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authorFrancesco Pollicino <fra.fra.800@gmail.com>2019-03-12 09:59:34 +0100
committerJens Axboe <axboe@kernel.dk>2019-04-01 08:15:40 -0600
commitfffca087d587b03d0d0dca2e86bf8e688fbf2c18 (patch)
tree2ea5b0643ecf6adf4971033b21deaa9cbae63f03
parent1e66413c4f68e2a61a210e4f5ff5df7a2ab86a5b (diff)
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>
-rw-r--r--block/bfq-iosched.c2
-rw-r--r--block/bfq-iosched.h9
2 files changed, 11 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);
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
@@ -405,6 +405,15 @@ 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.
*/
unsigned long saved_wr_coeff;