From: Tejun Heo <tj@kernel.org>
To: axboe@kernel.dk, vgoyal@redhat.com
Cc: ctalbott@google.com, rni@google.com,
linux-kernel@vger.kernel.org, Tejun Heo <tj@kernel.org>
Subject: [PATCH 06/16] block: extend queue bypassing to cover blkcg policies
Date: Wed, 1 Feb 2012 12:50:19 -0800 [thread overview]
Message-ID: <1328129429-11823-7-git-send-email-tj@kernel.org> (raw)
In-Reply-To: <1328129429-11823-1-git-send-email-tj@kernel.org>
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
next prev parent reply other threads:[~2012-02-01 20:53 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-01 20:50 [PATCHSET] blkcg: kill policy node and blkg->dev, take#4 Tejun Heo
2012-02-01 20:50 ` [PATCH 01/16] blkcg: make CONFIG_BLK_CGROUP bool Tejun Heo
2012-02-02 6:53 ` Li Zefan
2012-02-02 17:14 ` Tejun Heo
2012-02-01 20:50 ` [PATCH 02/16] cfq: don't register propio policy if !CONFIG_CFQ_GROUP_IOSCHED Tejun Heo
2012-02-01 20:50 ` [PATCH 03/16] elevator: clear auxiliary data earlier during elevator switch Tejun Heo
2012-02-01 20:50 ` [PATCH 04/16] elevator: make elevator_init_fn() return 0/-errno Tejun Heo
2012-02-01 20:50 ` [PATCH 05/16] block: implement blk_queue_bypass_start/end() Tejun Heo
2012-02-01 20:50 ` Tejun Heo [this message]
2012-02-01 20:50 ` [PATCH 07/16] blkcg: shoot down blkio_groups on elevator switch Tejun Heo
2012-02-01 20:50 ` [PATCH 08/16] blkcg: move rcu_read_lock() outside of blkio_group get functions Tejun Heo
2012-02-01 20:50 ` [PATCH 09/16] blkcg: update blkg get functions take blkio_cgroup as parameter Tejun Heo
2012-02-01 20:50 ` [PATCH 10/16] blkcg: use q and plid instead of opaque void * for blkio_group association Tejun Heo
2012-02-01 20:50 ` [PATCH 11/16] blkcg: add blkio_policy[] array and allow one policy per policy ID Tejun Heo
2012-02-01 20:50 ` [PATCH 12/16] blkcg: use the usual get blkg path for root blkio_group Tejun Heo
2012-02-01 20:50 ` [PATCH 13/16] blkcg: factor out blkio_group creation Tejun Heo
2012-02-01 20:50 ` [PATCH 14/16] blkcg: don't allow or retain configuration of missing devices Tejun Heo
2012-02-01 20:50 ` [PATCH 15/16] blkcg: kill blkio_policy_node Tejun Heo
2012-02-01 20:50 ` [PATCH 16/16] blkcg: kill the mind-bending blkg->dev Tejun Heo
-- strict thread matches above, loose matches on Subject: below --
2012-01-23 23:09 [PATCHSET] blkcg: kill policy node and blkg->dev, take#3 Tejun Heo
2012-01-23 23:09 ` [PATCH 06/16] block: extend queue bypassing to cover blkcg policies Tejun Heo
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