From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941243AbcJXPt4 (ORCPT ); Mon, 24 Oct 2016 11:49:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42388 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935768AbcJXPty (ORCPT ); Mon, 24 Oct 2016 11:49:54 -0400 Date: Mon, 24 Oct 2016 17:49:49 +0200 From: Jiri Olsa To: Peter Zijlstra 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: <20161024154949.GA31643@krava> 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> <20161024122639.GN3102@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161024122639.GN3102@twins.programming.kicks-ass.net> User-Agent: Mutt/1.7.1 (2016-10-04) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Mon, 24 Oct 2016 15:49:53 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 24, 2016 at 02:26:39PM +0200, Peter Zijlstra wrote: > > > > 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. right, delivering the signal might change what app is expecting, how about attached change.. I still need to test it thanks, jirka --- diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c index 9781c69eae57..58024eecbd9e 100644 --- a/arch/powerpc/kernel/hw_breakpoint.c +++ b/arch/powerpc/kernel/hw_breakpoint.c @@ -275,7 +275,7 @@ int 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, 0); goto out; } /* diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 060d0ede88df..055bc837bfc1 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1257,6 +1257,7 @@ 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, int kill); 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 c6e47e97b33f..04477983945e 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, int kill) +{ + event->pending_kill = kill; + 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, POLL_HUP); } READ_ONCE(event->overflow_handler)(event, data, regs);