Re: [PATCH] time/sched_clock: Use raw_read_seqcount_latch()

From: Leo Yan <leo.yan@linaro.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Ahmed S. Darwish" <a.darwish@linutronix.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Will Deacon <will@kernel.org>,
	John Ogness <jogness@linutronix.de>,
	"Sebastian A. Siewior" <bigeasy@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] time/sched_clock: Use raw_read_seqcount_latch()
Date: Thu, 16 Jul 2020 13:22:59 +0800	[thread overview]
Message-ID: <20200716052259.GA4660@leoy-ThinkPad-X240s> (raw)
In-Reply-To: <20200715155850.GL10769@hirez.programming.kicks-ass.net>

Hi Peter, Ahemd,

On Wed, Jul 15, 2020 at 05:58:50PM +0200, Peter Zijlstra wrote:

[...]

> > > diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
> > > index fa3f800d7d76..ea007928d681 100644
> > > --- a/kernel/time/sched_clock.c
> > > +++ b/kernel/time/sched_clock.c
> > > @@ -100,7 +100,7 @@ unsigned long long notrace sched_clock(void)
> > >  	struct clock_read_data *rd;
> > > 
> > >  	do {
> > > -		seq = raw_read_seqcount(&cd.seq);
> > > +		seq = raw_read_seqcount_latch(&cd.seq);
> > 
> > Understand this is doing the same thing with __ktime_get_fast_ns() and
> > I saw Peter acked to make change for this.
> > 
> > Just want to confirm, since this patch introduces conflict with the
> > patch set "arm64: perf: Proper cap_user_time* support" [1], I should
> > rebase the patch set on top of this patch, right?
> 
> Or rebase this patch on top of yours and include it, either way.

Have rebased this patch and included it in the patch set v3 for
"arm64: perf: Proper cap_user_time* support" [1].

Thanks!
Leo

[1] https://lore.kernel.org/linux-arm-kernel/20200716051130.4359-3-leo.yan@linaro.org/T/#u