From: "David Hildenbrand (Red Hat)" <david@kernel.org>
To: Baolin Wang <baolin.wang@linux.alibaba.com>,
akpm@linux-foundation.org, catalin.marinas@arm.com,
will@kernel.org
Cc: lorenzo.stoakes@oracle.com, ryan.roberts@arm.com,
Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org,
surenb@google.com, mhocko@suse.com, riel@surriel.com,
harry.yoo@oracle.com, jannh@google.com, willy@infradead.org,
baohua@kernel.org, linux-mm@kvack.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] support batched checks of the references for large folios
Date: Mon, 1 Dec 2025 17:23:13 +0100 [thread overview]
Message-ID: <341d1aed-13ad-41ee-ad30-487c5baec399@kernel.org> (raw)
In-Reply-To: <cover.1763976541.git.baolin.wang@linux.alibaba.com>
On 11/25/25 01:56, Baolin Wang wrote:
> Currently, folio_referenced_one() always checks the young flag for each PTE
> sequentially, which is inefficient for large folios. This inefficiency is
> especially noticeable when reclaiming clean file-backed large folios, where
> folio_referenced() is observed as a significant performance hotspot.
>
> Moreover, on Arm architecture, which supports contiguous PTEs, there is already
> an optimization to clear the young flags for PTEs within a contiguous range.
> However, this is not sufficient. We can extend this to perform batched operations
> for the entire large folio (which might exceed the contiguous range: CONT_PTE_SIZE).
>
> By supporting batched checking of the young flags and flushing TLB entries,
> I observed a 33% performance improvement in my file-backed folios reclaim tests.
Can you point at the benchmark or briefly explain what it does? What
exactly are we measuring that improves by 33%?
--
Cheers
David
next prev parent reply other threads:[~2025-12-01 16:23 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-25 0:56 Baolin Wang
2025-11-25 0:56 ` [PATCH 1/2] arm64: mm: support batch clearing of the young flag " Baolin Wang
2025-11-25 0:56 ` [PATCH 2/2] mm: rmap: support batched checks of the references " Baolin Wang
2025-11-25 9:29 ` [PATCH 0/2] " Barry Song
2025-11-25 17:38 ` Kairui Song
2025-12-01 16:23 ` David Hildenbrand (Red Hat) [this message]
2025-12-02 5:37 ` Baolin Wang
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