On Mon, Jul 22, 2024 at 5:09 AM Baoquan He <bhe@xxxxxxxxxx> wrote: > > On 07/19/24 at 12:38pm, Uros Bizjak wrote: > > Use atomic_try_cmpxchg_acquire(*ptr, &old, new) instead of > > atomic_cmpxchg_acquire(*ptr, old, new) == old in kexec_trylock(). > > x86 CMPXCHG instruction returns success in ZF flag, so > > this change saves a compare after cmpxchg. > > Seems it can simplify code even though on non-x86 arch, should we > replace atomic_try_cmpxchg_acquire() with atomic_try_cmpxchg_acquire() > in all similar places? Yes, the change is beneficial also for non-x86 architectures, please see analysis at thread [1]. I've been looking through the kernel sources for these places for quite some time, and I believe I have changed most of the places. The change is relatively straightforward, and immediately results in a better code. [1] https://lore.kernel.org/lkml/871qwgmqws.fsf@xxxxxxxxxxxxxxxxxx/ > > For this one, > > Acked-by: Baoquan He <bhe@xxxxxxxxxx> Thanks, Uros. _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
