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author | Nitesh Shetty <nj.shetty@samsung.com> | 2018-02-13 21:18:12 +0530 |
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committer | Jens Axboe <axboe@kernel.dk> | 2018-02-13 09:12:04 -0700 |
commit | 67b4110f8c8d16e588d7730db8e8b01b32c1bd8b (patch) | |
tree | b8564dcbfef53bae1b43777ff84e90abb9d61b72 /block/blk-mq.c | |
parent | 178e834c47b0d01352c48730235aae69898fbc02 (diff) | |
download | op-kernel-dev-67b4110f8c8d16e588d7730db8e8b01b32c1bd8b.zip op-kernel-dev-67b4110f8c8d16e588d7730db8e8b01b32c1bd8b.tar.gz |
blk: optimization for classic polling
This removes the dependency on interrupts to wake up task. Set task
state as TASK_RUNNING, if need_resched() returns true,
while polling for IO completion.
Earlier, polling task used to sleep, relying on interrupt to wake it up.
This made some IO take very long when interrupt-coalescing is enabled in
NVMe.
Reference:
http://lists.infradead.org/pipermail/linux-nvme/2018-February/015435.html
Changes since v2->v3:
-using __set_current_state() instead of set_current_state()
Changes since v1->v2:
-setting task state once in blk_poll, instead of multiple
callers.
Signed-off-by: Nitesh Shetty <nj.shetty@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-mq.c')
-rw-r--r-- | block/blk-mq.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index df93102..3574927 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3164,6 +3164,7 @@ static bool __blk_mq_poll(struct blk_mq_hw_ctx *hctx, struct request *rq) cpu_relax(); } + __set_current_state(TASK_RUNNING); return false; } |