From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Christian König <christian.koenig@amd.com>,
Christoph Hellwig <hch@infradead.org>, Zi Yan <ziy@nvidia.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
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Jeffle Xu <jefflexu@linux.alibaba.com>,
Sandeep Dhavale <dhavale@google.com>,
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Chunhai Guo <guochunhai@vivo.com>
Subject: Re: [PATCH v1 00/11] Zero page->private when freeing pages
Date: Mon, 23 Feb 2026 15:14:45 +0100 [thread overview]
Message-ID: <5105764a-8313-45bd-8b91-8c0ea8cdf077@kernel.org> (raw)
In-Reply-To: <cb8d6ee2-fd1d-436a-b934-aff87adf5dcb@amd.com>
On 2/23/26 15:06, Christian König wrote:
> On 2/23/26 14:46, Christoph Hellwig wrote:
>> On Sun, Feb 22, 2026 at 10:26:30PM -0500, Zi Yan wrote:
>>> Hi all,
>>>
>>> Based on a recent discussion with David Hildenbrand on page->private
>>> is not zero when a page is freed[1], this patchset is trying to fix all
>>> users do not zero ->private when freeing a page and add checks to make
>>> sure all freed pages have ->private set to zero. For compound pages,
>>> both head page and tail pages need to have ->private set to zero.
>>
>> Requiring the user to clear a field before freeing is just a way to
>> awkward interface. Don't do that.
>
> Completely agree. This is just asking for trouble.
>
> The cache line(s) backing this struct page are most likely accessed anyway on free/alloc. So I don't see much extra overhead.
I think the question is more around handling non-head pages when freeing
larger orders. But maybe the overhead of zeroing page->private it there
as well in __free_pages_prepare() is tolerable.
I'll note, though, that we already require page->mapping and
page->memcg_data of pages to be zeroed by the caller, so it's not
completely crazy. (see page_expected_state)
--
Cheers,
David
next prev parent reply other threads:[~2026-02-23 14:15 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-23 3:26 [PATCH v1 00/11] Zero page->private when freeing pages Zi Yan
2026-02-23 3:26 ` [PATCH v1 01/11] relay: zero " Zi Yan
2026-02-23 14:45 ` Usama Arif
2026-02-24 0:52 ` Claude review: " Claude Code Review Bot
2026-02-23 3:26 ` [PATCH v1 02/11] mm/slub: " Zi Yan
2026-02-24 0:52 ` Claude review: " Claude Code Review Bot
2026-02-23 3:26 ` [PATCH v1 03/11] drm/ttm: " Zi Yan
2026-02-23 10:43 ` Christian König
2026-02-24 0:52 ` Claude review: " Claude Code Review Bot
2026-02-23 3:26 ` [PATCH v1 04/11] blk-mq: " Zi Yan
2026-02-24 0:52 ` Claude review: " Claude Code Review Bot
2026-02-23 3:26 ` [PATCH v1 05/11] watch_queue: " Zi Yan
2026-02-24 0:52 ` Claude review: " Claude Code Review Bot
2026-02-23 3:26 ` [PATCH v1 06/11] binder: " Zi Yan
2026-02-24 0:52 ` Claude review: " Claude Code Review Bot
2026-02-23 3:26 ` [PATCH v1 07/11] null_blk: " Zi Yan
2026-02-24 0:52 ` Claude review: " Claude Code Review Bot
2026-02-23 3:26 ` [PATCH v1 08/11] percpu: " Zi Yan
2026-02-24 0:52 ` Claude review: " Claude Code Review Bot
2026-02-23 3:26 ` [PATCH v1 09/11] erofs: " Zi Yan
2026-02-24 0:52 ` Claude review: " Claude Code Review Bot
2026-02-23 3:26 ` [PATCH v1 10/11] mm/huge_memory: add page->private check back in __split_folio_to_order() Zi Yan
2026-02-24 0:52 ` Claude review: " Claude Code Review Bot
2026-02-23 3:26 ` [PATCH v1 11/11] mm/page_alloc: check page->private upon page free Zi Yan
2026-02-24 0:52 ` Claude review: " Claude Code Review Bot
2026-02-23 4:28 ` [PATCH v1 00/11] Zero page->private when freeing pages Matthew Wilcox
2026-02-23 9:36 ` David Hildenbrand (Arm)
2026-02-23 8:40 ` [syzbot ci] " syzbot ci
[not found] ` <aZxaIEFZr2NvO2eQ@infradead.org>
2026-02-23 14:00 ` [PATCH v1 00/11] " Zi Yan
[not found] ` <aZxeLmNyKKTrkSzn@infradead.org>
2026-02-23 14:11 ` Zi Yan
2026-02-23 14:06 ` Christian König
2026-02-23 14:14 ` David Hildenbrand (Arm) [this message]
2026-02-23 15:22 ` Christian König
2026-02-23 15:27 ` David Hildenbrand (Arm)
2026-02-24 0:52 ` Claude review: " Claude Code Review Bot
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