Messages in this thread | | | Date | Thu, 4 Feb 2016 01:53:04 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH 4/4] thp: rewrite freeze_page()/unfreeze_page() with generic rmap walkers |
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On Wed, Feb 03, 2016 at 02:43:16PM -0800, Andrew Morton wrote: > On Wed, 3 Feb 2016 07:42:01 -0800 Dave Hansen <dave.hansen@intel.com> wrote: > > > On 02/03/2016 07:14 AM, Kirill A. Shutemov wrote: > > > But the new variant is somewhat slower. Current helpers iterates over > > > VMAs the compound page is mapped to, and then over ptes within this VMA. > > > New helpers iterates over small page, then over VMA the small page > > > mapped to, and only then find relevant pte. > > > > The code simplification here is really attractive. Can you quantify > > what the slowdown is? Is it noticeable, or would it be in the noise > > during all the other stuff that happens under memory pressure? > > yup.
It is not really clear, how to quantify this properly. Let me think more about it.
> And the "more testing is required" is a bit worrisome. Is this > code really ready for getting pounded upon in -next?
By now it survived 5+ hours of fuzzing in 16 VM in parallel. I'll continue with other tests tomorrow.
-- Kirill A. Shutemov
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