Pavel Begunkov
e516c3fc6c
When enlisting a bio into ->free_list_irq we protect the list by
disabling irqs. It's likely they're already disabled and performance of
local_irq_{save,restore}() is decent, but it's not zero cost.
Let's only use the irq cache when when we're serving a hard irq, which
allows to remove local_irq_{save,restore}(), and fall back to bio_free()
in all left cases.
Profiles indicate that the bio_put() cost is reduced by ~3.5 times
(1.76% -> 0.49%), and total throughput of a CPU bound benchmark improve
by around 1% (t/io_uring with high QD and several drives).
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/36d207540b7046c653cc16e5ff08fe7234b19f81.1707314970.git.asml.silence@gmail.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 Restructured Text 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.