkcg policies on a bypassing queue.
This will be used to implement blkg cleanup on elevator switches and policy changes.
Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> --- block/blk-core.c | 12 ++++++++---- block/blk-throttle.c | 4 ++-- 2 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c index c2e39de..c6c61c0 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -366,8 +366,7 @@ void blk_drain_queue(struct request_queue *q, bool drain_all) spin_lock_irq(q->queue_lock); elv_drain_elevator(q); - if (drain_all) - blk_throtl_drain(q); + blk_throtl_drain(q); /* * This function might be called on a queue which failed @@ -408,8 +407,8 @@ void blk_drain_queue(struct request_queue *q, bool drain_all) * * In bypass mode, only the dispatch FIFO queue of @q is used. This * function makes @q enter bypass mode and drains all requests which were - * issued before. On return, it's guaranteed that no request has ELVPRIV - * set. + * throttled or issued before. On return, it's guaranteed that no request + * is being throttled or has ELVPRIV set. */ void blk_queue_bypass_start(struct request_queue *q) { @@ -454,6 +453,11 @@ void blk_cleanup_queue(struct request_queue *q) queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q); spin_lock_irq(lock); + + /* dead queue is permanently in bypass mode till released */ + q->bypass_depth++; + queue_flag_set(QUEUE_FLAG_BYPASS, q); + queue_flag_set(QUEUE_FLAG_NOMERGES, q); queue_flag_set(QUEUE_FLAG_NOXMERGES, q); queue_flag_set(QUEUE_FLAG_DEAD, q); diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 5eed6a7..702c0e6 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -310,7 +310,7 @@ static struct throtl_grp * throtl_get_tg(struct throtl_data *td) struct request_queue *q = td->queue; /* no throttling for dead queue */ - if (unlikely(blk_queue_dead(q))) + if (unlikely(blk_queue_bypass(q))) return NULL; rcu_read_lock(); @@ -335,7 +335,7 @@ static struct throtl_grp * throtl_get_tg(struct throtl_data *td) spin_lock_irq(q->queue_lock); /* Make sure @q is still alive */ - if (unlikely(blk_queue_dead(q))) { + if (unlikely(blk_queue_bypass(q))) { kfree(tg); return NULL; } -- 1.7.7.3
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