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| author | Keith Busch <kbusch@kernel.org> | 2023-03-20 12:49:26 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-03-20 15:30:03 -0600 |
| commit | 54bdd67d0f88489ac88f7664b56cb7c93799d84d (patch) | |
| tree | 7c0c5780eb49ae1ca5c33b23c32b566c1b4a7c46 /Documentation/ABI/stable | |
| parent | 4cf2c3ab2cdfed71a7f27fe52b4c87877ee79606 (diff) | |
| download | linux-54bdd67d0f88489ac88f7664b56cb7c93799d84d.tar.gz | |
blk-mq: remove hybrid polling
io_uring provides the only way user space can poll completions, and that
always sets BLK_POLL_NOSLEEP. This effectively makes hybrid polling dead
code, so remove it and everything supporting it.
Hybrid polling was effectively killed off with 9650b453a3d4b1, "block:
ignore RWF_HIPRI hint for sync dio", but still potentially reachable
through io_uring until d729cf9acb93119, "io_uring: don't sleep when
polling for I/O", but hybrid polling probably should not have been
reachable through that async interface from the beginning.
Fixes: 9650b453a3d4 ("block: ignore RWF_HIPRI hint for sync dio")
Fixes: d729cf9acb93 ("io_uring: don't sleep when polling for I/O")
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20230320194926.3353144-1-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'Documentation/ABI/stable')
| -rw-r--r-- | Documentation/ABI/stable/sysfs-block | 15 |
1 files changed, 4 insertions, 11 deletions
diff --git a/Documentation/ABI/stable/sysfs-block b/Documentation/ABI/stable/sysfs-block index 282de3680367d..c57e5b7cb5326 100644 --- a/Documentation/ABI/stable/sysfs-block +++ b/Documentation/ABI/stable/sysfs-block @@ -336,18 +336,11 @@ What: /sys/block/<disk>/queue/io_poll_delay Date: November 2016 Contact: linux-block@vger.kernel.org Description: - [RW] If polling is enabled, this controls what kind of polling - will be performed. It defaults to -1, which is classic polling. + [RW] This was used to control what kind of polling will be + performed. It is now fixed to -1, which is classic polling. In this mode, the CPU will repeatedly ask for completions - without giving up any time. If set to 0, a hybrid polling mode - is used, where the kernel will attempt to make an educated guess - at when the IO will complete. Based on this guess, the kernel - will put the process issuing IO to sleep for an amount of time, - before entering a classic poll loop. This mode might be a little - slower than pure classic polling, but it will be more efficient. - If set to a value larger than 0, the kernel will put the process - issuing IO to sleep for this amount of microseconds before - entering classic polling. + without giving up any time. + <deprecated> What: /sys/block/<disk>/queue/io_timeout |