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authorMing Lei <ming.lei@redhat.com>2019-10-25 14:58:55 +0800
committerMartin K. Petersen <martin.petersen@oracle.com>2019-11-01 20:12:50 -0400
commit6eb045e092efefafc6687409a6fa6d1dabf0fb69 (patch)
treeaeb333b78b8514f84daa88f6e431ea69ab51b22c /drivers/scsi/scsi.c
parent7f674c38a38e056bb33d1d67700410c3f3124d34 (diff)
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scsi: core: avoid host-wide host_busy counter for scsi_mq
It isn't necessary to check the host depth in scsi_queue_rq() any more since it has been respected by blk-mq before calling scsi_queue_rq() via getting driver tag. Lots of LUNs may attach to same host and per-host IOPS may reach millions, so we should avoid expensive atomic operations on the host-wide counter in the IO path. This patch implements scsi_host_busy() via blk_mq_tagset_busy_iter() with one scsi command state for reading the count of busy IOs for scsi_mq. It is observed that IOPS is increased by 15% in IO test on scsi_debug (32 LUNs, 32 submit queues, 1024 can_queue, libaio/dio) in a dual-socket system. Cc: Jens Axboe <axboe@kernel.dk> Cc: Ewan D. Milne <emilne@redhat.com> Cc: Omar Sandoval <osandov@fb.com>, Cc: "Martin K. Petersen" <martin.petersen@oracle.com>, Cc: James Bottomley <james.bottomley@hansenpartnership.com>, Cc: Christoph Hellwig <hch@lst.de>, Cc: Kashyap Desai <kashyap.desai@broadcom.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Laurence Oberman <loberman@redhat.com> Cc: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20191025065855.6309-1-ming.lei@redhat.com Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/scsi.c')
-rw-r--r--drivers/scsi/scsi.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 4f76841a7038..adfe8b3693d5 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -186,7 +186,7 @@ void scsi_finish_command(struct scsi_cmnd *cmd)
struct scsi_driver *drv;
unsigned int good_bytes;
- scsi_device_unbusy(sdev);
+ scsi_device_unbusy(sdev, cmd);
/*
* Clear the flags that say that the device/target/host is no longer