block, bfq: save & resume weight on a queue merge/split

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 <holger@applied-asynchrony.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Francesco Pollicino <fra.fra.800@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 2 insertions, 0 deletions

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);