linux-kernel - Re: [PATCH v2 3/3] mm/memory-failure: simplify __page_handle

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Message-ID: <CACw3F50ZKCGaQrOEgoH6g8YCcK7Fs=tEiywZhqUzqkkeV_SsVg@mail.gmail.com>
Date: Mon, 22 Dec 2025 15:13:00 -0800
From: Jiaqi Yan <jiaqiyan@...gle.com>
To: Matthew Wilcox <willy@...radead.org>
Cc: jackmanb@...gle.com, hannes@...xchg.org, linmiaohe@...wei.com, 
	ziy@...dia.com, harry.yoo@...cle.com, nao.horiguchi@...il.com, 
	david@...hat.com, lorenzo.stoakes@...cle.com, william.roche@...cle.com, 
	tony.luck@...el.com, wangkefeng.wang@...wei.com, jane.chu@...cle.com, 
	akpm@...ux-foundation.org, osalvador@...e.de, muchun.song@...ux.dev, 
	rientjes@...gle.com, duenwen@...gle.com, jthoughton@...gle.com, 
	linux-mm@...ck.org, linux-kernel@...r.kernel.org, Liam.Howlett@...cle.com, 
	vbabka@...e.cz, rppt@...nel.org, surenb@...gle.com, mhocko@...e.com
Subject: Re: [PATCH v2 3/3] mm/memory-failure: simplify __page_handle_poison

On Mon, Dec 22, 2025 at 2:12 PM Matthew Wilcox <willy@...radead.org> wrote:
>
> On Fri, Dec 19, 2025 at 06:33:46PM +0000, Jiaqi Yan wrote:
> > Now that no HWPoison page will be given away to buddy allocator
> > at the end of dissolve_free_hugetlb_folio, there is no need to
> > drain_all_pages and take_page_off_buddy anymore, so remove them.
>
> What if we discover a hardware error in a page which is currently
> in the buddy system?  Why don't we need to remove that page from the
> buddy system?

Thanks for your comment.

memory_failure() explicitly handles is_free_buddy_page() case and is
removing from buddy allocator with take_page_off_buddy() directly.

However, when soft_offline_page() handles free page with
page_handle_poison(), removing from buddy allocator is missing with
this patch.

I will fix this in v3. One way is to split hugepage_or_freepage and
only take_page_off_buddy() for non-huge free page.