From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753692AbcJDQtq (ORCPT ); Tue, 4 Oct 2016 12:49:46 -0400 Received: from mail-wm0-f51.google.com ([74.125.82.51]:37873 "EHLO mail-wm0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751479AbcJDQtp (ORCPT ); Tue, 4 Oct 2016 12:49:45 -0400 MIME-Version: 1.0 In-Reply-To: <87lgyer5x4.fsf@ashishki-desk.ger.corp.intel.com> References: <20160923112726.5890-1-alexander.shishkin@linux.intel.com> <20160923112726.5890-7-alexander.shishkin@linux.intel.com> <87lgyer5x4.fsf@ashishki-desk.ger.corp.intel.com> From: Mathieu Poirier Date: Tue, 4 Oct 2016 10:49:43 -0600 Message-ID: Subject: Re: [RFC PATCH 6/6] perf: Disable IRQs in address filter sync path To: Alexander Shishkin Cc: Peter Zijlstra , Ingo Molnar , "linux-kernel@vger.kernel.org" , Vince Weaver , Stephane Eranian , Arnaldo Carvalho de Melo , Thomas Gleixner , Andi Kleen Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 26 September 2016 at 10:18, Alexander Shishkin wrote: > Alexander Shishkin writes: > >> If PMU callbacks are executed in hardirq context, the address filter >> sync code needs to disable interrupts when taking its spinlock to be >> consistent with the rest of its users. This may happen if the PMU is >> used in AUX sampling. > > Hi Mathieu, > > I've been meaning to CC you on this series and forgot. My concern was > that on PMUs that run PMIs in hardirq context this patch should be > required already now. Is this the case for you? At this time cross triggers haven't been implemented and as such, PMIs aren't an issue. On the flip side I can see the value of your code when we get around to do the implementation. Mathieu > >> >> Signed-off-by: Alexander Shishkin >> --- >> kernel/events/core.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/kernel/events/core.c b/kernel/events/core.c >> index f6582df1c9..047c495c94 100644 >> --- a/kernel/events/core.c >> +++ b/kernel/events/core.c >> @@ -2568,16 +2568,17 @@ static int perf_event_stop(struct perf_event *event, int restart) >> void perf_event_addr_filters_sync(struct perf_event *event) >> { >> struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); >> + unsigned long flags; >> >> if (!has_addr_filter(event)) >> return; >> >> - raw_spin_lock(&ifh->lock); >> + raw_spin_lock_irqsave(&ifh->lock, flags); >> if (event->addr_filters_gen != event->hw.addr_filters_gen) { >> event->pmu->addr_filters_sync(event); >> event->hw.addr_filters_gen = event->addr_filters_gen; >> } >> - raw_spin_unlock(&ifh->lock); >> + raw_spin_unlock_irqrestore(&ifh->lock, flags); >> } >> EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync); >> >> -- >> 2.9.3