From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3E9203955E8 for ; Thu, 13 Aug 2026 09:01:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786611669; cv=none; b=LLT81H0oX0JMn/8ydMBY5kZtyXi1mFSX5esRo74hWZK+KOQR4m2zcD1MDbgKKD0PA9K8IeJ93de2mFLi9QgEAaTmtI47m1zdHUARbkNV6LCgo4jVe14Pu0WCR4LaaattpeehIwzPXXlDtKbyvVb/6wLc5Gg0Cko5+4Dua0R1ocs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786611669; c=relaxed/simple; bh=Fl3cibuRBSrLdMRPjC4E/gY98cTK30Tqac7pEspmIOQ=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=WkakALMpURk4+l6H0pdvGOWK2FNnNqRgrVq2/gstg0q12idGnuzgpYNyDCIJv1ID9cXHBGb3aJXZZRhmyb2ZPpYGPRQpDwskDth1jFihLXGahJTjsM2Ma4GZvupTmTPTQ6LkeQkFn/AWq1PzWgwtE3DfSQPy44fYzEMM9gCq/4c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iAkJaMtM; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iAkJaMtM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA2D41F00A3A; Thu, 13 Aug 2026 09:01:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786611667; bh=Y9O+191m0uBz3Oh/7L7UAfh/wJKAqqGNUbdnCQ8c2N0=; h=Date:Subject:From:To:Cc:References:In-Reply-To; b=iAkJaMtMOdiOmhfeJui4hvi0zurvyPRCg1hxCp/mj5yKnXOowW3KbXg1EIIs6Rfo5 /cyddz345GqfbiEoa+YwJrtUJijtEL+C25/oxoDXovtLm7gddr7lfFShGDqolpxFiZ lUUrctDej5iVevEUL7f+NrKeRvAPduUTvZA7tp7GGRF9tL/Dpwy6HV0DOwb4PULNuR P+UbouheLbm6EeXb0bxLy+aJaQ4tcDyz9qUMoJj4HIvLVpdOE8tr7mXImZBeFGIdVN eZ4IEq/7pulooMyUhs7DcvYt/perkmR3S/fif3r3GfRLcTkYO33H9QXmW8Y+4awuXr 2bOVXfjf4f/Uw== Message-ID: Date: Thu, 13 Aug 2026 11:01:02 +0200 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v9 06/15] kpageflags: Use is_page_hwpoison() to set KPF_HWPOISON From: "David Hildenbrand (Arm)" To: "Matthew Wilcox (Oracle)" , Andrew Morton , Jane Chu , linux-mm@kvack.org Cc: Muchun Song , Oscar Salvador , Miaohe Lin , Naoya Horiguchi , Jan Kara , linux-fsdevel@vger.kernel.org, Christian Brauner , Jiaqi Yan , "Gregory Price (Meta)" References: <20260805210557.1118966-1-willy@infradead.org> <20260805210557.1118966-7-willy@infradead.org> <3e609c64-a393-4667-be74-6cb2bbdcb717@kernel.org> Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/13/26 09:25, David Hildenbrand (Arm) wrote: > On 8/5/26 23:05, Matthew Wilcox (Oracle) wrote: >> Instead of knowing how hugetlb handles hwpoison, just ask >> is_page_hwpoison(). This gives us the flexibility to change how hwpoison >> is handled without updating this function in the future. >> >> Signed-off-by: Matthew Wilcox (Oracle) >> Reviewed-by: Jane Chu >> Reviewed-by: Gregory Price (Meta) >> --- >> fs/proc/page.c | 8 ++------ >> 1 file changed, 2 insertions(+), 6 deletions(-) >> >> diff --git a/fs/proc/page.c b/fs/proc/page.c >> index 7d9387143435..323e4c049f69 100644 >> --- a/fs/proc/page.c >> +++ b/fs/proc/page.c >> @@ -233,12 +233,8 @@ u64 stable_page_flags(const struct page *page) >> u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable); >> u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked); >> >> -#ifdef CONFIG_MEMORY_FAILURE >> - if (u & (1 << KPF_HUGE)) >> - u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison); >> - else >> - u |= kpf_copy_bit(ps.page_snapshot.flags.f, KPF_HWPOISON, PG_hwpoison); >> -#endif >> + if (is_page_hwpoison(page)) >> + u |= 1 << KPF_HWPOISON; I also just realized, that other users in this function now use BIT_ULL. > > snapshot_page() takes a snapshot of the folio and the page. If you look at > "page", you start going to the live version again. > If we really cannot use the snapshot_page, one alternative to avoid using "page" after actually snapshotting it would be: diff --git a/fs/proc/page.c b/fs/proc/page.c index 260772b20bd99..f2fc0917f0b6c 100644 --- a/fs/proc/page.c +++ b/fs/proc/page.c @@ -223,12 +223,8 @@ u64 stable_page_flags(const struct page *page) u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable); u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked); -#ifdef CONFIG_MEMORY_FAILURE - if (u & BIT_ULL(KPF_HUGE)) - u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison); - else - u |= kpf_copy_bit(ps.page_snapshot.flags.f, KPF_HWPOISON, PG_hwpoison); -#endif + if (ps.flags & PAGE_SNAPSHOT_HWPOISON) + u |= BIT_ULL(KPF_HWPOISON); u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved); u |= kpf_copy_bit(k, KPF_OWNER_2, PG_owner_2); diff --git a/include/linux/mm.h b/include/linux/mm.h index 29f13cc6b52a2..7e14e58b98c38 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -5496,6 +5496,7 @@ static inline bool page_pool_page_is_pp(const struct page *page) #define PAGE_SNAPSHOT_FAITHFUL (1 << 0) #define PAGE_SNAPSHOT_PG_BUDDY (1 << 1) #define PAGE_SNAPSHOT_PG_IDLE (1 << 2) +#define PAGE_SNAPSHOT_HWPOISON (1 << 3) struct page_snapshot { struct folio folio_snapshot; diff --git a/mm/util.c b/mm/util.c index bf0513d1d3d08..06195d0801130 100644 --- a/mm/util.c +++ b/mm/util.c @@ -1294,6 +1294,8 @@ static void set_ps_flags(struct page_snapshot *ps, const struct folio *folio, ps->flags |= PAGE_SNAPSHOT_PG_BUDDY; else if (page_count(page) == 0 && is_free_buddy_page(page)) ps->flags |= PAGE_SNAPSHOT_PG_BUDDY; + if (is_page_hwpoison(page)) + ps->flags |= PAGE_SNAPSHOT_HWPOISON; if (folio_test_idle(folio)) ps->flags |= PAGE_SNAPSHOT_PG_IDLE; (I'm starting to hate all these different hwpoison helpers) -- Cheers, David