Re: [patch v2 0/3] mm: improve page aging fairness betweenzones/nodes

From: Andrea Arcangeli
Date: Fri Aug 02 2013 - 16:31:36 EST

On Fri, Aug 02, 2013 at 11:37:23AM -0400, Johannes Weiner wrote:
> Changes in version 2:

v2 looks great to me.

zone->alloc_batch -= 1U << order;
3147: d3 e0 shl %cl,%eax
3149: 29 42 54 sub %eax,0x54(%rdx)

gcc builds it as one asm insn too.

Considering we depend on gcc to be optimal and to update ptes in a
single insn (and if it doesn't we'll corrupt memory), keeping it in C
should always provide the update in a single insn.

I believe the error introduced when mulptiple CPUs of the same NUMA
node step on each other is going to be unmeasurable.

ACK the whole series.

Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>

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