scsi: add use_cmd_list flag

Add a use_cmd_list flag in struct Scsi_Host to request keeping track of
all outstanding commands per device.

Default behaviour is not to keep track of cmd_list per sdev, as this may
introduce lock contention. (overhead is more on multi-node NUMA.), and
only enable it on the two drivers that need it.

Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Kashyap.Desai@avagotech.com
2014-08-20 19:24:33 +05:30
committed by Christoph Hellwig
parent 2eefd57b97
commit 64bdcbc449
4 changed files with 15 additions and 12 deletions

View File

@@ -680,6 +680,7 @@ struct Scsi_Host {
unsigned no_write_same:1;
unsigned use_blk_mq:1;
unsigned use_cmd_list:1;
/*
* Optional work queue to be utilized by the transport