Kernel Source and devicetree for NOTHING Phone(3a) and Phone(3a)Pro
aa43477b04
It's not possible to go forward with the current state of io_uring polling, we need a more straightforward and easier synchronisation. There are a lot of problems with how it is at the moment, including missing events on rewait. The main idea here is to introduce a notion of request ownership while polling, no one but the owner can modify any part but ->poll_refs of struct io_kiocb, that grants us protection against all sorts of races. Main users of such exclusivity are poll task_work handler, so before queueing a tw one should have/acquire ownership, which will be handed off to the tw handler. The other user is __io_arm_poll_handler() do initial poll arming. It starts taking the ownership, so tw handlers won't be run until it's released later in the function after vfs_poll. note: also prevents races in __io_queue_proc(). Poll wake/etc. may not be able to get ownership, then they need to increase the poll refcount and the task_work should notice it and retry if necessary, see io_poll_check_events(). There is also IO_POLL_CANCEL_FLAG flag to notify that we want to kill request. It makes cancellations more reliable, enables double multishot polling, fixes double poll rewait, fixes missing poll events and fixes another bunch of races. Even though it adds some overhead for new refcounting, and there are a couple of nice performance wins: - no req->refs refcounting for poll requests anymore - if the data is already there (once measured for some test to be 1-2% of all apoll requests), it removes it doesn't add atomics and removes spin_lock/unlock pair. - works well with multishots, we don't do remove from queue / add to queue for each new poll event. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/6b652927c77ed9580ea4330ac5612f0e0848c946.1639605189.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| 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.