af5f6e27d5
Currently, the lock_is_read_held variable is bool, so that a reader sets it to true just after lock acquisition and then to false just before lock release. This works in a rough statistical sense, but can result in false negatives just after one of a pair of concurrent readers has released the lock. This approach does have low overhead, but at the expense of the setting to true potentially never leaving the reader's store buffer, thus resulting in an unconditional false negative. This commit therefore converts this variable to atomic_t and makes the reader use atomic_inc() just after acquisition and atomic_dec() just before release. This does increase overhead, but this increase is negligible compared to the 10-microsecond lock hold time. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| 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 | ||
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.