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>
(cherry picked from commit 2ec5a5c48373d4bc2f0699f86507a65bf0b9df35)
(cherry picked from commit 0750db9767232fc2e4850868e526f4b02ecfb247)
(cherry picked from commit 8676f43249bbb0478a8b18bd87703da59902dbfd)
(cherry picked from commit df655d250f253a2f8a6792569108f30a04b7b894)
(cherry picked from commit d76168c1c3805a2c948e7ff60c8eb341e2ff0013)
(cherry picked from commit f213ae4e575f8ed67ae065fe80d06dc957f0b068)
(cherry picked from commit eb1ff3ab6d66081fbaf007c6cfc1a5e841719c0c)
The return value is ioprio * BFQ_WEIGHT_CONVERSION_COEFF or 0.
What we want is ioprio or 0.
Correct this by changing the calculation.
Signed-off-by: Yahu Gao <gaoyahu19@gmail.com>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20220107065859.25689-1-gaoyahu19@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
(cherry picked from commit bcd2be763252f3a4d5fc4d6008d4d96c601ee74b)
(cherry picked from commit 81806db867a17e49d37b1d556dd39f4da5227f56)
(cherry picked from commit aed9dbfda208b30130c64bac55570e2f89084d2b)
(cherry picked from commit 7158b54afec4b986d52cc646a5dffc30eac6dc19)
(cherry picked from commit fb4f80f773e0fc89f372c7afda9c8e9794849f67)
(cherry picked from commit 5ad409c78ed2bfca202490fa13f0a93c49f21382)
