From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 41461372B4D; Fri, 20 Mar 2026 08:59:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773997169; cv=none; b=XUUzUjyHQCBhICuDhertsp5JK4EluiZ4Np2uTUHcsfNUxlhUtMCO2a+I6eSWe5HmunLDK2Nc97BqFrD49CwbSm8FleL2c4x5xgKyOldAKvVVFB17P1yuMW3kC9w5WfK3zf+OG+EU0M6UUzmpa/1kJqVvBMFSJ49QXqPq88hRaXo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773997169; c=relaxed/simple; bh=gZ7mo8VD+NAhXZQb0GYWny9AT9mHJxVOkGXSXRSlXkU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=A6ZIkh7nwpqF8VVKkDI6lFDA1xEDn4yv3VtuIK5FFhRh5xL2C4TdSTHKRs/169d0y/FAXOy2shvNaBIhi5lBvqgcGKY1Eb6lacA0J8cT5tCyUsGcgSU9IWJzaXLGlkseix+GHxkELxS9XFhbqb3RQJhuLHwCPctHZBfuiDemWzY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Vnv5g+fa; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Vnv5g+fa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 99035C4CEF7; Fri, 20 Mar 2026 08:59:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773997168; bh=gZ7mo8VD+NAhXZQb0GYWny9AT9mHJxVOkGXSXRSlXkU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Vnv5g+fajJemAepqRKZRz47c22+umNsA8K+bcibnuhBXHBu1d5YmKqWsG7qOfUFHJ CztV2PyO5tXV2ndgWUvx38ZhYgi/lqkSfU/R+xvcHnxYaqLoT/e6BRXTA0NdY6badP onDLOW/x64CNFEUrBONrSFSXSn2B8FQntJuy/TT5vt3gBjuLsep153gxDZT/dirYhC CVXFpifY9igf7fwFZwHhAhTf6uDN0JdiB+PEafeRbGrcMqNb+21IkikxadesfcAOxw W1QaWfzU+BhIh3qR/LFIA31TyjFUkVqrJLl/fZ5m//RUqAkbCbCMSFvmboEAlRrHUw pulfK6egziujA== Message-ID: Date: Fri, 20 Mar 2026 09:59:15 +0100 Precedence: bulk X-Mailing-List: linux-hexagon@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 15/23] mm: introduce vma_flags_count() and vma[_flags]_test_single_mask() Content-Language: en-US To: "Lorenzo Stoakes (Oracle)" , Andrew Morton Cc: David Hildenbrand , "Liam R . Howlett" , Jann Horn , Pedro Falcato , Mike Rapoport , Suren Baghdasaryan , Kees Cook , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vineet Gupta , Russell King , Catalin Marinas , Will Deacon , Brian Cain , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , Dinh Nguyen , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Richard Weinberger , Anton Ivanov , Johannes Berg , Alexander Viro , Christian Brauner , Jan Kara , Xu Xin , Chengming Zhou , Michal Hocko , Paul Moore , Stephen Smalley , Ondrej Mosnacek , linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-hexagon@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-um@lists.infradead.org, linux-fsdevel@vger.kernel.org, selinux@vger.kernel.org References: <02a6b26542ab70d60175e0125cff5fd00073c7ae.1773846935.git.ljs@kernel.org> From: "Vlastimil Babka (SUSE)" In-Reply-To: <02a6b26542ab70d60175e0125cff5fd00073c7ae.1773846935.git.ljs@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/18/26 16:50, Lorenzo Stoakes (Oracle) wrote: > vma_flags_count() determines how many bits are set in VMA flags, using > bitmap_weight(). > > vma_flags_test_single_mask() determines if a vma_flags_t set of flags > contains a single flag specified as another vma_flags_t value, or if the > sought flag mask is empty, it is defined to return false. > > This is useful when we want to declare a VMA flag as optionally a single > flag in a mask or empty depending on kernel configuration. > > This allows us to have VM_NONE-like semantics when checking whether the > flag is set. > > In a subsequent patch, we introduce the use of VMA_DROPPABLE of type > vma_flags_t using precisely these semantics. > > It would be actively confusing to use vma_flags_test_any_single_mask() for > this (and vma_flags_test_all_mask() is not correct to use here, as it > trivially returns true when tested against an empty vma flags mask). > > We introduce vma_flags_count() to be able to assert that the compared flag > mask is singular or empty, checked when CONFIG_DEBUG_VM is enabled. > > Also update the VMA tests as part of this change. > > Signed-off-by: Lorenzo Stoakes (Oracle) Acked-by: Vlastimil Babka (SUSE)