aleph/lkl_linux
1
0
Fork 0
mirror of https://github.com/lkl/linux.git synced 2025-12-19 08:03:01 +09:00
Code Issues Packages Projects Releases Wiki Activity

block, bfq: always inject I/O of queues blocked by wakers

Browse Source 
Suppose that I/O dispatch is plugged, to wait for new I/O for the
in-service bfq-queue, say bfqq.  Suppose then that there is a further
bfq_queue woken by bfqq, and that this woken queue has pending I/O. A
woken queue does not steal bandwidth from bfqq, because it remains
soon without I/O if bfqq is not served. So there is virtually no risk
of loss of bandwidth for bfqq if this woken queue has I/O dispatched
while bfqq is waiting for new I/O. In contrast, this extra I/O
injection boosts throughput. This commit performs this extra
injection.

Tested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Link: https://lore.kernel.org/r/20210304174627.161-2-paolo.valente@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Paolo Valente
2021-03-04 18:46:22 +01:00
committed by Jens Axboe
parent 9cf1adc6d3
commit 2ec5a5c483
2 changed files with 35 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
block/bfq-wf2q.c
View File

@@ -1706,4 +1706,12 @@ void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq)
if (bfqq->wr_coeff > 1)
bfqd->wr_busy_queues++;
/* Move bfqq to the head of the woken list of its waker */
if (!hlist_unhashed(&bfqq->woken_list_node) &&
&bfqq->woken_list_node != bfqq->waker_bfqq->woken_list.first) {
hlist_del_init(&bfqq->woken_list_node);
hlist_add_head(&bfqq->woken_list_node,
&bfqq->waker_bfqq->woken_list);
}
}