From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757606AbcJXM1G (ORCPT ); Mon, 24 Oct 2016 08:27:06 -0400 Received: from merlin.infradead.org ([205.233.59.134]:55732 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757528AbcJXM0v (ORCPT ); Mon, 24 Oct 2016 08:26:51 -0400 Date: Mon, 24 Oct 2016 14:26:39 +0200 From: Peter Zijlstra To: Jiri Olsa Cc: Michael Ellerman , Michael Neuling , Paul Mackerras , Jiri Olsa , lkml , Ingo Molnar , Alexander Shishkin , Jan Stancek Subject: Re: [PATCHv2] perf powerpc: Don't call perf_event_disable from atomic context Message-ID: <20161024122639.GN3102@twins.programming.kicks-ass.net> References: <1474466134-21823-1-git-send-email-jolsa@kernel.org> <20160923163747.GE5012@twins.programming.kicks-ass.net> <20161003132932.GA28947@krava> <20161003134740.GC3117@twins.programming.kicks-ass.net> <87shsc4tzm.fsf@concordia.ellerman.id.au> <20161005080921.GB6467@krava> <20161005195338.GB28329@krava> <20161006072415.GF3568@worktop.programming.kicks-ass.net> <20161006123301.GA13093@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161006123301.GA13093@krava> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 06, 2016 at 02:33:01PM +0200, Jiri Olsa wrote: > diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c > index aec9a1b1d25b..4d3bcbbf626a 100644 > --- a/arch/powerpc/kernel/hw_breakpoint.c > +++ b/arch/powerpc/kernel/hw_breakpoint.c > @@ -275,7 +275,7 @@ int __kprobes hw_breakpoint_handler(struct die_args *args) > if (!stepped) { > WARN(1, "Unable to handle hardware breakpoint. Breakpoint at " > "0x%lx will be disabled.", info->address); > - perf_event_disable(bp); > + perf_event_disable_inatomic(bp); > goto out; > } > /* > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h > index 5c5362584aba..c794fd84a595 100644 > --- a/include/linux/perf_event.h > +++ b/include/linux/perf_event.h > @@ -1248,6 +1248,7 @@ extern u64 perf_swevent_set_period(struct perf_event *event); > extern void perf_event_enable(struct perf_event *event); > extern void perf_event_disable(struct perf_event *event); > extern void perf_event_disable_local(struct perf_event *event); > +extern void perf_event_disable_inatomic(struct perf_event *event); > extern void perf_event_task_tick(void); > #else /* !CONFIG_PERF_EVENTS: */ > static inline void * > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 7c0d263f6bc5..3d650ccf4def 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -1960,6 +1960,13 @@ void perf_event_disable(struct perf_event *event) > } > EXPORT_SYMBOL_GPL(perf_event_disable); > > +void perf_event_disable_inatomic(struct perf_event *event) > +{ > + event->pending_kill = POLL_HUP; > + event->pending_disable = 1; > + irq_work_queue(&event->pending); > +} > + > static void perf_set_shadow_time(struct perf_event *event, > struct perf_event_context *ctx, > u64 tstamp) > @@ -7074,9 +7081,7 @@ static int __perf_event_overflow(struct perf_event *event, > event->pending_kill = POLL_IN; > if (events && atomic_dec_and_test(&event->event_limit)) { > ret = 1; > - event->pending_kill = POLL_HUP; > - event->pending_disable = 1; > - irq_work_queue(&event->pending); > + perf_event_disable_inatomic(event); > } > > event->overflow_handler(event, data, regs); I'm a wee bit confused on the event->pending_kill assignment in that helper. AFAICT that's not actually used in the PPC case, and if for some reason, pending_wakeup gets set, do we want to deliver a HUP? The old code didn't do that.