Deadline iosched: Reset batch for ordered requests (dfb3d72a) · Commits · 戴 / test

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>

block/deadline-iosched.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -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.

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