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 23CEB3B3C14; Tue, 18 Aug 2026 17:09:59 +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=1787073001; cv=none; b=Wq9AAq3e+3lnqXYV9o4ozVX9yH4OvZr3Yj92mLeCWSiInysWW8t0To7SZlxs9GL62r81CZ1BUqvhm6SFRY8VnZDzy5qow9SWb6fBDd+DH1qziBJO2vKP2pbWJBLTxiP0xfVo3u1gGUbU+/hoVCPPgrrcsI4iLhB4rZR5d2gwq2c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787073001; c=relaxed/simple; bh=Wu6aFJR5A0U4c4P3xpoIqH0gdFwUFovMFUDheFf0RRo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=S3gfHDFhuQYkbZnWu4yLVwKHa8VU+exgborja6BYwlWFHdYcOLIczXWsSSFz60z6s4Eot5htzmIasacZCtjx03OlkKA49JcMzDLlBo6dUS3vMjEiTAU1FgoYJjgDC8RzS00uuOPMvqOPNVZaubh8s93axaYa+xeHcN/6N0Bjvmg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=i9oH+HrR; 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="i9oH+HrR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 997F61F000E9; Tue, 18 Aug 2026 17:09:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787072999; bh=mxdbgQVht/54cchjqYkheAlWAnzQEAqcDdYfsPmVs6E=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=i9oH+HrR4ZkLLZwsxqREA+oADHZDxEtQsuGvE9vgVhHZrZa+QiBg88qjS4Jh5PUFb AsYtfq4SFgQbxkW5PvPpKO5mQtvQkoPT29zghABG8bxxfmh73hKMBSSZtHUX3KbVQH VbXPEbLHVj3CpB5gbtnKsbxG9MAHICIBv7Dxq48BEtRoM7tyXSABhPpSVBh0lVB+wk HIQxrymbMoC9g7cJW+OtUdbKllpcnD4RoC51TDYfIbzYGWt2JV+RH2Sl4AaNKk2//D 5l14a4blYijmHZKxIXd797sgk9FXxIyrUH6T42zMqU9LTX6wYhrCYGAtm6MTGNMi+q E/6tHgGNSf54Q== Message-ID: <7e40cdfe-67d2-4ddf-a048-f33b2d590371@kernel.org> Date: Tue, 18 Aug 2026 19:09:48 +0200 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 01/57] mm: add pte_folio() To: Kiryl Shutsemau , akpm@linux-foundation.org, ljs@kernel.org, nico.pache@linux.dev Cc: baolin.wang@linux.alibaba.com, baohua@kernel.org, dev.jain@arm.com, hughd@google.com, lance.yang@linux.dev, liam@infradead.org, mhocko@suse.com, rppt@kernel.org, ryan.roberts@arm.com, shuah@kernel.org, surenb@google.com, usama.arif@linux.dev, vbabka@kernel.org, ziy@nvidia.com, usama.anjum@arm.com, agordeev@linux.ibm.com, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, kas@kernel.org, jannh@google.com, willy@infradead.org, pfalcato@suse.de, rostedt@goodmis.org, mhiramat@kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org References: <20260816224609.308019-1-kirill@shutemov.name> <20260816224609.308019-2-kirill@shutemov.name> 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 8/17/26 00:45, Kiryl Shutsemau wrote: > From: "Kiryl Shutsemau (Meta)" > > Callers that want the folio behind a present PTE spell it out as > page_folio(pte_page(pte)). > > Add pte_folio() as the folio companion to pte_page(), and convert the > callers in fs/proc/task_mmu.c and mm/hugetlb.c. > > Preparation for the anonymous collapse engine, which reads the folio > behind a PTE in several places. [...] > > +/** > + * pte_folio - Return the folio mapped by a present PTE. > + * @pte: A present page table entry. > + * > + * The folio companion to pte_page(); only meaningful for a present PTE > + * that maps a struct-page-backed folio. > + * > + * Return: The folio containing the page @pte maps. > + */ > +static inline struct folio *pte_folio(pte_t pte) > +{ > + return page_folio(pte_page(pte)); > +} There is a reason why most code doesn't need that: because they should be using vm_normal_page() / vm_normal_folio(), or need the exact page and handle special ptes differently (see gup.c that uses pte_page()). And other code that uses pte_page() doesn't really operate on folios AFAIKs. That's also why you are only touching hugetlb code here. IOW, there must be a pretty good reason for us to add a non-hugetlb helper when that looks like a good fit for common code when it's really only hugetlb that does weird things (and doesn't need the exact page!). If we really *need* this helper, we should spell out clearly that it is very likely the wrong thing to use outside hugetlb code. -- Cheers, David