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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 C8047C433E0 for ; Tue, 26 Jan 2021 00:41:44 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3218D21D93 for ; Tue, 26 Jan 2021 00:41:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3218D21D93 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 889DF8D0066; Mon, 25 Jan 2021 19:41:42 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 839BF8D0065; Mon, 25 Jan 2021 19:41:42 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6DE828D0066; Mon, 25 Jan 2021 19:41:42 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0095.hostedemail.com [216.40.44.95]) by kanga.kvack.org (Postfix) with ESMTP id 50B048D0065 for ; Mon, 25 Jan 2021 19:41:42 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 1BB63181AF5C4 for ; Tue, 26 Jan 2021 00:41:42 +0000 (UTC) X-FDA: 77746073244.08.yard82_58018192758a Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin08.hostedemail.com (Postfix) with ESMTP id F2B891819E624 for ; Tue, 26 Jan 2021 00:41:41 +0000 (UTC) X-HE-Tag: yard82_58018192758a X-Filterd-Recvd-Size: 3892 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Tue, 26 Jan 2021 00:41:40 +0000 (UTC) IronPort-SDR: MRk59CLhOtCxgpLslIXI8w3h6zESU4RDRtZNd8m4zmVUU80mupPosVVxf/tUA72APeX3Fq+YIA 4bY4+QjMP5vA== X-IronPort-AV: E=McAfee;i="6000,8403,9875"; a="159603659" X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="159603659" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Jan 2021 16:41:39 -0800 IronPort-SDR: hOJfIs/C4PU8o2XSx/YV0eVbYfsSWcLbCKOxKOfY8Xe4I5nKGX89Oj08ePyqrk4jaGgPj3LsCi GfLcZQl2rr9w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="472556473" Received: from viggo.jf.intel.com (HELO localhost.localdomain) ([10.54.77.144]) by fmsmga001.fm.intel.com with ESMTP; 25 Jan 2021 16:41:39 -0800 Subject: [RFC][PATCH 04/13] mm/numa: node demotion data structure and lookup To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org,Dave Hansen ,yang.shi@linux.alibaba.com,rientjes@google.com,ying.huang@intel.com,dan.j.williams@intel.com,david@redhat.com,osalvador@suse.de From: Dave Hansen Date: Mon, 25 Jan 2021 16:34:19 -0800 References: <20210126003411.2AC51464@viggo.jf.intel.com> In-Reply-To: <20210126003411.2AC51464@viggo.jf.intel.com> Message-Id: <20210126003419.43281680@viggo.jf.intel.com> 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: From: Dave Hansen Prepare for the kernel to auto-migrate pages to other memory nodes with a user defined node migration table. This allows creating single migration target for each NUMA node to enable the kernel to do NUMA page migrations instead of simply reclaiming colder pages. A node with no target is a "terminal node", so reclaim acts normally there. The migration target does not fundamentally _need_ to be a single node, but this implementation starts there to limit complexity. If you consider the migration path as a graph, cycles (loops) in the graph are disallowed. This avoids wasting resources by constantly migrating (A->B, B->A, A->B ...). The expectation is that cycles will never be allowed. Signed-off-by: Dave Hansen Cc: Yang Shi Cc: David Rientjes Cc: Huang Ying Cc: Dan Williams Cc: David Hildenbrand Cc: osalvador -- changes in July 2020: - Remove loop from next_demotion_node() and get_online_mems(). This means that the node returned by next_demotion_node() might now be offline, but the worst case is that the allocation fails. That's fine since it is transient. --- b/mm/migrate.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff -puN mm/migrate.c~0006-node-Define-and-export-memory-migration-path mm/migrate.c --- a/mm/migrate.c~0006-node-Define-and-export-memory-migration-path 2021-01-25 16:23:09.553866709 -0800 +++ b/mm/migrate.c 2021-01-25 16:23:09.558866709 -0800 @@ -1161,6 +1161,22 @@ out: return rc; } +static int node_demotion[MAX_NUMNODES] = {[0 ... MAX_NUMNODES - 1] = NUMA_NO_NODE}; + +/** + * next_demotion_node() - Get the next node in the demotion path + * @node: The starting node to lookup the next node + * + * @returns: node id for next memory node in the demotion path hierarchy + * from @node; NUMA_NO_NODE if @node is terminal. This does not keep + * @node online or guarantee that it *continues* to be the next demotion + * target. + */ +int next_demotion_node(int node) +{ + return node_demotion[node]; +} + /* * Obtain the lock on page, remove all ptes and migrate the page * to the newly allocated page in newpage. _