Date: Wed, 29 Apr 2015 13:15:32 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Waiman Long <waiman.long@hp.com>
Cc: Jason Low <jason.low2@hp.com>, Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel@vger.kernel.org,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Oleg Nesterov <oleg@redhat.com>,
        Frederic Weisbecker <fweisbec@gmail.com>, Mel Gorman <mgorman@suse.de>,
        Rik van Riel <riel@redhat.com>,
        Preeti U Murthy <preeti@linux.vnet.ibm.com>,
        Mike Galbraith <umgwanakikbuti@gmail.com>,
        Davidlohr Bueso <dave@stgolabs.net>,
        Aswin Chandramouleeswaran <aswin@hp.com>,
        Scott J Norton <scott.norton@hp.com>
Subject: Re: [PATCH v2 1/5] sched, timer: Remove usages of ACCESS_ONCE in
 the scheduler
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On Wed, 29 Apr 2015 13:05:55 -0400
Waiman Long <waiman.long@hp.com> wrote:

> >   		goto no_join;
> > @@ -2107,7 +2107,7 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
> >
> >   static void reset_ptenuma_scan(struct task_struct *p)
> >   {
> > -	ACCESS_ONCE(p->mm->numa_scan_seq)++;
> > +	WRITE_ONCE(p->mm->numa_scan_seq, READ_ONCE(p->mm->numa_scan_seq) + 1);
> >   	p->mm->numa_scan_offset = 0;
> >   }
> >
> >
> 
> Generally, I am for replacing ACCESS_ONCE() with the more descriptive 
> READ_ONCE() and WRITE_ONCE() except the above case where it makes the 
> code harder to read without any real advantage.
> 
> Other than that,
> 
> Acked-by: Waiman Long <Waiman.Long@hp.com>
> 

I agree, but I believe this code needs to be updated anyway. Making it
uglier may encourage that to happen.

-- Steve
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