From 54bdd67d0f88489ac88f7664b56cb7c93799d84d Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Mon, 20 Mar 2023 12:49:26 -0700 Subject: 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 Link: https://lore.kernel.org/r/20230320194926.3353144-1-kbusch@meta.com Signed-off-by: Jens Axboe --- Documentation/ABI/stable/sysfs-block | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) (limited to 'Documentation/ABI/stable') 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//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. + What: /sys/block//queue/io_timeout -- cgit