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 BBE9ACFD313 for ; Mon, 24 Nov 2025 14:11:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0B5C16B0027; Mon, 24 Nov 2025 09:11:59 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 065E66B0028; Mon, 24 Nov 2025 09:11:58 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E976D6B0029; Mon, 24 Nov 2025 09:11:58 -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 D53426B0027 for ; Mon, 24 Nov 2025 09:11:58 -0500 (EST) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 9505858D36 for ; Mon, 24 Nov 2025 14:11:58 +0000 (UTC) X-FDA: 84145689516.16.E31FBA0 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf06.hostedemail.com (Postfix) with ESMTP id A3F2C180012 for ; Mon, 24 Nov 2025 14:11:56 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=TjUGt8Li; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf06.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=1763993516; 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=KMDKfFvqxZF3OgYS2Y3qGBHTWecl6sSIcgPW0EPBoLA=; b=QF6pXeMcvlvWLXQqSZMrZJQ8dNdSM8Uiy8W0Wbj80wElLPJLq6W10kQS+3kEC5BgapJQGI oZH6Vl+hDybzimBatimFtADl8K6CvdN9urUSxMEI0WsKzFa1ZlUYyOQ6eRb4zg08Y+3Jyr l0zVCPnFMpeJFM4++JdapRfWaEbHTSU= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1763993516; a=rsa-sha256; cv=none; b=px/Ac0UcfYz5rsEkag9+VhtGbGVyFcNeCfxAxh8QU6ws1lANZ/fyfaTiSSnCFtZt7R/jcK 8f8/L2YUCM+DmH+uxMyy9Nkx3fr7hF4MAiaJOnXe1mU9cKHnT0XhlCKC0X2thtHZZSJqDb wglOmirWc1GFlgYDgZMUHMzbo5SGBH8= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=TjUGt8Li; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf06.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 123B2601A7; Mon, 24 Nov 2025 14:11:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EE78BC116C6; Mon, 24 Nov 2025 14:11:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763993515; bh=pKRds4IT+BzPKh2fxA3wO0tgnvzHdhCWGBCp+0CwG9A=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=TjUGt8Li6YfogSyMUKImhk9t7zCEyR/5lyaBjeNw6RcKDKrbRq6HnmNGUOxqptBCd dLRr5vxSkWtTK/HdcfyyhBGI6jbvcRygLDwJPNmugo/e/qBVwdADZJpApwewQnH0Lz Zvd3xoS+6vTxsekxWrHLixtrCO8PmynL3TGa54AYYvreiAeQp5nXHtEPY83/MIXq9v IDvhAooUaPXLRXgkrwnbgHUW6P169b7ay8AKZtPjbmGcLHflIqg6kF1HvRTZ7a8+u+ 51pYm9HXbc2JA+xZLuh0Y9NS3lb+de9hbRLWFhjCNgsTJpUFrYKe7BdliclaVXA64P 5nWYBjsK1rt0g== Message-ID: <9800804f-6e8a-4d08-8eb1-f114df6d6b7a@kernel.org> Date: Mon, 24 Nov 2025 15:11:44 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 07/12] mm: bail out of lazy_mmu_mode_* in interrupt context To: Kevin Brodsky , 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 , "Ritesh Harjani (IBM)" , Ryan Roberts , Suren Baghdasaryan , Thomas Gleixner , Venkat Rao Bagalkote , 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: <20251124132228.622678-1-kevin.brodsky@arm.com> <20251124132228.622678-8-kevin.brodsky@arm.com> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: <20251124132228.622678-8-kevin.brodsky@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: 4mw1r3fzf43wrafe7cjcfek5idru1179 X-Rspam-User: X-Rspamd-Queue-Id: A3F2C180012 X-Rspamd-Server: rspam10 X-HE-Tag: 1763993516-122136 X-HE-Meta: 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 M77WoF3d AuBmtP8B+neC4e/vjnUcho+WZyPwexhQDhHEDfuIfqyADnoBdW1UVvauujHpiH6r3xTNy7UL1I11Esf97VCEEU4ubETbbGwVafdwXFCmVkT1E989yEsMHM1oLK3rMBwoWEHkesCRoNKGTDR6IKJolYgXhZRL6m1Qs+QCPC5E2oMm7y6vV2WEsRnBmxRHM3jmBJRFjdseT4X6fdTAhHcVvo/wogZHDZInI3GOuKZGeSACjpbEtxmXksg6+N6/IgyJGXqr6RJfS4WGRYqr8p7jtmtxNfUyD+wktmKzyC3miGfySkdNKgmtDnA8ci9SIRSmhXlUHIK8eGzFZ8TGAkO6b07c77492Dh0A/aWNOYzsXHe8TbrvIB3cj5VVsiW3WxMbM1nvBjfwNviWHkb/VsoFvFLLwyuPkxPDrbdgqsnHWSPqYU8= 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 11/24/25 14:22, Kevin Brodsky wrote: > The lazy MMU mode cannot be used in interrupt context. This is > documented in , but isn't consistently handled > across architectures. > > arm64 ensures that calls to lazy_mmu_mode_* have no effect in > interrupt context, because such calls do occur in certain > configurations - see commit b81c688426a9 ("arm64/mm: Disable barrier > batching in interrupt contexts"). Other architectures do not check > this situation, most likely because it hasn't occurred so far. > > Let's handle this in the new generic lazy_mmu layer, in the same > fashion as arm64: bail out of lazy_mmu_mode_* if in_interrupt(). > Also remove the arm64 handling that is now redundant. > > Both arm64 and x86/Xen also ensure that any lazy MMU optimisation is > disabled while in interrupt (see queue_pte_barriers() and > xen_get_lazy_mode() respectively). This will be handled in the > generic layer in a subsequent patch. > > Signed-off-by: Kevin Brodsky > --- (resending as I pushed the wrong button there ...) Moving this patch earlier LGTM, hoping we don't get any unexpected surprises ... Acked-by: David Hildenbrand (Red Hat) -- Cheers David