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 C8CA75172CA; Tue, 13 Oct 2026 15:31:48 +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=1791905510; cv=none; b=FItMZ/STMXJ6HGi0usZx3hI2jG4Fuvwg6lh99YqymXnOgnvszGUcY0OiS/mfpGk+DNhFXq525xzfwFJXeYK5Fr4v93Ury0UZqtfQoPoTfOGFHNBWEjcAftFQzb4F1AzRFzua3Y29zbSyL4oB4fYuDtbbU1uhZF0EfU4nTvT6Me8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791905510; c=relaxed/simple; bh=gsmrp0uRtNEEBvwP4Q0pKgs8lFscoCBmjiamKhm7z9Q=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ld0+EU1tPi9dmooxaYAPuh3lcqDt2mNRsH6i5omaPNKLlWb8MFq9+D4+QngBtNJYLf4yjWzRQyDjwRwgoQhiSU44OH2iFNlAKZG39cfSvUZvB3ZauxOA1dt3StT2+YX3xZ0q0DsSJ9O9UOpYnlgdcm3ohxF+0d0QjK486RuBFWM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D5BClKMk; 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="D5BClKMk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0ABA81F000FF; Tue, 13 Oct 2026 15:31:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791905508; bh=ABcU0W+nIwCqZSTy0PPdZy1uyj317pAS/O9WDDdnQZw=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=D5BClKMkyjHNOoeNuUKWF6HwQ8es4HwocZa/1vk5hPJxYK0OE2MtOdN0S2gmcH6lC h2bS5ASLQ2jbvKrWro4RUW2U8G5muKxncrLmF+Jou2z0+IhaAxzQhCEY/LrmDDFWT6 M6xKr2R3fPo+unNvnMZSc2FKExJxWD5IMaBvhhbtafRSFGB4ueb89jIBT5sOdDSJZN GDOdloqs53ZQ9vDKS7F/ry5KwOabJqSqdFue4yGsWFChcPdcnrWzVPTjRyPqdUgvoo j9GhCWKrZ4bFEjuUrlQ3XmGuaXcGd+p+mRRvlVf6aiAfRoUGE+Fx6LYN+MBnX0qWdK WFMXQD15T+n7w== Message-ID: <7bf5a2dc-f7be-425b-99e3-75b4546c8e19@kernel.org> Date: Tue, 13 Oct 2026 17:31:13 +0200 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 30/39] mm/vma: introduce vma[_flags]_is_mm_backed() To: "Lorenzo Stoakes (ARM)" , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Jann Horn , Pedro Falcato , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Greg Kroah-Hartman , Dennis Dalessandro , Jason Gunthorpe , Leon Romanovsky , Paul Moore , Stephen Smalley , Jaroslav Kysela , Takashi Iwai , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kiryl Shutsemau , Doug Gilbert , "James E.J. Bottomley" , "Martin K. Petersen" , Simona Vetter , Helge Deller , Sebastian Reichel , John Hubbard , Peter Xu , Masami Hiramatsu , Oleg Nesterov , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Rik van Riel , Harry Yoo , Juri Lelli , Vincent Guittot , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Arnd Bergmann , Muchun Song , Oscar Salvador , "Matthew Wilcox (Oracle)" , Jan Kara , Marc Zyngier , Oliver Upton , Catalin Marinas , Madhavan Srinivasan , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , "David S. Miller" , Andreas Larsson , Alexander Viro , Christian Brauner , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Youngjun Park , Johannes Weiner , Qi Zheng , Shakeel Butt , Axel Rasmussen , Yuanchu Xie , Wei Xu , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-usb@vger.kernel.org, linux-rdma@vger.kernel.org, selinux@vger.kernel.org, linux-sound@vger.kernel.org, bpf@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, fuse-devel@lists.linux.dev, Ihor Solodrai , Bert Karwatzki References: <20261013-b4-mmap-prepare-vma-flag-sanify-v6-0-1aa3c9b139f9@kernel.org> <20261013-b4-mmap-prepare-vma-flag-sanify-v6-30-1aa3c9b139f9@kernel.org> 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 10/13/26 17:05, Lorenzo Stoakes (ARM) wrote: > Introduce vma[_flags]_is_mm_backed() for the purposes of identifying > mappings which are mm-managed and whose contents were placed there by core > mm's own fault path - rather than a custom ->fault handler. > > Mappings not managed by core mm do not fall into this category, as they are > populated by their owner, and nor of course does memory-mapped I/O. > > We exclude fixed mappings as these have a layout core mm cannot assume > ordinary fault semantics over. > > hugetlb mappings are fixed mappings, but core mm owns them entirely, so > they are explicitly carved out as mm-backed, as the MADV_DODUMP check > already does. > > Use this functionality to update the madvise MADV_DODUMP check to test for > this rather than open-coding it. > > Also update vma_flags_can_merge() so it is written in terms of > vma_flags_is_mm_backed() - all mm-backed mappings can be merged except > hugetlb mappings, whose flags and fields do not completely describe them. > > Also update __thp_vma_allowable_orders() to use vma_is_mm_backed() rather > than testing for mergeability, which is irrelevant to this function. > > This replaces the VM_SPECIAL check which means it no longer checks for > VMA_IO_BIT, however this is safe as we have established the invariant that > mm-managed mappings may not set VMA_IO_BIT, so we implicitly include > these. > > No functional change intended. > > Acked-by: Zi Yan > Signed-off-by: Lorenzo Stoakes (ARM) > --- Acked-by: David Hildenbrand (Arm) -- Cheers, David