Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754219Ab3FOMqq (ORCPT ); Sat, 15 Jun 2013 08:46:46 -0400 Received: from mail-we0-f177.google.com ([74.125.82.177]:50456 "EHLO mail-we0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753922Ab3FOMqp (ORCPT ); Sat, 15 Jun 2013 08:46:45 -0400 Date: Sat, 15 Jun 2013 14:46:41 +0200 From: Frederic Weisbecker To: Oleg Nesterov Cc: Vince Weaver , linux-kernel@vger.kernel.org, Peter Zijlstra , Paul Mackerras , Ingo Molnar , Arnaldo Carvalho de Melo , trinity@vger.kernel.org, Jiri Olsa Subject: Re: [PATCH 2/2] hw_breakpoint: Use cpu_possible_mask in {reserve,release}_bp_slot() Message-ID: <20130615124639.GA1965@somewhere.redhat.com> References: <20130601182057.GA4861@redhat.com> <20130601182139.GC4861@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130601182139.GC4861@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 966 Lines: 25 On Sat, Jun 01, 2013 at 08:21:39PM +0200, Oleg Nesterov wrote: > fetch_bp_busy_slots() and toggle_bp_slot() use for_each_online_cpu(), > this is obviously wrong wrt cpu_up() or cpu_down(), we can over/under > account the per-cpu numbers. > > For example: > > # echo 0 >> /sys/devices/system/cpu/cpu1/online > # perf record -e mem:0x10 -p 1 & > # echo 1 >> /sys/devices/system/cpu/cpu1/online > # perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10 -C1 -a & > # taskset -p 0x2 1 > > triggers the same WARN_ONCE("Can't find any breakpoint slot") in > arch_install_hw_breakpoint(). > > Signed-off-by: Oleg Nesterov > Cc: Acked-by: Frederic Weisbecker -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/