From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751409AbdCQVbj (ORCPT ); Fri, 17 Mar 2017 17:31:39 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:52628 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751191AbdCQVbe (ORCPT ); Fri, 17 Mar 2017 17:31:34 -0400 Message-Id: <20170317212351.023273600@infradead.org> User-Agent: quilt/0.63-1 Date: Fri, 17 Mar 2017 22:19:23 +0100 From: Peter Zijlstra To: mingo@kernel.org, tglx@linutronix.de, hpa@zytor.com Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, arjan@linux.intel.com, bp@alien8.de, richard.weinberger@gmail.com, jpoimboe@redhat.com, peterz@infradead.org Subject: [PATCH 5/5] x86,atomic: Use atomic_try_cmpxchg References: <20170317211918.393791494@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=peterz-x86-atomic-try_cmpxchg.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org text data bss dec hex filename 10665111 4530096 843776 16038983 f4bc47 defconfig-build/vmlinux.3 10655703 4530096 843776 16029575 f49787 defconfig-build/vmlinux.4 Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/include/asm/atomic.h | 27 ++++++++---------------- arch/x86/include/asm/atomic64_64.h | 40 ++++++++++++------------------------- 2 files changed, 22 insertions(+), 45 deletions(-) --- a/arch/x86/include/asm/atomic.h +++ b/arch/x86/include/asm/atomic.h @@ -207,16 +207,12 @@ static inline void atomic_##op(int i, at } #define ATOMIC_FETCH_OP(op, c_op) \ -static inline int atomic_fetch_##op(int i, atomic_t *v) \ +static inline int atomic_fetch_##op(int i, atomic_t *v) \ { \ - int old, val = atomic_read(v); \ - for (;;) { \ - old = atomic_cmpxchg(v, val, val c_op i); \ - if (old == val) \ - break; \ - val = old; \ - } \ - return old; \ + int val = atomic_read(v); \ + do { \ + } while (!atomic_try_cmpxchg(v, &val, val c_op i)); \ + return val; \ } #define ATOMIC_OPS(op, c_op) \ @@ -242,16 +238,11 @@ ATOMIC_OPS(xor, ^) */ static __always_inline int __atomic_add_unless(atomic_t *v, int a, int u) { - int c, old; - c = atomic_read(v); - for (;;) { - if (unlikely(c == (u))) + int c = atomic_read(v); + do { + if (unlikely(c == u)) break; - old = atomic_cmpxchg((v), c, c + (a)); - if (likely(old == c)) - break; - c = old; - } + } while (!atomic_try_cmpxchg(v, &c, c + a)); return c; } --- a/arch/x86/include/asm/atomic64_64.h +++ b/arch/x86/include/asm/atomic64_64.h @@ -198,17 +198,12 @@ static inline long atomic64_xchg(atomic6 */ static inline bool atomic64_add_unless(atomic64_t *v, long a, long u) { - long c, old; - c = atomic64_read(v); - for (;;) { - if (unlikely(c == (u))) - break; - old = atomic64_cmpxchg((v), c, c + (a)); - if (likely(old == c)) - break; - c = old; - } - return c != (u); + long c = atomic64_read(v); + do { + if (unlikely(c == u)) + return false; + } while (!atomic64_try_cmpxchg(v, &c, c + a)); + return true; } #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0) @@ -222,17 +217,12 @@ static inline bool atomic64_add_unless(a */ static inline long atomic64_dec_if_positive(atomic64_t *v) { - long c, old, dec; - c = atomic64_read(v); - for (;;) { + long dec, c = atomic64_read(v); + do { dec = c - 1; if (unlikely(dec < 0)) break; - old = atomic64_cmpxchg((v), c, dec); - if (likely(old == c)) - break; - c = old; - } + } while (!atomic64_try_cmpxchg(v, &c, dec)); return dec; } @@ -248,14 +238,10 @@ static inline void atomic64_##op(long i, #define ATOMIC64_FETCH_OP(op, c_op) \ static inline long atomic64_fetch_##op(long i, atomic64_t *v) \ { \ - long old, val = atomic64_read(v); \ - for (;;) { \ - old = atomic64_cmpxchg(v, val, val c_op i); \ - if (old == val) \ - break; \ - val = old; \ - } \ - return old; \ + long val = atomic64_read(v); \ + do { \ + } while (!atomic64_try_cmpxchg(v, &val, val c_op i)); \ + return val; \ } #define ATOMIC64_OPS(op, c_op) \