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 2D4774BCAD6; Mon, 6 Jul 2026 09:15:49 +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=1783329356; cv=none; b=h9JjyWrVkp5QSvZRHCNgWWX8qkziuxcsv82pmjZf4jCq1G/+2Srfbl/Om4NvcIrQ4CV+aJbUL/u55vmpB9oTCi86cGdfv2lpCMgJxWz+c7OA1TQ3HFgWGFr0JtAlO02R48PqnochNDtjpDXbfg6ZKAmCQ4X/OStQ+BwqEDr3tRM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783329356; c=relaxed/simple; bh=QJ5HYOo1sZr+RAZDpfHmJKKZulL4cWyqvGndm2DUaJ0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=aC+gp73WWJHQkfzgmbwFs1N5jLHMtzje3feaTTays+hNrgO689zBRW7jPQGfqV6UMJTx4GhfbQhf42NZ9uB0sE854YsntFIhdwebOVAEzzGgxrkd0SWKRHYsOPoirRQhtB1CRc39MnzMAnQdvngdI7wcEOHXgG2qbOwPo9CXWMM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PuHdcLS1; 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="PuHdcLS1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B6B81F000E9; Mon, 6 Jul 2026 09:15:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783329341; bh=bokzjo0yW55RfvluZv8dBD0vpjCIgsPtps5JnOgTFww=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=PuHdcLS1JTZ9/r5Mr4tauz++6saoXfkiZkpk17nVpbDKcJKf9cDmGBG5lRKa/b/cb m5aHsmlaHkT+ptUZkhSvSlQLJ7I1GpFf0JpcIljNfrqqgYpiDBhQjkzQXsateYVWg+ 4FbzPzDDVXQjKSZ4+QTp7H2efjV4RdUOuR66Yb4kMI2VtBUj2/PlFtkJuSJYmjilVs RjSM2dUGGPJG7cvGItYbpQ/80J9wMK/LFMss6b+pi2qO4Q6AkoARLZVCO4kB3OKEej tA48zarkJbc+ndBT2e7reXXpM6FTtuqmG3Iu3b7Frg7nZbVhCMEUpDg4YXVhzR49jd w68UsR7xZn/nw== Message-ID: <8a6f0bc0-5b6d-406d-9d2c-d3861b5c31b5@kernel.org> Date: Mon, 6 Jul 2026 11:15:36 +0200 Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 3/8] mm: add a set_page_section_from_pfn() helper To: Li Zhe , akpm@linux-foundation.org, apopple@nvidia.com, arnd@arndb.de, bp@alien8.de, dave.hansen@linux.intel.com, kees@kernel.org, mingo@redhat.com, rppt@kernel.org, tglx@kernel.org Cc: linux-arch@vger.kernel.org, linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org References: <20260701090553.62691-1-lizhe.67@bytedance.com> <20260701090553.62691-4-lizhe.67@bytedance.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/1/26 11:05, Li Zhe wrote: > Callers that want to update section bits from a PFN currently need to > open-code: > > set_page_section(page, pfn_to_section_nr(pfn)); > > and guard that sequence with #ifdef SECTION_IN_PAGE_FLAGS. > > Add set_page_section_from_pfn() to wrap that update in one place. When > section bits are stored in page flags, the helper derives the section > number from the PFN and updates the page flags. Otherwise it degrades to > a no-op. > > Convert set_page_links() to use the new helper so later ZONE_DEVICE > fast-path patches can also update section bits without open-coding > SECTION_IN_PAGE_FLAGS at each callsite. > > This keeps the PFN-to-section translation local to the configurations > that actually store section bits in struct page flags, and avoids > exposing that detail to generic callers. > > No functional change intended. > > Signed-off-by: Li Zhe > Reviewed-by: Mike Rapoport (Microsoft) > --- > include/linux/mm.h | 19 ++++++++++++++++--- > 1 file changed, 16 insertions(+), 3 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 485df9c2dbdd..f78afa63dd3d 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2541,11 +2541,26 @@ static inline void set_page_section(struct page *page, unsigned long section) > page->flags.f |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT; > } > > +static inline void set_page_section_from_pfn(struct page *page, > + unsigned long pfn) Two tab indent. > +{ > + set_page_section(page, pfn_to_section_nr(pfn)); > +} > + > static inline unsigned long memdesc_section(memdesc_flags_t mdf) > { > return (mdf.f >> SECTIONS_PGSHIFT) & SECTIONS_MASK; > } > #else /* !SECTION_IN_PAGE_FLAGS */ > +static inline void set_page_section(struct page *page, unsigned long section) > +{ > +} Why do we need this? > + > +static inline void set_page_section_from_pfn(struct page *page, > + unsigned long pfn) > +{ > +} Dito. > + > static inline unsigned long memdesc_section(memdesc_flags_t mdf) > { > return 0; > @@ -2768,9 +2783,7 @@ static inline void set_page_links(struct page *page, enum zone_type zone, > { > set_page_zone(page, zone); > set_page_node(page, node); > -#ifdef SECTION_IN_PAGE_FLAGS > - set_page_section(page, pfn_to_section_nr(pfn)); > -#endif > + set_page_section_from_pfn(page, pfn); > } > > /** -- Cheers, David