linux-kernel - Re: [PATCH v6 00/15] mm: folio_zero

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Message-ID: <aMRnarU3w_XykRHG@x1>
Date: Fri, 12 Sep 2025 15:33:14 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Ankur Arora <ankur.a.arora@...cle.com>
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org, x86@...nel.org,
	akpm@...ux-foundation.org, david@...hat.com, bp@...en8.de,
	dave.hansen@...ux.intel.com, hpa@...or.com, mingo@...hat.com,
	mjguzik@...il.com, luto@...nel.org, peterz@...radead.org,
	namhyung@...nel.org, tglx@...utronix.de, willy@...radead.org,
	raghavendra.kt@....com, boris.ostrovsky@...cle.com,
	konrad.wilk@...cle.com
Subject: Re: [PATCH v6 00/15] mm: folio_zero_user: clear contiguous pages

On Tue, Sep 02, 2025 at 01:08:01AM -0700, Ankur Arora wrote:
> This series adds clearing of contiguous page ranges for hugepages,
> improving on the current page-at-a-time approach in two ways:
> 
>  - amortizes the per-page setup cost over a larger extent
> 
>  - when using string instructions, exposes the real region size
>    to the processor.
> 
> A processor could use a knowledge of the extent to optimize the
> clearing.  AMD Zen uarchs, as an example, elide allocation of
> cachelines for regions larger than L3-size.
> 
> Demand faulting a 64GB region shows performance improvements:
> 
>  $ perf bench mem map -p $pg-sz -f demand -s 64GB -l 5

So, can I go ahead and pull the tools/perf/ bits into perf-tools-next,
Namhyung already reviewed it, the rest can go thru the relevant
channels, ok?

- Arnaldo