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 F3AB6CCD1BF for ; Fri, 24 Oct 2025 15:05:21 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 543F38E00B0; Fri, 24 Oct 2025 11:05:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4CEA48E0042; Fri, 24 Oct 2025 11:05:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3E33F8E00B0; Fri, 24 Oct 2025 11:05:21 -0400 (EDT) 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 2BBA78E0042 for ; Fri, 24 Oct 2025 11:05:21 -0400 (EDT) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id BC5395DB0F for ; Fri, 24 Oct 2025 15:05:20 +0000 (UTC) X-FDA: 84033331200.25.4F6F95E Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf17.hostedemail.com (Postfix) with ESMTP id EA6694001D for ; Fri, 24 Oct 2025 15:05:18 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf17.hostedemail.com: domain of kevin.brodsky@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=kevin.brodsky@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1761318319; 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; bh=mFsntFKm3sLCSsUTazR6Zz09gRvrPjOBy+0/EZ6kZlE=; b=WEOw2bJ/8raeSkCU+dqanie8b99KAM5LSY3IK5Ya8/D7gzjH0dBeCYiNkyT5E1YRNVvRwc N2r+o9L/kiWV+lZCGbAZX/KrOkQ2h3SNX2Ki+Sd/qFoVK54Df2ra7e7ivWN/YpPRUWRzHz FNkyLe9xNKfqjFmMaP8Dx8PfawN0oY8= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1761318319; a=rsa-sha256; cv=none; b=8rJgKDE9fF8tMv8FMRhooWGr72x9dLpOsNRxN1+NOhJa2Ns8e9amUebA9RWv4kInw7TPmk /Y8pxDyUMVxQ3jeLbxaPGEu8mYo0l/fsE54zHYzcjWyU6lugTN0CU4RRFO9pe1tApjgYwR zMTXDRISV6n9CC4bIHndLuzCEJLEYdc= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf17.hostedemail.com: domain of kevin.brodsky@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=kevin.brodsky@arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 29D6E14BF; Fri, 24 Oct 2025 08:05:10 -0700 (PDT) Received: from [10.57.67.38] (unknown [10.57.67.38]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 519063F63F; Fri, 24 Oct 2025 08:05:10 -0700 (PDT) Message-ID: <6ed9f404-9939-4e9f-b5aa-4253bef46df1@arm.com> Date: Fri, 24 Oct 2025 17:05:07 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 11/13] x86/xen: use lazy_mmu_state when context-switching To: David Woodhouse , David Hildenbrand , 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" , "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 , Ryan Roberts , 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: <20251015082727.2395128-1-kevin.brodsky@arm.com> <20251015082727.2395128-12-kevin.brodsky@arm.com> <348e5f1c5a90e4ab0f14b4d997baf7169745bf04.camel@infradead.org> Content-Language: en-GB From: Kevin Brodsky In-Reply-To: <348e5f1c5a90e4ab0f14b4d997baf7169745bf04.camel@infradead.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam01 X-Stat-Signature: 7dhqn8eq639k7sp5gjr5dmgikgga4ytp X-Rspam-User: X-Rspamd-Queue-Id: EA6694001D X-HE-Tag: 1761318318-861729 X-HE-Meta: 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 0KmFpyRx 0IER+qBCaLIf5DpWHhkDk59N/g/9ZFrpyze3wyMfNRWQer2SXWeAjj8KSuaPJUMH1Wc4OTBZFFEZj66PjXPwU1eEUJbEXolKFZ3X31A9voe/iLFuaDfZuwI+QKazD66Q5rX8i9e3rE5ob/dG0HZkz2wpcpeniSjG7e447hPUAeRdx3sZeQR5YIMF9rGZwd3nUKzgV/4xi/3IBBE3Wf378+ItJslktlJq54UkgmEImCUzt22+3ND85NOfqaw== 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: On 24/10/2025 16:47, David Woodhouse wrote: > On Thu, 2025-10-23 at 22:06 +0200, David Hildenbrand wrote: >> On 15.10.25 10:27, Kevin Brodsky wrote: >>> We currently set a TIF flag when scheduling out a task that is in >>> lazy MMU mode, in order to restore it when the task is scheduled >>> again. >>> >>> The generic lazy_mmu layer now tracks whether a task is in lazy MMU >>> mode in task_struct::lazy_mmu_state. We can therefore check that >>> state when switching to the new task, instead of using a separate >>> TIF flag. >>> >>> Signed-off-by: Kevin Brodsky >>> --- >> >> Looks ok to me, but I hope we get some confirmation from x86 / xen >> folks. > > I know tglx has shouted at me in the past for precisely this reminder, > but you know you can test Xen guests under QEMU/KVM now and don't need > to actually run Xen? Has this been boot tested? I considered boot-testing a Xen guest (considering the Xen-specific changes in this series), but having no idea how to go about it I quickly gave up... Happy to follow instructions :) - Kevin