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authorPaolo Valente <paolo.valente@linaro.org>2019-01-29 14:06:29 +0300
committerJens Axboe <axboe@kernel.dk>2019-01-31 22:50:23 +0300
commit73d58118498b14e4d2f2391105459b997b586ddc (patch)
tree71e72676425a3eaa6e6ebe582ce27994d1eafbf2 /block/bfq-wf2q.c
parent03e565e4204c6cf8687d995de5cafd0341503b4e (diff)
downloadlinux-73d58118498b14e4d2f2391105459b997b586ddc.tar.xz
block, bfq: consider also ioprio classes in symmetry detection
In asymmetric scenarios, i.e., when some bfq_queue or bfq_group needs to be guaranteed a different bandwidth than other bfq_queues or bfq_groups, these service guaranteed can be provided only by plugging I/O dispatch, completely or partially, when the queue in service remains temporarily empty. A case where asymmetry is particularly strong is when some active bfq_queues belong to a higher-priority class than some other active bfq_queues. Unfortunately, this important case is not considered at all in the code for detecting asymmetric scenarios. This commit adds the missing logic. Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/bfq-wf2q.c')
-rw-r--r--block/bfq-wf2q.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c
index 72adbbe975d5..ce37d709a34f 100644
--- a/block/bfq-wf2q.c
+++ b/block/bfq-wf2q.c
@@ -44,6 +44,12 @@ static unsigned int bfq_class_idx(struct bfq_entity *entity)
BFQ_DEFAULT_GRP_CLASS - 1;
}
+unsigned int bfq_tot_busy_queues(struct bfq_data *bfqd)
+{
+ return bfqd->busy_queues[0] + bfqd->busy_queues[1] +
+ bfqd->busy_queues[2];
+}
+
static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd,
bool expiration);
@@ -1513,7 +1519,7 @@ struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd)
struct bfq_sched_data *sd;
struct bfq_queue *bfqq;
- if (bfqd->busy_queues == 0)
+ if (bfq_tot_busy_queues(bfqd) == 0)
return NULL;
/*
@@ -1665,7 +1671,7 @@ void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq,
bfq_clear_bfqq_busy(bfqq);
- bfqd->busy_queues--;
+ bfqd->busy_queues[bfqq->ioprio_class - 1]--;
if (!bfqq->dispatched)
bfq_weights_tree_remove(bfqd, bfqq);
@@ -1688,7 +1694,7 @@ void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq)
bfq_activate_bfqq(bfqd, bfqq);
bfq_mark_bfqq_busy(bfqq);
- bfqd->busy_queues++;
+ bfqd->busy_queues[bfqq->ioprio_class - 1]++;
if (!bfqq->dispatched)
if (bfqq->wr_coeff == 1)