From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-90.mta0.migadu.com [91.218.175.90]) (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 EF6852989B5 for ; Sat, 10 Oct 2026 08:37:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.90 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791621483; cv=none; b=DtVlybmxZyY3bPspIeEYQyp6ImIdC4bfHtX0pAB/114HAdLKYC88L6eR7F9u1Cf2dIRlv5yoQyNqt+ebW/vDKbXW6nXy7PvyYZrRUi/acHF7mC7FujSQyg9Ia6ERdkpRbQGiwv1e8OmUgJbuOZfJ696Uzm0afuN0zzEup2tMT0s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791621483; c=relaxed/simple; bh=+PRO4n3F+OyGen9J5HY+faBhF6ZEkZwsHa88ihF2mE0=; h=Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc: Message-Id:References:To; b=NXCIVccCe1Ct1anW0dcnXO7WWEIxd30DW7KCJ0QMw3psPtwx7UenUMjr5epC6X7yvag308gTlBj4pZ6qXskTMNqU7jwTjouIk3aICQXyXPkwfrp5xEd4qPkLBTpeKXw7PXOJeYXa7Oc3vcJWlRCspHB7zz0tVWdK1m3nCSUz1wA= 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=QBA7G/g8; arc=none smtp.client-ip=91.218.175.90 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="QBA7G/g8" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=+PRO4n3F+OyGen9J5HY+faBhF6ZEkZwsHa88ihF2mE0=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1791621472; v=1; x=1792226272; b=QBA7G/g8sj2aYCkQ/RrD4TBG3enwlM+9wuP8ceggjgLRHL+yuZGvT8v9XkQ09Vou5kbLFuPe eb7prH1fGSWih6UfTArfuOJevMeCkymOpNIFhdYM/D22cAkgVDsG1mr+XZJM5OVPmiPGxFvWHoj 1zfdabbJKhtVYlFfGxS7mzpM= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 15e719b1ad28d653; Sat, 10 Oct 2026 08:37:51 +0000 X-Mizu-Trace-ID: 15e719b1ad28d653 X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset=us-ascii Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3901.100.1.1.12\)) Subject: Re: [PATCH v4 3/6] mm/sparse-vmemmap: drop Device DAX-specific population path From: Muchun Song In-Reply-To: <20261010075755.83339-4-songmuchun@bytedance.com> Date: Sat, 10 Oct 2026 16:37:35 +0800 Cc: Madhavan Srinivasan , Mike Rapoport , Andrew Morton , David Hildenbrand , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Ritesh Harjani , Shrikanth Hegde , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Qi Zheng , Lance Yang , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Content-Transfer-Encoding: quoted-printable Message-Id: <42099448-FB7B-4885-9DE3-DBB6C96B88FF@linux.dev> References: <20261010075755.83339-1-songmuchun@bytedance.com> <20261010075755.83339-4-songmuchun@bytedance.com> To: Muchun Song X-Mailer: Apple Mail (2.3901.100.1.1.12) > On Oct 10, 2026, at 15:57, Muchun Song = wrote: >=20 > The common vmemmap path selects the shared page for optimized mappings > itself, so Device DAX no longer needs = vmemmap_populate_compound_pages() > to find a shared tail page and pass its backing PFN through the = generic > population helpers. >=20 > Remove the Device DAX-specific population path and let section memmap > population always use vmemmap_populate(). The powerpc retains an > architecture-specific compound-page implementation, so select it = directly > from radix__vmemmap_populate() for optimizable sections. Regarding the issue mentioned by Sashiko [1], it does exist, but it was not introduced by this series. I have already fixed it in another series [2], but it has not been merged yet. [1] = https://sashiko.dev/#/patchset/20261010075755.83339-1-songmuchun%40bytedan= ce.com?part=3D3 [2] = https://lore.kernel.org/all/20260924025035.1265035-1-songmuchun@bytedance.= com/ Thanks.=