From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932496AbdJVVrQ (ORCPT ); Sun, 22 Oct 2017 17:47:16 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:45553 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932352AbdJVVnS (ORCPT ); Sun, 22 Oct 2017 17:43:18 -0400 Message-Id: <20171022214052.903003886@linutronix.de> User-Agent: quilt/0.63-1 Date: Sun, 22 Oct 2017 23:39:59 +0200 From: Anna-Maria Gleixner To: LKML Cc: Thomas Gleixner , Peter Zijlstra , Ingo Molnar , keescook@chromium.org, Christoph Hellwig , John Stultz Subject: [PATCH v2 21/37] hrtimer: Make remote enqueue decision less restrictive References: <20171022213938.940451689@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=hrtimer--check-target-fix.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current decision whether a timer can be queued on a remote CPU checks for timer->expiry <= remote_cpu_base.expires_next. This is too restrictive because a timer with the same expiry time as an existing timer will be enqueued on right-hand size of the existing timer inside the rbtree, i.e. behind the first expiring timer. So its safe to allow enqueuing timers with the same expiry time as the first expiring timer on a remote CPU base. Signed-off-by: Anna-Maria Gleixner --- kernel/time/hrtimer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -168,7 +168,7 @@ hrtimer_check_target(struct hrtimer *tim ktime_t expires; expires = ktime_sub(hrtimer_get_expires(timer), new_base->offset); - return expires <= new_base->cpu_base->expires_next; + return expires < new_base->cpu_base->expires_next; } #ifdef CONFIG_NO_HZ_COMMON