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Date:   Thu, 3 Aug 2023 15:01:00 +0300
From:   "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To:     Ryan Roberts <ryan.roberts@arm.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Matthew Wilcox <willy@infradead.org>,
        Yin Fengwei <fengwei.yin@intel.com>,
        David Hildenbrand <david@redhat.com>,
        Yu Zhao <yuzhao@google.com>, Yang Shi <shy828301@gmail.com>,
        "Huang, Ying" <ying.huang@intel.com>, Zi Yan <ziy@nvidia.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Alexander Gordeev <agordeev@linux.ibm.com>,
        Gerald Schaefer <gerald.schaefer@linux.ibm.com>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v4 0/3] Optimize large folio interaction with deferred
 split
Message-ID: <20230803120100.2glxdc4yf7sjn7h5@box.shutemov.name>
References: <20230727141837.3386072-1-ryan.roberts@arm.com>
 <b308fbb3-73a1-f8b4-3b08-ed5da044b2a9@arm.com>
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On Wed, Aug 02, 2023 at 05:42:23PM +0100, Ryan Roberts wrote:
>  - avoid the split lock contention by using mmu gather (suggested by Kirill)

[Offlist]

So, my idea is to embed struct deferred_split into struct mmu_gather and
make zap path to use it instead of per-node/per-memcg deferred_split. This
would avoid lock contention. If the list is not empty after zap, move the
to the per-node/per-memcg deferred_split.

But it is only relevant if we see lock contention.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov