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authorKeith Busch <kbusch@kernel.org>2023-03-20 12:49:26 -0700
committerJens Axboe <axboe@kernel.dk>2023-03-20 15:30:03 -0600
commit54bdd67d0f88489ac88f7664b56cb7c93799d84d (patch)
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parent4cf2c3ab2cdfed71a7f27fe52b4c87877ee79606 (diff)
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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-block15
1 files changed, 4 insertions, 11 deletions
diff --git a/Documentation/ABI/stable/sysfs-block b/Documentation/ABI/stable/sysfs-block
index 282de3680367..c57e5b7cb532 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