mirror of
https://github.com/torvalds/linux.git
synced 2024-12-02 17:11:33 +00:00
A mirror of the official Linux kernel repository just in case
291d47ccad
This just does the "if the architecture does efficient unaligned handling, start the memcmp using 'unsigned long' accesses", since Nikolay Borisov found a load that cares. This is basically the minimal patch, and limited to architectures that are known to not have slow unaligned handling. We've had the stupid byte-at-a-time version forever, and nobody has ever even noticed before, so let's keep the fix minimal. A potential further improvement would be to align one of the sources in order to at least minimize unaligned cases, but the only real case of bigger memcmp() users seems to be the FIDEDUPERANGE ioctl(). As David Sterba says, the dedupe ioctl is typically called on ranges spanning many pages so the common case will all be page-aligned anyway. All the relevant architectures select HAVE_EFFICIENT_UNALIGNED_ACCESS, so I'm not going to worry about the combination of a very rare use-case and a rare architecture until somebody actually hits it. Particularly since Nikolay also tested the more complex patch with extra alignment handling code, and it only added overhead. Link: https://lore.kernel.org/lkml/20210721135926.602840-1-nborisov@suse.com/ Reported-by: Nikolay Borisov <nborisov@suse.com> Cc: David Sterba <dsterba@suse.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|---|---|---|
| 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.