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 A17BF391E4B; Fri, 2 Oct 2026 14:00:05 +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=1790949607; cv=none; b=QkUPgTqxl609eP1+F3jy3N+B62etp6x5Ssw0FZzbSBAyHXUWKWoydd34vVbOZ2LCGzV0BpskvT613kUKzPQgQ71+gusNnp/PCwNxti03LrrAZCiW4SwoHHfYM7BgARO5R3O9LEFfvnuAn7IMGefciKgHO0DxisgDKpyNnVQvayw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790949607; c=relaxed/simple; bh=FWeJKgDAlOAYIHixYG049WYkZWEDE53qc96LN8n5q4c=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=cDY3D4MTatl1LHX+mwEiSxA/OGsiLNQ0osvB85oECy/c87fFqNuwUscQw2ZCPUXdqwb4wXzVO2+bbZ82adqH7ctl74wfZ6OG0mpLxSrbAvXI9ik4VFNy8a8JckqtrkgirlzYtEMG1RXDEigHpWZUCSEPNHQnHdxe7WE6sR0LZGQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lCWn9cDF; 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="lCWn9cDF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 501EB1F000FF; Fri, 2 Oct 2026 13:59:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790949604; bh=JrJqgz6XBqr0tqvrPwuWu3EbEV7kVO9oxqBplkAGfJ8=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=lCWn9cDFMJm4u1OpaqsPaifDSAYxVJq/u9IjTjW8VHaCqg4YN9JjvyLsXvAqt1QNy kXjsxEDBQVVSiIroM8JVx8jdbn5z+D3ALO2UR7Dt4oCwXbWLHzPI9wUTMqgwfU7Krj IZwSxYhHFuMLnMs6YBDMSwGCVs4RhT6DtJPo3InMpggMiPIDm38MOeNSzD7sXk23e2 RWLEF3oKpPBtzGR/mrLgeY6/R3hf0OeJ04oxiHGDqrqFlOeh7T6MsnVwgAIQ5juixO EyqksyZMc+ThciZZQxHOhRow8uXbh8X8CGyWqfIqAq62o4uBFfPnhBhtXmHvotijgD QT9fd+pxtot2w== Date: Fri, 2 Oct 2026 14:59:35 +0100 From: "Lorenzo Stoakes (ARM)" To: "David Hildenbrand (Arm)" Cc: 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" , Jaya Kumar , 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 , 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 Subject: Re: [PATCH v3 31/40] mm/vma: introduce vma[_flags]_is_persistent() Message-ID: References: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-0-4583d8a23bca@kernel.org> <20260917-b4-mmap-prepare-vma-flag-sanify-v3-31-4583d8a23bca@kernel.org> <9bbdf4e8-6984-4477-a183-f0b236047381@kernel.org> <3557015d-23dd-41ef-9832-78b58587f3f4@kernel.org> <81e1e5ae-0aab-4584-81e6-3fc9c2634d07@kernel.org> <2e5a4e6c-8f9c-4050-8998-454b83f4823b@kernel.org> <3387642b-c39f-4f19-ba0c-267bbd2fe91d@kernel.org> 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=us-ascii Content-Disposition: inline In-Reply-To: <3387642b-c39f-4f19-ba0c-267bbd2fe91d@kernel.org> On Fri, Oct 02, 2026 at 03:11:27PM +0200, David Hildenbrand (Arm) wrote: > I'd be very happy if we could find a clear way to describe "this is what we call > user memory: anon+pagecache", if that could come handy in such a context. Rather than arguing about it, how about shifting things to 'what backs the mapping' and something like: /* big long kdoc... */ static inline bool vma_flags_is_mm_backed(const vma_flags_t *flags) { /* hugetlb is a fixed mapping, but the mm owns it entirely. */ if (vma_flags_is_hugetlb(flags)) return true; /* * Kernel-owned mappings are populated by their owner, and fixed mappings * have a layout the mm cannot assume ordinary fault semantics over. */ if (vma_flags_is_kernel_owned(flags) || vma_flags_is_fixed_mapping(flags)) return false; /* The mm has promised it may discard droppable memory at any time. */ return !vma_flags_test_single_mask(flags, VMA_DROPPABLE); } ? -- Cheers, Lorenzo