Re: [PATCH] Revert "mm/page_alloc: protect pcp->batch accesses with ACCESS_ONCE"

[Hekuang]

hi

å 2016/3/30 18:38, Mel Gorman åé:
> On Wed, Mar 30, 2016 at 10:22:07AM +0000, He Kuang wrote:
> > This reverts commit 998d39cb236fe464af86a3492a24d2f67ee1efc2.
> >
> > When local irq is disabled, a percpu variable does not change, so we can
> > remove the access macros and let the compiler optimize the code safely.
> batch can be changed from other contexts. Why is this safe?
I've mistakenly thought that per_cpu variable can only be accessed by 
that cpu.
Thanks.