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drbd: performance - don't lose unplug events

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Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This commit is contained in:
Lars Ellenberg 2009-11-03 02:22:06 +01:00 committed by Philipp Reisner
parent e656ec8ae2
commit 83c38830b0
1 changed files with 6 additions and 1 deletions
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7
drivers/block/drbd/drbd_req.c
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@ -505,7 +505,7 @@ void __req_mod(struct drbd_request *req, enum drbd_req_event what,
* corresponding hlist_del is in _req_may_be_done() */
hlist_add_head(&req->colision, ar_hash_slot(mdev, req->sector));
set_bit(UNPLUG_REMOTE, &mdev->flags); /* why? */
set_bit(UNPLUG_REMOTE, &mdev->flags);
D_ASSERT(req->rq_state & RQ_NET_PENDING);
req->rq_state |= RQ_NET_QUEUED;
@ -536,6 +536,11 @@ void __req_mod(struct drbd_request *req, enum drbd_req_event what,
*
* Add req to the (now) current epoch (barrier). */
/* otherwise we may lose an unplug, which may cause some remote
* io-scheduler timeout to expire, increasing maximum latency,
* hurting performance. */
set_bit(UNPLUG_REMOTE, &mdev->flags);
/* see drbd_make_request_common,
* just after it grabs the req_lock */
D_ASSERT(test_bit(CREATE_BARRIER, &mdev->flags) == 0);