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Deadline iosched: Reset batch for ordered requests 

The deadline I/O scheduler does not reset the batch count when starting
a new batch at a higher-sectored request.  This means the second and
subsequent batch in the same data direction will never exceed a single
request in size whenever higher-sectored requests are pending.

This patch gives new batches in the same data direction as old ones
their full quota of requests by resetting the batch count.

Signed-off-by: Aaron Carroll <aaronc@gelato.unsw.edu.au>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Aaron Carroll 2007-10-30 10:40:13 +01:00 committed by Jens Axboe
parent 5d1a536621
commit dfb3d72a9a
1 changed files with 3 additions and 3 deletions
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6
block/deadline-iosched.c
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@ -306,12 +306,11 @@ dispatch_writes:
dispatch_find_request:
/*
* we are not running a batch, find best request for selected data_dir
* and start a new batch
*/
if (deadline_check_fifo(dd, data_dir)) {
/* An expired request exists - satisfy it */
dd->batching = 0;
rq = rq_entry_fifo(dd->fifo_list[data_dir].next);
} else if (dd->next_rq[data_dir]) {
/*
* The last req was the same dir and we have a next request in
@ -325,12 +324,13 @@ dispatch_find_request:
* higher-sectored requests. Go back to the lowest sectored
* request (1 way elevator) and start a new batch.
*/
dd->batching = 0;
node = rb_first(&dd->sort_list[data_dir]);
if (node)
rq = rb_entry_rq(node);
}
dd->batching = 0;
dispatch_request:
/*
* rq is the selected appropriate request.