From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1AEB9389DEA; Tue, 7 Apr 2026 06:53:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775544828; cv=none; b=Le2QUi84P9W4F13mTbYmCP+9sy9cSDMOQ5+Y4KUc7+LrPEEktuFtqXmnayoBIVtJoFffdyjRiygatr10/I1SBM3EYykAA44TfghauUl4tz/cFajCiP8NPmQGbAt2DQPsF47KdqgvNlm4qIDZTDrjeexyP4ixakpmLaKD0qLg6yU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775544828; c=relaxed/simple; bh=xmJOywtnqtcjtDrOIaLg4cNmmd9eqq3pTFEdQ1HGsDk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Rir+LCj3eAv9TyrY1hE5bWJtVJE04bpUZwtuZPjJ9Fl7H+K3gyRRp5df7OmLKOG6wbYD3KC1l2pXAhtazeNGM1NzXELeaQIiY+lTW0ta29DmdeAuRVSZ6qDDj9B8/VgLuVsGhs06t48ZdacQCgRJQY9nKj1sDrfNgCoUY/YtVYg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=gq19ZaG6; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="gq19ZaG6" 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 6B3F716F2; Mon, 6 Apr 2026 23:53:39 -0700 (PDT) Received: from [10.164.18.83] (unknown [10.164.18.83]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A6EB73F641; Mon, 6 Apr 2026 23:53:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1775544825; bh=xmJOywtnqtcjtDrOIaLg4cNmmd9eqq3pTFEdQ1HGsDk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=gq19ZaG6H/Z6QLLA361dNnxs7Rcoy1FFoxh2es/ZkM34A3iiH7Q0NWkQ9Xjf85a/V Cw84yhYE9dms8niScH613/FI3ApHX6Wc/QmkYVNEjsQk3N+7VxRQ/QXYkr1v8tdtC2 iPBeGS35uCwhoz4oVnSyTerqZzVYnRL5bM3gmw1g= Message-ID: Date: Tue, 7 Apr 2026 12:23:39 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] perf/events: Replace READ_ONCE() with standard pgtable accessors To: "David Hildenbrand (Arm)" , linux-mm@kvack.org, Andrew Morton Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260227062744.2215491-1-anshuman.khandual@arm.com> <1267a6c0-f8e7-4708-96da-4d131b5c6069@arm.com> Content-Language: en-US From: Anshuman Khandual In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 07/04/26 12:18 PM, David Hildenbrand (Arm) wrote: > On 4/7/26 05:28, Anshuman Khandual wrote: >> >> >> On 27/02/26 11:57 AM, Anshuman Khandual wrote: >>> Replace raw READ_ONCE() dereferences of pgtable entries with corresponding >>> standard page table accessors pxdp_get() in perf_get_pgtable_size(). These >>> accessors default to READ_ONCE() on platforms that don't override them. So >>> there is no functional change on such platforms. >>> >>> However arm64 platform is being extended to support 128 bit page tables via >>> a new architecture feature i.e FEAT_D128 in which case READ_ONCE() will not >>> provide required single copy atomic access for 128 bit page table entries. >>> Although pxdp_get() accessors can later be overridden on arm64 platform to >>> extend required single copy atomicity support on 128 bit entries. >>> >>> Cc: Andrew Morton >>> Cc: David Hildenbrand >>> Cc: Peter Zijlstra >>> Cc: Ingo Molnar >>> Cc: Arnaldo Carvalho de Melo >>> Cc: Namhyung Kim >>> Cc: linux-perf-users@vger.kernel.org >>> Cc: linux-mm@kvack.org >>> Cc: linux-kernel@vger.kernel.org >>> Acked-by: Peter Zijlstra (Intel) >>> Signed-off-by: Anshuman Khandual >>> --- >>> This patch applies both on v7.0-rc1 and mm-unstable. >>> >>> Part of the D128 series but independent. Hence could be considered on its own. >>> >>> https://lore.kernel.org/all/20260224051153.3150613-5-anshuman.khandual@arm.com/ >>> >>> Collected Peter's tag from an off list conversation. >> >> Gentle ping. >> >> Still don't see this patch in latest next-20260406. Hence just >> wondering which tree and branch this patch is being picked up ? > > It's a trivial change and the last generic code change required for you > arm64 D128 change, right? Right. > > I would assume this to go through the tip tree, but if Peter agrees we > could route this (mm) patch through the MM tree. > Sure