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 C774530C603 for ; Mon, 22 Sep 2025 13:15:03 +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=1758546903; cv=none; b=hwUHyby2r5fa5cvaUF8scUwuXuelCnVo7rx6oHdPL9bMH1tSjCszgS3ckjtsvoE1u3qiSSKISXjAfGQdY9cuRkG9oXb2UicqtzqnHb9SNnMD2WBOQmnozYdosB1vKhWfJ4HOUMMRmpiQ2vSh5YnSXYP2wyitFMl4Jrquba5NxNY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758546903; c=relaxed/simple; bh=qjcfXLp3AdjFsxFqfhoPlQvU2ruch20geThD74U3Oxk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=EAR3cAUAK+TcZRSFtt08Xb4A1+EA7tQcPwCdYbAAL5HVzwkAu6PD8g7Wni3LZZo8FD8ODLziYOMPJtLKuk3l3ZUO8O49LvdrgWHbLEJdV4OA8Yzu7zLZ/MoUI5YthFNKhz9iclD9BhhKiNrLFNfuW/4TnjJZXIYiFG4CJ00WW1A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WQXzfxqE; 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="WQXzfxqE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 28763C4CEF7; Mon, 22 Sep 2025 13:15:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758546903; bh=qjcfXLp3AdjFsxFqfhoPlQvU2ruch20geThD74U3Oxk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WQXzfxqEBkXsvV/5O9r23tMytKaOJxHZ9tJbVyrTZa6N5VhughdZFdPTfLTeQR2Vs mXhVeMM69afE1M9rFlpV/6JZ0b1zGkkwNSkka2Zbeb1JBh+uht96wXvy9XHO40BtRO /6H0yOn1KngO7a5PTnPJxFw9eo5z7n2Zx7XEHZITNi8uxBOaivePpwP5cO49JGFmQ2 NemIirxWtiqPKZ1qmkQQvSte2vlGwdMHhex887ZISrpRc6BIaIP1WIX4PEe6y4GJTX 9VYUZCwr6nTKjvbz1iwhCs/c35Xxni1B14bN+9DkEPjwHAzxe2hzKDiTYAZZVz6viY v+7UUtRFx/aUA== From: Will Deacon To: catalin.marinas@arm.com, Dev Jain Cc: kernel-team@android.com, Will Deacon , anshuman.khandual@arm.com, quic_zhenhuah@quicinc.com, ryan.roberts@arm.com, kevin.brodsky@arm.com, yangyicong@hisilicon.com, joey.gouly@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, david@redhat.com, mark.rutland@arm.com, urezki@gmail.com, jthoughton@google.com Subject: Re: [PATCH v6] arm64: Enable vmalloc-huge with ptdump Date: Mon, 22 Sep 2025 14:14:46 +0100 Message-Id: <175853832495.3123711.10100627692023962115.b4-ty@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250922064126.63016-1-dev.jain@arm.com> References: <20250922064126.63016-1-dev.jain@arm.com> 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="utf-8" Content-Transfer-Encoding: 8bit On Mon, 22 Sep 2025 12:11:26 +0530, Dev Jain wrote: > Our goal is to move towards enabling vmalloc-huge by default on arm64 so > as to reduce TLB pressure. Therefore, we need a way to analyze the portion > of block mappings in vmalloc space we can get on a production system; this > can be done through ptdump, but currently we disable vmalloc-huge if > CONFIG_PTDUMP_DEBUGFS is on. The reason is that lazy freeing of kernel > pagetables via vmap_try_huge_pxd() may race with ptdump, so ptdump > may dereference a bogus address. > > [...] Applied to arm64 (for-next/mm), thanks! [1/1] arm64: Enable vmalloc-huge with ptdump https://git.kernel.org/arm64/c/fa93b45fd397 Cheers, -- Will https://fixes.arm64.dev https://next.arm64.dev https://will.arm64.dev