Re: [PATCH v2 3/5] locking/arch: Wire up local_try_cmpxchg
From: Peter Zijlstra <peterz@infradead.org>
Date: 2023-04-12 11:35:27
Also in:
linux-alpha, linux-arch, linux-mips, linux-perf-users, lkml, loongarch
On Wed, Apr 05, 2023 at 04:17:08PM +0200, Uros Bizjak wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/powerpc/include/asm/local.h b/arch/powerpc/include/asm/local.h index bc4bd19b7fc2..45492fb5bf22 100644 --- a/arch/powerpc/include/asm/local.h +++ b/arch/powerpc/include/asm/local.h@@ -90,6 +90,17 @@ static __inline__ long local_cmpxchg(local_t *l, long o, long n) return t; } +static __inline__ bool local_try_cmpxchg(local_t *l, long *po, long n) +{ + long o = *po, r; + + r = local_cmpxchg(l, o, n); + if (unlikely(r != o)) + *po = r; + + return likely(r == o); +} +
Why is the ppc one different from the rest? Why can't it use the try_cmpxchg_local() fallback and needs to have it open-coded?