diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/bfq-iosched.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 2a84294b0525..a3f59d3065b3 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -5860,7 +5860,17 @@ static void bfq_completed_request(struct bfq_queue *bfqq, struct bfq_data *bfqd) 1UL<<(BFQ_RATE_SHIFT - 10)) bfq_update_rate_reset(bfqd, NULL); bfqd->last_completion = now_ns; - bfqd->last_completed_rq_bfqq = bfqq; + /* + * Shared queues are likely to receive I/O at a high + * rate. This may deceptively let them be considered as wakers + * of other queues. But a false waker will unjustly steal + * bandwidth to its supposedly woken queue. So considering + * also shared queues in the waking mechanism may cause more + * control troubles than throughput benefits. Then do not set + * last_completed_rq_bfqq to bfqq if bfqq is a shared queue. + */ + if (!bfq_bfqq_coop(bfqq)) + bfqd->last_completed_rq_bfqq = bfqq; /* * If we are waiting to discover whether the request pattern |