915d4ad383
Use atomic64_try_cmpxchg() instead of atomic64_cmpxchg() in __update_gt_cputime(). The x86 CMPXCHG instruction returns success in ZF flag, so this change saves a compare after cmpxchg() (and related move instruction in front of cmpxchg()). Also, atomic64_try_cmpxchg() implicitly assigns old *ptr value to "old" when cmpxchg() fails. There is no need to re-read the value in the loop. No functional change intended. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20230116165337.5810-1-ubizjak@gmail.com
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.