From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH] percpu: make this_cpu_generic_read notrace Date: Fri, 16 Sep 2016 10:53:09 +0100 Message-ID: <20160916095309.GM3380@arm.com> References: <1473497134-27807-1-git-send-email-zhang.chunyan@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from foss.arm.com ([217.140.101.70]:51722 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751754AbcIPJxJ (ORCPT ); Fri, 16 Sep 2016 05:53:09 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-arch-owner@vger.kernel.org List-ID: To: Chunyan Zhang Cc: Arnd Bergmann , Steven Rostedt , linux-arch@vger.kernel.org, "linux-kernel@vger.kernel.org" , Lyra Zhang On Fri, Sep 16, 2016 at 04:42:44PM +0800, Chunyan Zhang wrote: > Hi Will and Steven, > > May I have a review or an acked-by from you on this patch so that Arnd > can pick it up. > > I have tested this patch on arm qemu, I'm sure it can solve the > problem described in commit message. It looks fine to me; we took your equivalent patch for arm64 already, so: Acked-by: Will Deacon Will > On 10 September 2016 at 16:45, Chunyan Zhang wrote: > > When debug preempt or preempt tracer is enabled, preempt_count_add/sub() > > can be traced by function and function graph tracing, and > > preempt_disable/enable() would call preempt_count_add/sub(), so > > we should use preempt_disable/enable_notrace in Ftrace subsystem. > > > > The function this_cpu_read() started being used by function graph tracing > > after the commit 345ddcc882d8 ("ftrace: Have set_ftrace_pid use the > > bitmap like events do"), so it has to use preempt_disable/enable_notrace > > instead now. > > > > Signed-off-by: Chunyan Zhang > > --- > > include/asm-generic/percpu.h | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h > > index 4d9f233..70fefec 100644 > > --- a/include/asm-generic/percpu.h > > +++ b/include/asm-generic/percpu.h > > @@ -108,9 +108,9 @@ do { \ > > #define this_cpu_generic_read(pcp) \ > > ({ \ > > typeof(pcp) __ret; \ > > - preempt_disable(); \ > > + preempt_disable_notrace(); \ > > __ret = *this_cpu_ptr(&(pcp)); \ > > - preempt_enable(); \ > > + preempt_enable_notrace(); \ > > __ret; \ > > }) > > > > -- > > 2.7.4 > > >