forked from luck/tmp_suning_uos_patched
a0044bdf60
Send as many I/O requests to the I/O thread as possible, even though it will still only handle one at a time. This provides an opportunity to reduce latency by starting one request before the previous one has been finished in the driver. Request handling is somewhat modernized by requesting sg pieces of a request and handling them separately, finishing off the entire request after all the pieces are done. When a request queue stalls, normally because its pipe to the I/O thread is full, it is put on the restart list. This list is processed by starting up the queues on it whenever there is some indication that progress might be possible again. Currently, this happens in the driver interrupt routine. Some requests have been finished, so there is likely to be room in the pipe again. This almost doubles throughput when copying data between devices, but made no noticable difference on anything else I tried. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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