From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6FD5BCCFA1A for ; Wed, 12 Nov 2025 13:57:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6EA728E0016; Wed, 12 Nov 2025 08:57:54 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 69AFF8E0003; Wed, 12 Nov 2025 08:57:54 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5AFF08E0016; Wed, 12 Nov 2025 08:57:54 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 4538F8E0003 for ; Wed, 12 Nov 2025 08:57:54 -0500 (EST) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id E6AC9B9BF3 for ; Wed, 12 Nov 2025 13:57:53 +0000 (UTC) X-FDA: 84102108426.06.56977B7 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf25.hostedemail.com (Postfix) with ESMTP id 3B284A000B for ; Wed, 12 Nov 2025 13:57:52 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=uDdn5b0T; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf25.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1762955872; a=rsa-sha256; cv=none; b=YFE8Hm85XGQq+BPh89oEiYrCphS/EHosI+2U8zQnLHyc4U2ONbL5HW7Z8h2c1TswlSiTes YrcPyMuP6nr+HT1+gSVV63Wix13nzVQyQf6JwKUa9prES/GlKdKszs5FaU76Hzfoeu8Ldu LcpdPwqYjGGIPUGxQkjtA5NTBllen/A= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=uDdn5b0T; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf25.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1762955872; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=/iYFkq8EoSIFdFM4yiltEoa/A9Iy/iMJWrMfuUMJqAY=; b=GKSicMaT+rgUBIFQAeXm+KpJLXsMS7tp389Cy5M6C7BfHIMP52oBX6Cu2svpLejP1tQwO4 pVM6C/60TUaEfmQ46LAisQUW0aa3GO5qTeHwoH6GX5oXpnG2O1VtgtEYd8hin5UPofDlkv aWGZ8/uVztQs8/dw0pjgeWHo/uanyB0= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 6148D60213; Wed, 12 Nov 2025 13:57:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29847C2BCB4; Wed, 12 Nov 2025 13:57:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762955871; bh=wyYh5JA+N7mRZY7BRonX9hRu7lWf6kG2xADXz4mWKHk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=uDdn5b0TMd79Lh5gGh2J4WjGYOU7mL3bVuBbQ/VXgzY4nMQRUASwOOOn1wPdm3Cym W4XE28wEzp5MfEzdP2hqphehcMkmvAS/b8w6wcpUiLZxYE0rCMGLEp+rVCdW9qI4ba ocobM87q4/c0/j7wdbVyzm/yrXe8KetWir7vwxyUiRXtVNS/+8DnZ7OaB4HqMTf7u6 36VSYtBbbyHuGEXAGGvXe/GFkuJFAWR+xBF55ycy4xXYzkSJweCr6O/7vY6qeuk4iJ 2JAYXvNk5KDLXblAvdwOWYLaBc3JfMXId6w7fnEaMQeOyF/yR5GPTl+Yi8z7SCHe3i /nZPR2FUDupLg== Message-ID: Date: Wed, 12 Nov 2025 14:57:32 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 07/12] mm: enable lazy_mmu sections to nest To: Kevin Brodsky , Ryan Roberts , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Alexander Gordeev , Andreas Larsson , Andrew Morton , Boris Ostrovsky , Borislav Petkov , Catalin Marinas , Christophe Leroy , Dave Hansen , "David S. Miller" , David Woodhouse , "H. Peter Anvin" , Ingo Molnar , Jann Horn , Juergen Gross , "Liam R. Howlett" , Lorenzo Stoakes , Madhavan Srinivasan , Michael Ellerman , Michal Hocko , Mike Rapoport , Nicholas Piggin , Peter Zijlstra , Suren Baghdasaryan , Thomas Gleixner , Vlastimil Babka , Will Deacon , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org References: <20251029100909.3381140-1-kevin.brodsky@arm.com> <20251029100909.3381140-8-kevin.brodsky@arm.com> <999feffa-5d1d-42e3-bd3a-d949f2a9de9d@arm.com> <824bf705-e9d6-4eeb-9532-9059fa56427f@arm.com> <58fd1a6e-f2c4-421c-9b95-dea4b244a515@arm.com> <8f70692c-25a9-4bd0-94ab-43ab435e4b1b@arm.com> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 3B284A000B X-Stat-Signature: o1fdwegt5xkn44hdqsbn3rysaa6bh4y9 X-HE-Tag: 1762955872-918560 X-HE-Meta: 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 LRVWhJfb CIJ4m92fE2K2GdAFV66a4cyIBmp9e8WD447B5JAOOnieAW63YnkfOufvHj8ONjLsq1TQZ7zhOBUNFZTNPlFqTajXLEzvShEW24QfJ4Z97aIvLx6IEImS4UFhH4g4f76K3d8Mo62bvUv0PBWFTP8bkyZAxkhIveKuHkZqLRVlBYs3T8kCd6HRu/L+G8U3qAVJT/6Qd0eR8vPEO8iT9zsGCbRaUJeV8OgozZg6gJe7PKNptk8P9NcVzV/x3r2YZq3lrayN74M33uibq0lyfpi1XClpwj9J54jAGu12Yp8SNlcLRoo5IH5seDl03pg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: >>> >>> I don't really mind either way, but I don't see an immediate use for [C] >>> and [D] - the idea is that the paused section is short and controlled, >>> not made up of arbitrary calls. >> If my thinking above is correct, then I've already demonstrated that this is not >> the case. So I'd be inclined to go with [D] on the basis that it is the most robust. >> >> Keeping 2 nesting counts (enable and pause) feels pretty elegant to me and gives >> the fewest opportunities for surprises. > > Agreed, if we're going to allow enable() within a paused section, then > we might as well allow paused sections to nest too. The use-case is > clear, so I'm happy to go ahead and make those changes. > > David, any thoughts? I don't mind allowing nesting of pause(), so works for me. -- Cheers David