From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934706AbcCJB4r (ORCPT ); Wed, 9 Mar 2016 20:56:47 -0500 Received: from smtp2.provo.novell.com ([137.65.250.81]:35371 "EHLO smtp2.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751429AbcCJB4i (ORCPT ); Wed, 9 Mar 2016 20:56:38 -0500 From: Davidlohr Bueso To: mingo@kernel.org Cc: peterz@infradead.org, dave@stgolabs.net, linux-kernel@vger.kernel.org, Davidlohr Bueso Subject: [PATCH 2/2] kernel/smp: Use make csd_lock_wait be smp_cond_acquire Date: Wed, 9 Mar 2016 17:55:36 -0800 Message-Id: <1457574936-19065-3-git-send-email-dbueso@suse.de> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1457574936-19065-1-git-send-email-dbueso@suse.de> References: <1457574936-19065-1-git-send-email-dbueso@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Davidlohr Bueso We can micro-optimize this call and mildly relax the barrier requirements by relying on ctrl + rmb, keeping the acquire semantics. In addition, this is pretty much the now standard for busy-waiting under such restraints. Signed-off-by: Davidlohr Bueso --- kernel/smp.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/smp.c b/kernel/smp.c index c91e00178f8f..74165443c240 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -107,8 +107,7 @@ void __init call_function_init(void) */ static __always_inline void csd_lock_wait(struct call_single_data *csd) { - while (smp_load_acquire(&csd->flags) & CSD_FLAG_LOCK) - cpu_relax(); + smp_cond_acquire(!(csd->flags & CSD_FLAG_LOCK)); } static __always_inline void csd_lock(struct call_single_data *csd) -- 2.1.4