Messages in this thread | | | Subject | Re: [PATCH] Revert "mm/page_alloc: protect pcp->batch accesses with ACCESS_ONCE" | From | Hekuang <> | Date | Wed, 30 Mar 2016 18:51:12 +0800 |
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hi
在 2016/3/30 18:38, Mel Gorman 写道: > 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.
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