Vivek Goyal wrote:
This patch changes anticipatory scheduler to use queue scheduling code from elevator layer. One can go back to old as by deselecting CONFIG_IOSCHED_AS_HIER. Even with CONFIG_IOSCHED_AS_HIER=y, with-out any other cgroup created, AS behavior should remain the same as old. o AS is a single queue ioschduler, that means there is one AS queue per group. o common layer code select the queue to dispatch from based on fairness, and then AS code selects the request with-in group. o AS runs reads and writes batches with-in group. So common layer runs timed group queues and with-in group time, AS runs timed batches of reads and writes. o Note: Previously AS write batch length was adjusted synamically whenever a W->R batch data direction took place and when first request from the read batch completed. Now write batch updation takes place when last request from the write batch has finished during W->R transition. o AS runs its own anticipation logic to anticipate on reads. common layer also does the anticipation on the group if think time of the group is with-in slice_idle. o Introduced few debugging messages in AS. Signed-off-by: Nauman Rafique <nauman@xxxxxxxxxx> Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx> -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
