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486ba4d84d
Previously, the `hash` variable was initialized with `-1` and only updated by io_get_next_work() if the current work was hashed. Commit60cf46ae60("io-wq: hash dependent work") changed this to always call io_get_work_hash() even if the work was not hashed. This caused the `hash != -1U` check to always be true, adding some overhead for the `hash->wait` code. This patch fixes the regression by checking the `IO_WQ_WORK_HASHED` flag. Perf diff for a flood of `IORING_OP_NOP` with `IOSQE_ASYNC`: 38.55% -1.57% [kernel.kallsyms] [k] queued_spin_lock_slowpath 6.86% -0.72% [kernel.kallsyms] [k] io_worker_handle_work 0.10% +0.67% [kernel.kallsyms] [k] put_prev_entity 1.96% +0.59% [kernel.kallsyms] [k] io_nop_prep 3.31% -0.51% [kernel.kallsyms] [k] try_to_wake_up 7.18% -0.47% [kernel.kallsyms] [k] io_wq_free_work Fixes:60cf46ae60("io-wq: hash dependent work") Cc: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Max Kellermann <max.kellermann@ionos.com> Link: https://lore.kernel.org/r/20250128133927.3989681-6-max.kellermann@ionos.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.