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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13B40C433FE for ; Tue, 18 Oct 2022 22:41:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 524616B0071; Tue, 18 Oct 2022 18:41:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4D5056B0072; Tue, 18 Oct 2022 18:41:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3C3046B0074; Tue, 18 Oct 2022 18:41:50 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 2DE516B0071 for ; Tue, 18 Oct 2022 18:41:50 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id D75AAA0C7E for ; Tue, 18 Oct 2022 22:41:49 +0000 (UTC) X-FDA: 80035543938.06.8CB18D1 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by imf23.hostedemail.com (Postfix) with ESMTP id E9C9414003C for ; Tue, 18 Oct 2022 22:41:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1666132908; x=1697668908; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=43nga7sHlYGp/WXO1HBW7Mr8hHzUz0ck5JawD+SCfMg=; b=GsXSB8mPkwYpCoe3g2zQYsVToBJ9L++A6ual/JKpc8QXDNf/OF9SyuFP doIwClcwTnz2zEwQJipsOKaS7OEw3/+2Wm/kW3ge1h4P4V6MnYUAoKcAA 037A/2m3y1HEFoLBS353pe3ZFVwFvCdxzmJXiVWH4a7iu0Km06go/S9IH E+4H2/HxlOcdq/ECQoTpkhq/+UGhiTbVJ0x5d0n1BI4N73TFPNwhuhrht aQtu4qVT3P872mN8/jFQZiuXDPzJVoxdVMbWPLXhIQJYIscQGiOcYwD15 tujHAKlFgztV40RC8JC+DtDXzq5hEqjF/CEdfTiZmRSlK/A2yTMjke9Tg A==; X-IronPort-AV: E=McAfee;i="6500,9779,10504"; a="285969915" X-IronPort-AV: E=Sophos;i="5.95,194,1661842800"; d="scan'208";a="285969915" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Oct 2022 15:41:46 -0700 X-IronPort-AV: E=McAfee;i="6500,9779,10504"; a="660032778" X-IronPort-AV: E=Sophos;i="5.95,194,1661842800"; d="scan'208";a="660032778" Received: from jjsopko-mobl.amr.corp.intel.com (HELO [10.213.163.40]) ([10.213.163.40]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Oct 2022 15:41:44 -0700 Message-ID: <35961c2f-08ab-9036-bc0c-6ede269ad3ec@intel.com> Date: Tue, 18 Oct 2022 15:41:43 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Subject: Re: [PATCHv10 09/15] x86: Expose untagging mask in /proc/$PID/arch_status Content-Language: en-US To: "Kirill A. Shutemov" Cc: Dave Hansen , Andy Lutomirski , Peter Zijlstra , x86@kernel.org, Kostya Serebryany , Andrey Ryabinin , Andrey Konovalov , Alexander Potapenko , Taras Madan , Dmitry Vyukov , "H . J . Lu" , Andi Kleen , Rick Edgecombe , Bharata B Rao , Jacob Pan , Ashok Raj , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20221018113358.7833-1-kirill.shutemov@linux.intel.com> <20221018113358.7833-10-kirill.shutemov@linux.intel.com> <20221018222419.oy2z2wanvwp2pnrm@box.shutemov.name> From: Dave Hansen In-Reply-To: <20221018222419.oy2z2wanvwp2pnrm@box.shutemov.name> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1666132908; a=rsa-sha256; cv=none; b=jzyh3Vl5CneQErM2hI+TC6wD2b47qwniwrDZQ6gGQWR1Ot8hfLc7uOLX6DrMQmMrAfY6hV zHrXQRHtAyHjJZe+5EThITbR+PfQZQFJ2VjdvJiadtCxMF5NKCt/w3+yvHWt9SUiQVowrv R0lt6LVllhbHAkKmVnOcfHE2l/KqT7Q= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=GsXSB8mP; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf23.hostedemail.com: domain of dave.hansen@intel.com designates 192.55.52.136 as permitted sender) smtp.mailfrom=dave.hansen@intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666132908; 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=X5o26AzaYbNeAR3WcHFDaCEQJwJRjb2doq9OC3w8sr0=; b=EvQvT+njK51oSLs2i50YfxaxFzOegytpNrITUC4lyeaaVhQXAmnEGP2F3aW/s2ZKG+DS+G OfbBJuOXL9HoqzmRE4fhxshuJTLut1xmf+Mdz3ku4NKcMCjw2iDLgt7SiRoyyxyXv5nMFR FmGgryJdB7tjFtNY+QWQX1t2Cs/fmCg= X-Rspamd-Server: rspam05 X-Rspam-User: X-Rspamd-Queue-Id: E9C9414003C Authentication-Results: imf23.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=GsXSB8mP; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf23.hostedemail.com: domain of dave.hansen@intel.com designates 192.55.52.136 as permitted sender) smtp.mailfrom=dave.hansen@intel.com X-Stat-Signature: c6h7fzdce7ynwjca1shtu1t9tquieetb X-HE-Tag: 1666132907-703144 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: On 10/18/22 15:24, Kirill A. Shutemov wrote: > On Tue, Oct 18, 2022 at 02:02:43PM -0700, Dave Hansen wrote: >> On 10/18/22 04:33, Kirill A. Shutemov wrote: >>> Add a line in /proc/$PID/arch_status to report untag_mask. It can be >>> used to find out LAM status of the process from the outside. It is >>> useful for debuggers. >> Considering that address masking is not x86-specific, it seems like this >> needs a better home (another file in /proc). > In generic /proc/$PID/status? Seems like a sane place to me. > And I'm not sure if it is a good idea at this stage. Semantics around tags > is not settled across architectures: somewhere it is per-thread, somewhere > per-process, somewhere it is global. > > Maybe keep it arch-specific? Yeah, but all of those things could be served by a thread-specific ABI. The per-thread ABI won't enumerate the scope of the thing, of course. But, it _can_ precisely communicate what semantics the thread has.