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 4BDF737AA9C; Tue, 18 Aug 2026 17:19:35 +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=1787073576; cv=none; b=n2nnv12B9yi5fmQNjiP8/TiQlvtt3K0nuLrMiJDRmO6GR1kQbZZGeJ7a8vR0IPimBryPIZ84OnSPzUGLIQLkfzZihHm7WU9rhylb/i3+sAjEla3QRiM4EPtGHzcRO+L33RlDaYIecqF/NqQy5gfui5H/rv4yF/ngxoLRUJRF3hs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787073576; c=relaxed/simple; bh=ZY3wAGy4/nk5lRjHgPOiHQQ2qpYgamdxe08qsuCgAuA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=jLOkEjUNkWcHJMsraGZuAtixzqVaZtSz9RWVxec/nYApO+Xmb8VTbNXvoFeCvX4gZwKyX5akLx7AkqXtGxfcCAocgyX4W19NwZeZX8pbjtONRqYQP3J6jxnrJbKvBLa95QNClndzsuNtO9Hxz3iGv/slCKyo1G1Gv4/BnSg2gHA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ixEfGvLA; 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="ixEfGvLA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A005B1F000E9; Tue, 18 Aug 2026 17:19:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787073574; bh=codh8Et1wTA8GwH2SxVdXCDGWvWVotpR40DaZsbuOm8=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=ixEfGvLA08oUut+wZO9gqjF363gehhEiquE+kroGE9Qtisc+xbewQP5ZBEb7gFAOA KbNI7AqSIDYDy9cun29i8iwrhyKyLmIgC0CQ73atPQ//U2VoxL56zmbzmwRKr3L6AL gc/I9cMk5JQdLA5TGLPGXAJcG2ak/cFBKAFKOrfD+etXsYCRI0VMoq4XDZi/AR4nG6 nwrnwZHNE8CA10F+kKtRYjjeNXsIrVMykJ8A5y6wdrNY0xTXpyUHnAzV4835+X9p6I DRU9OMCFfLp5BM18S39jAexljLZ4SNVtabdKrHShQSCRkmYaIcnY96qooYC++7XdNQ jJkS7Qp59oRpA== Message-ID: <712c2aeb-c0fa-40ef-a086-3898ac44fd25@kernel.org> Date: Tue, 18 Aug 2026 19:19:25 +0200 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 3/3] mm/mempolicy: skip zone device folios when queueing folios To: Gregory Price , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, akpm@linux-foundation.org, ljs@kernel.org, ziy@nvidia.com, baolin.wang@linux.alibaba.com, liam@infradead.org, nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, usama.arif@linux.dev, vbabka@kernel.org, jannh@google.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, ying.huang@linux.alibaba.com, apopple@nvidia.com, balbirs@nvidia.com, stable@vger.kernel.org References: <20260817220810.1175596-1-gourry@gourry.net> <20260817220810.1175596-4-gourry@gourry.net> 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 8/18/26 00:08, Gregory Price wrote: > queue_folios_pte_range() already pairs vm_normal_folio() with an > explicit folio_is_zone_device() check before adding folios to the > migration pagelist. > > vm_normal_folio() alone does not reject zone device memory (a present > device-coherent page in a normal VMA is returned as "normal"). > > Mirror the explicit check in queue_folios_pmd() as well. > > queue_folios_pmd() uses pmd_folio() directly and can encounter a present > zone device PMD - e.g. a device-coherent THP. > > This is not filtered by existing checks: > !pmd_present() - only rejects non-present device-private and > migration entries > > vma_migratable() - excludes DAX and VM_PFNMAP. > > The early return also means such a folio is no longer counted in > qp->nr_failed under MPOL_MF_STRICT. This is the same pattern used > by queue_folios_pte_range() (skipping zone device without failing). > > Fixes: a30b48bf1b24 ("mm/migrate_device: implement THP migration of zone device pages") > Cc: stable@vger.kernel.org > Signed-off-by: Gregory Price (Meta) > --- Acked-by: David Hildenbrand (Arm) -- Cheers, David