From: Matthew Wilcox <willy@infradead.org>
To: Gorbunov Ivan <gorbunov.ivan@h-partners.com>
Cc: david@kernel.org, Liam.Howlett@oracle.com,
akpm@linux-foundation.org, apopple@nvidia.com,
baolin.wang@linux.alibaba.com, gladyshev.ilya1@h-partners.com,
harry.yoo@oracle.com, kirill@shutemov.name,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
lorenzo.stoakes@oracle.com, mhocko@suse.com,
muchun.song@linux.dev, rppt@kernel.org, surenb@google.com,
torvalds@linuxfoundation.org, vbabka@suse.cz, yuzhao@google.com,
ziy@nvidia.com, artem.kuzin@huawei.com
Subject: Re: [PATCH v2 2/2] mm: implement page refcount locking via dedicated bit
Date: Thu, 23 Apr 2026 19:24:55 +0100 [thread overview]
Message-ID: <aepj9_v_1dYJ_tRu@casper.infradead.org> (raw)
In-Reply-To: <9936cc799ac8b637ee58ae3bf6ec0e5eeb5306e9.1776350895.git.gorbunov.ivan@h-partners.com>
On Mon, Apr 20, 2026 at 08:01:19AM +0000, Gorbunov Ivan wrote:
> The current atomic-based page refcount implementation treats zero
> counter as dead and requires a compare-and-swap loop in folio_try_get()
> to prevent incrementing a dead refcount. This CAS loop acts as a
> serialization point and can become a significant bottleneck during
> high-frequency file read operations.
If the file read is high-frequency, then for the page refcount to be
the bottleneck, they must be small reads? Have you looked at this
patch?
https://lore.kernel.org/all/20251017141536.577466-1-kirill@shutemov.name/
next prev parent reply other threads:[~2026-04-23 18:25 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-20 8:01 [PATCH v2 0/2] mm: improve folio refcount scalability Gorbunov Ivan
2026-04-20 8:01 ` [PATCH v2 1/2] mm: drop page refcount zero state semantics Gorbunov Ivan
2026-04-23 18:07 ` Bjorn Helgaas
2026-04-23 19:32 ` Zi Yan
2026-04-20 8:01 ` [PATCH v2 2/2] mm: implement page refcount locking via dedicated bit Gorbunov Ivan
2026-04-23 18:24 ` Matthew Wilcox [this message]
2026-04-23 18:31 ` Linus Torvalds
2026-04-23 19:20 ` David Hildenbrand (Arm)
2026-04-23 19:37 ` Zi Yan
2026-04-20 10:07 ` [syzbot ci] Re: mm: improve folio refcount scalability syzbot ci
2026-04-20 12:29 ` Gorbunov Ivan
2026-04-20 13:21 ` syzbot ci
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