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 X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D3525C00449 for ; Wed, 3 Oct 2018 22:18:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A0631213A2 for ; Wed, 3 Oct 2018 22:18:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A0631213A2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727164AbeJDFI5 (ORCPT ); Thu, 4 Oct 2018 01:08:57 -0400 Received: from mga02.intel.com ([134.134.136.20]:62846 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725922AbeJDFI5 (ORCPT ); Thu, 4 Oct 2018 01:08:57 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Oct 2018 15:18:39 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,337,1534834800"; d="scan'208";a="91965083" Received: from rchatre-s.jf.intel.com ([10.54.70.76]) by fmsmga002.fm.intel.com with ESMTP; 03 Oct 2018 15:17:41 -0700 From: Reinette Chatre To: tglx@linutronix.de, fenghua.yu@intel.com, tony.luck@intel.com Cc: jithu.joseph@intel.com, gavin.hindman@intel.com, dave.hansen@intel.com, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org, Reinette Chatre Subject: [PATCH V2 0/3] x86/intel_rdt: Fix exclusive mode with CDP resources Date: Wed, 3 Oct 2018 15:17:00 -0700 Message-Id: X-Mailer: git-send-email 2.17.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Changes in V2: - Have the new rdt_cdp_peer_get() return EINVAL instead of ENOENT when only one of the CDP peers have a rdt_domain associated with it. - Rename _rdtgroup_cbm_overlaps() to __rdtgroup_cbm_overlaps() to stand out more. - Fix kernel-doc to match function parameter name. - Rename rdtgroup_cbm_overlaps()'s _cbm function parameter to cbm. - Simplify the code in rdtgroup_cbm_overlaps() to make the flow more obvious. Nothing (apart from diffstat) changed below since original submission. Dear Maintainers, CDP resources do not currently behave as expected when there are resource groups with mode 'exclusive'. In the example below it was possible to create two resource groups, p1 and p2, that are both in exclusive mode but their usage of the underlying L2 cache actually overlaps. root@glk:/sys/fs/resctrl# ls cpus cpus_list info mode p1 p2 schemata size tasks root@glk:/sys/fs/resctrl# cat schemata L2DATA:0=fff0 L2CODE:0=fff0 root@glk:/sys/fs/resctrl# cat mode shareable root@glk:/sys/fs/resctrl# cat p1/schemata L2DATA:0=0003 L2CODE:0=000c root@glk:/sys/fs/resctrl# cat p1/mode exclusive root@glk:/sys/fs/resctrl# cat p2/schemata L2DATA:0=000c L2CODE:0=0003 root@glk:/sys/fs/resctrl# cat p2/mode exclusive root@glk:/sys/fs/resctrl# cat info/L2CODE/bit_usage 0=SSSSSSSSSSSSEEEE root@glk:/sys/fs/resctrl# cat info/L2DATA/bit_usage 0=SSSSSSSSSSSSEEEE root@glk:/sys/fs/resctrl# In the above example, the CBM of L2DATA in p1 overlaps with the CBM of L2CODE in p2 while they are both in exclusive mode. While it may reflect no overlap among the L2DATA resources specifically it does actually imply overlap of use of the underlying hardware that is not the intention of 'exclusive' mode. This happens because the current implementation treats L2CODE and L2DATA as totally independent, when it is actually referring to the same underlying hardware. This series fixes the potential for overlap of hardware resource use when resource groups are in 'exclusive' mode by ensuring that if there is a CDP peer on the same hardware then any overlap test would consider it also. Allocations of data and code resources within the same exclusive resource group are allowed to overlap. Your feedback will be greatly appreciated. Reinette Reinette Chatre (3): x86/intel_rdt: Introduce utility to obtain CDP peer x86/intel_rdt: CBM overlap should also check for overlap with CDP peer x86/intel_rdt: Fix initial allocation to consider CDP arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 133 ++++++++++++++++++++++- 1 file changed, 127 insertions(+), 6 deletions(-) -- 2.17.0