xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

block: get rid of QUEUE_FLAG_REENTER

Browse Source 
We are currently using this flag to check whether it's safe
to call into ->request_fn(). If it is set, we punt to kblockd.
But we get a lot of false positives and excessive punts to
kblockd, which hurts performance.

The only real abuser of this infrastructure is SCSI. So export
the async queue run and convert SCSI over to use that. There's
room for improvement in that SCSI need not always use the async
call, but this fixes our performance issue and they can fix that
up in due time.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This commit is contained in:
Jens Axboe
2011-04-19 13:32:46 +02:00
parent 5f45c69589
commit c21e6beba8
5 changed files with 20 additions and 54 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/scsi/scsi_transport_fc.c
View File

@@ -3816,28 +3816,17 @@ fail_host_msg:
static void
fc_bsg_goose_queue(struct fc_rport *rport)
{
int flagset;
unsigned long flags;
if (!rport->rqst_q)
return;
/*
* This get/put dance makes no sense
*/
get_device(&rport->dev);
spin_lock_irqsave(rport->rqst_q->queue_lock, flags);
flagset = test_bit(QUEUE_FLAG_REENTER, &rport->rqst_q->queue_flags) &&
!test_bit(QUEUE_FLAG_REENTER, &rport->rqst_q->queue_flags);
if (flagset)
queue_flag_set(QUEUE_FLAG_REENTER, rport->rqst_q);
__blk_run_queue(rport->rqst_q);
if (flagset)
queue_flag_clear(QUEUE_FLAG_REENTER, rport->rqst_q);
spin_unlock_irqrestore(rport->rqst_q->queue_lock, flags);
blk_run_queue_async(rport->rqst_q);
put_device(&rport->dev);
}
/**
* fc_bsg_rport_dispatch - process rport bsg requests and dispatch to LLDD
* @q: rport request queue