Re: [PATCH v4 4/7] x86/tlb: fall back to flush all when meet a THPlarge page

From: Peter Zijlstra
Date: Thu May 10 2012 - 05:42:02 EST


On Thu, 2012-05-10 at 13:00 +0800, Alex Shi wrote:
> We don't need to flush large pages by PAGE_SIZE step, that just waste
> time. and actually, large page don't need 'invlpg' optimizing according
> to our macro benchmark. So, just flush whole TLB is enough for them.
>
> The following result is tested on a 2CPU * 4cores * 2HT NHM EP machine,
> with THP 'always' setting.

What does it do when you disable THP? That has_large_page() thing is a
massive amount of pointer chasing..
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