From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-133.mta0.migadu.com [91.218.175.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 161924AA595 for ; Tue, 8 Sep 2026 09:29:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788859783; cv=none; b=HE/gwLLs1ClezXFIA2gDR7isAMNfitF08ilK2ccfJgoiHwuFR6jhF8aNlbUYRn+34au8K6t2pzinXwFQLwLV+5wokhLdEX168nbIBkgF2441V3/xXNCAS7WO98WVuecFfX4P2ZeamfLIncrVHW0n0Yf094PnUVoR4BFz7YnguTs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788859783; c=relaxed/simple; bh=15IOOyKa+ijGmMxg7kwu9CI1MNJx0YkgAkPki5J/TZI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=uRpBU5cs0p1JjN/WnaEMcnQcYsdRCEKqA9rtL8NqJt9COBBZWUBF1glk6qTzaNuLvt8SmgFgR6vZm3vlqlciwHy2IiKmwoaM1i7dlxtb2TfcKKEW8GaDpNqDcB7mSD4ghf2u03lJcLOmbcJSGcdqnEmoTGU5KYhfjlo/zuLhuI4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=NT4ngglp; arc=none smtp.client-ip=91.218.175.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="NT4ngglp" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=15IOOyKa+ijGmMxg7kwu9CI1MNJx0YkgAkPki5J/TZI=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1788859780; v=1; x=1789464580; b=NT4ngglpu+P1qCAwMpvi5skJVqMX/UTGMoDC8wwv+T+PdUQBVVmjF2FUVhdYdbO9TwQ0CvzN VImV7aNtVlKFs6JVQGKU8UHxprvBNk0VJgiTliDg1qEsPoHzunKUJDVQVQimHC01jnyUp+VmXla n3/GnnhU8bFZ68YQHQVjMam0= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id c1b4dc536328070e; Tue, 08 Sep 2026 09:29:39 +0000 X-Mizu-Trace-ID: c1b4dc536328070e X-Migadu-Flow: FLOW_OUT Message-ID: Date: Tue, 8 Sep 2026 17:29:34 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 11/11] Documentation/mm: update DAX vmemmap deduplication docs To: Muchun Song , Andrew Morton , David Hildenbrand , Oscar Salvador , Madhavan Srinivasan , Michael Ellerman , Jonathan Corbet Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-doc@vger.kernel.org, Muchun Song , Lorenzo Stoakes , Mike Rapoport , Nicholas Piggin , Christophe Leroy , Randy Dunlap References: <20260908030335.96549-1-songmuchun@bytedance.com> <20260908030335.96549-12-songmuchun@bytedance.com> From: Qi Zheng In-Reply-To: <20260908030335.96549-12-songmuchun@bytedance.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 9/8/26 11:03 AM, Muchun Song wrote: > Device DAX now uses the common per-zone shared tail page for vmemmap > deduplication. The old documentation still described a DAX-specific > layout with a separately populated tail vmemmap page and half the HugeTLB > savings. > > Update the generic and powerpc documentation to describe the shared layout. > In the powerpc document, keep the radix and 64K-specific details, drop the > duplicated 4K PUD arithmetic, and replace the repeated device-dax diagrams > with a single parameterized PMD/PUD diagram. > > Signed-off-by: Muchun Song > --- > v2: > - Clarify the commit message to state that the 4K PUD arithmetic is > intentionally dropped reported by Sashiko. > --- > Documentation/arch/powerpc/vmemmap_dedup.rst | 90 ++++---------------- > Documentation/mm/vmemmap_dedup.rst | 32 +------ > 2 files changed, 21 insertions(+), 101 deletions(-) Acked-by: Qi Zheng Thanks, Qi