mirror of
https://github.com/torvalds/linux
synced 2024-10-01 17:00:41 +00:00
890a0794b3
Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in __acpi_{acquire,release}_global_lock(). x86 CMPXCHG instruction returns success in ZF flag, so this change saves a compare after CMPXCHG (and related MOV instruction in front of CMPXCHG). Also, try_cmpxchg() implicitly assigns old *ptr value to "old" when CMPXCHG fails. There is no need to re-read the value in the loop. Note that the value from *ptr should be read using READ_ONCE() to prevent the compiler from merging, refetching or reordering the read. No functional change intended. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/r/20230116162522.4072-1-ubizjak@gmail.com |
||
---|---|---|
.. | ||
alpha | ||
arc | ||
arm | ||
arm64 | ||
csky | ||
hexagon | ||
ia64 | ||
loongarch | ||
m68k | ||
microblaze | ||
mips | ||
nios2 | ||
openrisc | ||
parisc | ||
powerpc | ||
riscv | ||
s390 | ||
sh | ||
sparc | ||
um | ||
x86 | ||
xtensa | ||
.gitignore | ||
Kconfig |