Commit d1f600fa authored by Paolo Valente's avatar Paolo Valente Committed by Jens Axboe
Browse files

block, bfq: fix switch back from soft-rt weitgh-raising 



A bfq_queue may happen to be deemed as soft real-time while it is
still enjoying interactive weight-raising. If this happens because of
a false positive, then the bfq_queue is likely to loose its soft
real-time status soon. Upon losing such a status, the bfq_queue must
get back its interactive weight-raising, if its interactive period is
not over yet. But this case is not handled. This commit corrects this
error.

Tested-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarPaolo Valente <paolo.valente@linaro.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 7f1995c2

block/bfq-iosched.c

+20 −2
Original line number Diff line number Diff line
@@ -5290,8 +5290,26 @@ bfq_update_io_seektime(struct bfq_data *bfqd, struct bfq_queue *bfqq, 


	if (bfqq->wr_coeff > 1 &&

	    bfqq->wr_cur_max_time == bfqd->bfq_wr_rt_max_time &&

	    BFQQ_TOTALLY_SEEKY(bfqq))

	    BFQQ_TOTALLY_SEEKY(bfqq)) {

		if (time_is_before_jiffies(bfqq->wr_start_at_switch_to_srt +

					   bfq_wr_duration(bfqd))) {

			/*

			 * In soft_rt weight raising with the

			 * interactive-weight-raising period

			 * elapsed (so no switch back to

			 * interactive weight raising).

			 */

			bfq_bfqq_end_wr(bfqq);

		} else { /*

			  * stopping soft_rt weight raising

			  * while still in interactive period,

			  * switch back to interactive weight

			  * raising

			  */

			switch_back_to_interactive_wr(bfqq, bfqd);

			bfqq->entity.prio_changed = 1;

		}

	}

}



static void bfq_update_has_short_ttime(struct bfq_data *bfqd,