Date: Tue, 14 Apr 2015 19:59:06 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Jason Low <jason.low2@hp.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        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>,
        Mike Galbraith <umgwanakikbuti@gmail.com>,
        Frederic Weisbecker <fweisbec@gmail.com>, Mel Gorman <mgorman@suse.de>,
        Preeti U Murthy <preeti@linux.vnet.ibm.com>, hideaki.kimura@hp.com,
        Aswin Chandramouleeswaran <aswin@hp.com>,
        Scott J Norton <scott.norton@hp.com>
Subject: Re: [PATCH 1/3] sched, timer: Remove usages of ACCESS_ONCE in the
 scheduler
Message-ID: <20150414195906.3adc89d9@gandalf.local.home>
In-Reply-To: <1429052986-9420-2-git-send-email-jason.low2@hp.com>
References: <1429052986-9420-1-git-send-email-jason.low2@hp.com>
	<1429052986-9420-2-git-send-email-jason.low2@hp.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 714
Lines: 23

On Tue, 14 Apr 2015 16:09:44 -0700
Jason Low <jason.low2@hp.com> wrote:


> @@ -2088,7 +2088,7 @@ 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);

Is the READ_ONCE() inside the WRITE_ONCE() really necessary?

>  	p->mm->numa_scan_offset = 0;
>  }
>  

-- Steve
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/