106397376c
Current code supposes that it is enough to provide forward progress by just waking up one wait queue after one completion batch is done. Unfortunately this way isn't enough, cause waiter can be added to wait queue just after it is woken up. Follows one example(64 depth, wake_batch is 8) 1) all 64 tags are active 2) in each wait queue, there is only one single waiter 3) each time one completion batch(8 completions) wakes up just one waiter in each wait queue, then immediately one new sleeper is added to this wait queue 4) after 64 completions, 8 waiters are wakeup, and there are still 8 waiters in each wait queue 5) after another 8 active tags are completed, only one waiter can be wakeup, and the other 7 can't be waken up anymore. Turns out it isn't easy to fix this problem, so simply wakeup enough waiters for single batch. Cc: Kemeng Shi <shikemeng@huaweicloud.com> Cc: Chengming Zhou <zhouchengming@bytedance.com> Cc: Jan Kara <jack@suse.cz> Signed-off-by: David Jeffery <djeffery@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de> Reviewed-by: Keith Busch <kbusch@kernel.org> Link: https://lore.kernel.org/r/20230721095715.232728-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.