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| author | Christoph Hellwig <hch@infradead.org> | 2011-10-17 13:56:53 -0400 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2011-10-24 03:21:52 +0000 |
| commit | 35e0e757537b9239172e35db773dd062727fd612 (patch) | |
| tree | 3a54e1e426f1a962219325eac474b715a4699924 /include/target | |
| parent | 59aaad1ec44d9a77c32b873b001f31c5af47fcc7 (diff) | |
| download | lwn-35e0e757537b9239172e35db773dd062727fd612.tar.gz lwn-35e0e757537b9239172e35db773dd062727fd612.zip | |
target: use a workqueue for I/O completions
Instead of abusing the target processing thread for offloading I/O
completion in the backends to user context add a new workqueue. This means
completions can be processed as fast as available CPU time allows it,
including in parallel with other completions and more importantly I/O
submission or QUEUE FULL retries. This should give much better performance
especially on loaded systems.
As a fallout we can merge all the completed states into a single
one.
On the downside this change complicates lun reset handling a bit by
requiring us to cancel a work item only for those states that have it
initialized. The alternative would be to either always initialize the work
item to a dummy handler, or always use the same handler and do a switch on
the state. The long term solution will be a flag that says that the command
has an initialized work item, but that's only going to be useful once we
have more users.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'include/target')
| -rw-r--r-- | include/target/target_core_base.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h index 07104bf0a9c8..8e2c83d4fbad 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -86,9 +86,7 @@ enum transport_state_table { TRANSPORT_WRITE_PENDING = 3, TRANSPORT_PROCESS_WRITE = 4, TRANSPORT_PROCESSING = 5, - TRANSPORT_COMPLETE_OK = 6, - TRANSPORT_COMPLETE_FAILURE = 7, - TRANSPORT_COMPLETE_TIMEOUT = 8, + TRANSPORT_COMPLETE = 6, TRANSPORT_PROCESS_TMR = 9, TRANSPORT_ISTATE_PROCESSING = 11, TRANSPORT_NEW_CMD_MAP = 16, @@ -492,6 +490,8 @@ struct se_cmd { struct completion transport_lun_stop_comp; struct scatterlist *t_tasks_sg_chained; + struct work_struct work; + /* * Used for pre-registered fabric SGL passthrough WRITE and READ * with the special SCF_PASSTHROUGH_CONTIG_TO_SG case for TCM_Loop |