linux-kernel - Re: [PATCH v4 0/3] Optimize large folio interaction with deferred split

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Date:   Wed, 2 Aug 2023 11:02:40 -0600
From:   Yu Zhao <yuzhao@...gle.com>
To:     Ryan Roberts <ryan.roberts@....com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Matthew Wilcox <willy@...radead.org>,
        Yin Fengwei <fengwei.yin@...el.com>,
        David Hildenbrand <david@...hat.com>,
        Yang Shi <shy828301@...il.com>,
        "Huang, Ying" <ying.huang@...el.com>, Zi Yan <ziy@...dia.com>,
        Nathan Chancellor <nathan@...nel.org>,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        Gerald Schaefer <gerald.schaefer@...ux.ibm.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH v4 0/3] Optimize large folio interaction with deferred split

On Wed, Aug 2, 2023 at 10:42 AM Ryan Roberts <ryan.roberts@....com> wrote:
>
> Hi Andrew,
>
> After discussion about this in Matthew's THP Cabal, we have decided to take a
> different approach with this patch set. Could you therefore remove it from
> mm-unstable, please? Sorry about the noise.
>
> I'm going to try 2 different approaches:
>  - avoid the split lock contention by using mmu gather (suggested by Kirill)
>  - expand the zap pte batching to also cover file folios (as requested by Yu).

Also we didn't have the chance to clarify before Ryan dropped out from
the meeting: I don't think this series is a prerequisite for the other
series ("variable-order, large folios for anonymous memory") at all.
They can move along in parallel: one is specific for anon and the
other (this series) is generic for all types of large folios.