diff options
| author | Stephen Bates <sbates@raithlin.com> | 2016-09-13 20:23:15 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2016-09-14 16:41:21 +0200 |
| commit | 6e219353afa1f67f453141f7462b01708ebf5574 (patch) | |
| tree | d09924891e887e970be9a18442bebc40d2ad64ee /block/blk-core.c | |
| parent | nbd: allow block mq to deal with timeouts (diff) | |
| download | linux-6e219353afa1f67f453141f7462b01708ebf5574.tar.xz linux-6e219353afa1f67f453141f7462b01708ebf5574.zip | |
block: add poll_considered statistic
In order to help determine the effectiveness of polling in a running
system it is usful to determine the ratio of how often the poll
function is called vs how often the completion is checked. For this
reason we add a poll_considered variable and add it to the sysfs entry
for io_poll.
Signed-off-by: Stephen Bates <sbates@raithlin.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-core.c')
| -rw-r--r-- | block/blk-core.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 34ff8088eebe..14d7c0740dc0 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -3307,19 +3307,23 @@ bool blk_poll(struct request_queue *q, blk_qc_t cookie) { struct blk_plug *plug; long state; + unsigned int queue_num; + struct blk_mq_hw_ctx *hctx; if (!q->mq_ops || !q->mq_ops->poll || !blk_qc_t_valid(cookie) || !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) return false; + queue_num = blk_qc_t_to_queue_num(cookie); + hctx = q->queue_hw_ctx[queue_num]; + hctx->poll_considered++; + plug = current->plug; if (plug) blk_flush_plug_list(plug, false); state = current->state; while (!need_resched()) { - unsigned int queue_num = blk_qc_t_to_queue_num(cookie); - struct blk_mq_hw_ctx *hctx = q->queue_hw_ctx[queue_num]; int ret; hctx->poll_invoked++; |