Messages in this thread | | | From | Pranith Kumar <> | Date | Tue, 12 Aug 2014 10:42:45 -0400 | Subject | Re: [PATCH] sched: Remove ACCESS_ONCE() for jiffies |
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On Tue, Aug 12, 2014 at 1:55 AM, Peter Zijlstra <peterz@infradead.org> wrote: > On Mon, Aug 11, 2014 at 06:51:41PM -0400, Pranith Kumar wrote: >> jiffies is declared as a volatile variable. Therefore it is not neccessary to >> use ACCESS_ONCE() while reading it. > > It also doesn't hurt and it documents intent, so I'm inclined to keep > it.
It looks more like an inconsistency. These are the only three places which use ACCESS_ONCE() for jiffies. Also, in doc/memory-barriers.txt, it explicitly states that ACCESS_ONCE(jiffies) is not necessary. I grepped for this usage after reading that document just to make sure and found these three uses.
But yes, there is no harm being done by using ACCESS_ONCE().
-- Pranith
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