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=-9.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 699BCC677D4 for ; Mon, 8 Oct 2018 15:26:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2FF08214FA for ; Mon, 8 Oct 2018 15:26:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="rjiFsfdj" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2FF08214FA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 S1728168AbeJHWie (ORCPT ); Mon, 8 Oct 2018 18:38:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:57232 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728114AbeJHWie (ORCPT ); Mon, 8 Oct 2018 18:38:34 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 93C252150F; Mon, 8 Oct 2018 15:26:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1539012379; bh=dErdjsP5SAPENzAiG8aXAmFnGAM3UHEYzdW6dYxW1xU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rjiFsfdjLcYT7+FKLZsv2iFNTqDdY5++rFZxoTOntGk3EhyXua0PY6DOQIJdxs8Ri 8+Uw/fq6DzgMK4WxfXQILzGZY2rXfsR64YNAX82+BCnleF9+STfRBlIwm/Jb2Tv7bX Emow3kjJ/QPpMgH8y8FaI44s16R6FQk9xu2WHO3M= From: Sasha Levin To: stable@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Srikar Dronamraju , Michael Ellerman , Sasha Levin Subject: [PATCH AUTOSEL 4.18 56/58] powerpc/numa: Use associativity if VPHN hcall is successful Date: Mon, 8 Oct 2018 11:25:21 -0400 Message-Id: <20181008152523.70705-56-sashal@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181008152523.70705-1-sashal@kernel.org> References: <20181008152523.70705-1-sashal@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Srikar Dronamraju [ Upstream commit 2483ef056f6e42f61cd266452e2841165dfe1b5c ] Currently associativity is used to lookup node-id even if the preceding VPHN hcall failed. However this can cause CPU to be made part of the wrong node, (most likely to be node 0). This is because VPHN is not enabled on KVM guests. With 2ea6263 ("powerpc/topology: Get topology for shared processors at boot"), associativity is used to set to the wrong node. Hence KVM guest topology is broken. For example : A 4 node KVM guest before would have reported. [root@localhost ~]# numactl -H available: 4 nodes (0-3) node 0 cpus: 0 1 2 3 node 0 size: 1746 MB node 0 free: 1604 MB node 1 cpus: 4 5 6 7 node 1 size: 2044 MB node 1 free: 1765 MB node 2 cpus: 8 9 10 11 node 2 size: 2044 MB node 2 free: 1837 MB node 3 cpus: 12 13 14 15 node 3 size: 2044 MB node 3 free: 1903 MB node distances: node 0 1 2 3 0: 10 40 40 40 1: 40 10 40 40 2: 40 40 10 40 3: 40 40 40 10 Would now report: [root@localhost ~]# numactl -H available: 4 nodes (0-3) node 0 cpus: 0 2 3 4 5 6 7 8 9 10 11 12 13 14 15 node 0 size: 1746 MB node 0 free: 1244 MB node 1 cpus: node 1 size: 2044 MB node 1 free: 2032 MB node 2 cpus: 1 node 2 size: 2044 MB node 2 free: 2028 MB node 3 cpus: node 3 size: 2044 MB node 3 free: 2032 MB node distances: node 0 1 2 3 0: 10 40 40 40 1: 40 10 40 40 2: 40 40 10 40 3: 40 40 40 10 Fix this by skipping associativity lookup if the VPHN hcall failed. Fixes: 2ea626306810 ("powerpc/topology: Get topology for shared processors at boot") Signed-off-by: Srikar Dronamraju Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin --- arch/powerpc/mm/numa.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c index b5a71baedbc2..59d07bd5374a 100644 --- a/arch/powerpc/mm/numa.c +++ b/arch/powerpc/mm/numa.c @@ -1204,7 +1204,9 @@ int find_and_online_cpu_nid(int cpu) int new_nid; /* Use associativity from first thread for all siblings */ - vphn_get_associativity(cpu, associativity); + if (vphn_get_associativity(cpu, associativity)) + return cpu_to_node(cpu); + new_nid = associativity_to_nid(associativity); if (new_nid < 0 || !node_possible(new_nid)) new_nid = first_online_node; -- 2.17.1