From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-40.mta1.migadu.com [95.215.58.40]) (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 70AAC342CB0 for ; Wed, 30 Sep 2026 10:02:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.40 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790762561; cv=none; b=L3NJuUe7KG24s7peLBHsPtKeCIY1cEuwD3jcXpVouRgt6lO1OmyRqo6jX0oxKU/2lGQBE5hS7VFHuzHQ+q776cPWvfdWTr0t5xNPO2TulqWVzOZy4EdKLlq4yvgEs+HH0FGusqX993vUa5uCu5lvG1egrOlbNXQNzMtQf4Z5WRY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790762561; c=relaxed/simple; bh=6qRsSUfuBnTMx2Y9L6KCbkAYKGnB+pDv2tFE4p6k81k=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=UZfIKaqquBAiJm1jbQefoFqWYkHhF2VKN79ELpnfAN3MsRIsWa96sEtufJ5TsWDin8hN59COXCvNlYVMHgI0kwt5dgEol4VVeNMNj2BDQ4NO8gRo/WWbDMLplqtdhR/KJmjCWMTAvasO8n7382vsY2X4l/ZJNkh7xnr8qr+IWvA= 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=HWh+cF4X; arc=none smtp.client-ip=95.215.58.40 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="HWh+cF4X" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=6qRsSUfuBnTMx2Y9L6KCbkAYKGnB+pDv2tFE4p6k81k=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790762557; v=1; x=1791367357; b=HWh+cF4XUnRtzQm0It3amwBWG8qCSbFI7QAeMYEKlfO+p4LRI6Ea5ZQISrIm5wJxFLBmhFZG QwUMz/c1caYinhyh9cELzBCVUpo+DJa6uJxaDMVHSmq0UrGkgozLn1szy6faWgfdcGsuLDeC6wV hAuJQdkRpF4wLnBqX71XYd4s= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 702ad52dc12a4244; Wed, 30 Sep 2026 10:02:36 +0000 X-Mizu-Trace-ID: 702ad52dc12a4244 X-Migadu-Flow: FLOW_OUT From: Lance Yang To: songmuchun@bytedance.com Cc: maddy@linux.ibm.com, rppt@kernel.org, akpm@linux-foundation.org, david@kernel.org, mpe@ellerman.id.au, npiggin@gmail.com, chleroy@kernel.org, ritesh.list@gmail.com, sshegde@linux.ibm.com, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, surenb@google.com, mhocko@suse.com, qi.zheng@linux.dev, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, muchun.song@linux.dev, Lance Yang Subject: Re: [PATCH v3 2/6] mm/sparse-vmemmap: support device DAX in common vmemmap path Date: Wed, 30 Sep 2026 18:02:26 +0800 Message-ID: <20260930100226.23688-1-lance.yang@linux.dev> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20260929053231.66085-3-songmuchun@bytedance.com> References: <20260929053231.66085-3-songmuchun@bytedance.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On Tue, Sep 29, 2026 at 01:32:27PM +0800, Muchun Song wrote: >The common vmemmap population path cannot yet handle optimized Device DAX >mappings on its own. It uses pfn_to_zone() to find the shared tail page, >but Device DAX populates its vmemmap at runtime before the ZONE_DEVICE span >is initialized. > >Teach the common path to use device_zone() for runtime optimized vmemmap >population while retaining pfn_to_zone() for early boot. This allows the >same path to support both early boot mappings and Device DAX. > >The backing PFN supplied by the Device DAX-specific population path is no >longer used, allowing the redundant lookup and population code to be >removed later. > >Signed-off-by: Muchun Song >Acked-by: Qi Zheng >--- Nothing jumped out at me, feel free to add: Reviewed-by: Lance Yang