forked from Minki/linux
mainlining shenanigans
9ca9fb24d5
Currently we do two extra spin lock/unlock pairs to add a poll/apoll request to the cancellation hash table and remove it from there. On the submission side we often already hold ->uring_lock and tw completion is likely to hold it as well. Add a second cancellation hash table protected by ->uring_lock. In concerns for latency because of a need to have the mutex locked on the completion side, use the new table only in following cases: 1) IORING_SETUP_SINGLE_ISSUER: only one task grabs uring_lock, so there is little to no contention and so the main tw hander will almost always end up grabbing it before calling callbacks. 2) IORING_SETUP_SQPOLL: same as with single issuer, only one task is a major user of ->uring_lock. 3) apoll: we normally grab the lock on the completion side anyway to execute the request, so it's free. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/1bbad9c78c454b7b92f100bbf46730a37df7194f.1655371007.git.asml.silence@gmail.com Reviewed-by: Hao Xu <howeyxu@tencent.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.