From fffca087d587b03d0d0dca2e86bf8e688fbf2c18 Mon Sep 17 00:00:00 2001 From: Francesco Pollicino Date: Tue, 12 Mar 2019 09:59:34 +0100 Subject: [PATCH] block, bfq: save & resume weight on a queue merge/split MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit bfq saves the state of a queue each time a merge occurs, to be able to resume such a state when the queue is associated again with its original process, on a split. Unfortunately bfq does not save & restore also the weight of the queue. If the weight is not correctly resumed when the queue is recycled, then the weight of the recycled queue could differ from the weight of the original queue. This commit adds the missing save & resume of the weight. Tested-by: Holger Hoffstätte Tested-by: Oleksandr Natalenko Signed-off-by: Francesco Pollicino Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe --- block/bfq-iosched.c | 2 ++ block/bfq-iosched.h | 9 +++++++++ 2 files changed, 11 insertions(+) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 37cc8f127cf6..ceb06abd73df 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -1028,6 +1028,7 @@ bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_data *bfqd, else bfq_clear_bfqq_IO_bound(bfqq); + bfqq->entity.new_weight = bic->saved_weight; bfqq->ttime = bic->saved_ttime; bfqq->wr_coeff = bic->saved_wr_coeff; bfqq->wr_start_at_switch_to_srt = bic->saved_wr_start_at_switch_to_srt; @@ -2502,6 +2503,7 @@ static void bfq_bfqq_save_state(struct bfq_queue *bfqq) if (!bic) return; + bic->saved_weight = bfqq->entity.orig_weight; bic->saved_ttime = bfqq->ttime; bic->saved_has_short_ttime = bfq_bfqq_has_short_ttime(bfqq); bic->saved_IO_bound = bfq_bfqq_IO_bound(bfqq); diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h index 67e63c276c7a..60c148728cc5 100644 --- a/block/bfq-iosched.h +++ b/block/bfq-iosched.h @@ -404,6 +404,15 @@ struct bfq_io_cq { */ bool was_in_burst_list; + /* + * Save the weight when a merge occurs, to be able + * to restore it in case of split. If the weight is not + * correctly resumed when the queue is recycled, + * then the weight of the recycled queue could differ + * from the weight of the original queue. + */ + unsigned int saved_weight; + /* * Similar to previous fields: save wr information. */ -- 2.30.2