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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, 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 02E62C4360F for ; Thu, 21 Mar 2019 20:03:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C7F48218B0 for ; Thu, 21 Mar 2019 20:02:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728831AbfCUUC5 (ORCPT ); Thu, 21 Mar 2019 16:02:57 -0400 Received: from mga06.intel.com ([134.134.136.31]:5164 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728093AbfCUUC4 (ORCPT ); Thu, 21 Mar 2019 16:02:56 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Mar 2019 13:02:56 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,254,1549958400"; d="scan'208";a="309246233" Received: from unknown (HELO localhost.lm.intel.com) ([10.232.112.69]) by orsmga005.jf.intel.com with ESMTP; 21 Mar 2019 13:02:56 -0700 From: Keith Busch To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-nvdimm@lists.01.org Cc: Dave Hansen , Dan Williams , Keith Busch Subject: [PATCH 1/5] node: Define and export memory migration path Date: Thu, 21 Mar 2019 14:01:53 -0600 Message-Id: <20190321200157.29678-2-keith.busch@intel.com> X-Mailer: git-send-email 2.13.6 In-Reply-To: <20190321200157.29678-1-keith.busch@intel.com> References: <20190321200157.29678-1-keith.busch@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Prepare for the kernel to auto-migrate pages to other memory nodes with a user defined node migration table. A user may create a single 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: Keith Busch --- Documentation/ABI/stable/sysfs-devices-node | 11 ++++- drivers/base/node.c | 73 +++++++++++++++++++++++++++++ include/linux/node.h | 6 +++ 3 files changed, 89 insertions(+), 1 deletion(-) diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node index 3e90e1f3bf0a..7439e1845e5d 100644 --- a/Documentation/ABI/stable/sysfs-devices-node +++ b/Documentation/ABI/stable/sysfs-devices-node @@ -90,4 +90,13 @@ Date: December 2009 Contact: Lee Schermerhorn Description: The node's huge page size control/query attributes. - See Documentation/admin-guide/mm/hugetlbpage.rst \ No newline at end of file + See Documentation/admin-guide/mm/hugetlbpage.rst + +What: /sys/devices/system/node/nodeX/migration_path +Data March 2019 +Contact: Linux Memory Management list +Description: + Defines which node the kernel should attempt to migrate this + node's pages to when this node requires memory reclaim. A + negative value means this is a terminal node and memory can not + be reclaimed through kernel managed migration. diff --git a/drivers/base/node.c b/drivers/base/node.c index 86d6cd92ce3d..20a90905555f 100644 --- a/drivers/base/node.c +++ b/drivers/base/node.c @@ -59,6 +59,10 @@ static inline ssize_t node_read_cpulist(struct device *dev, static DEVICE_ATTR(cpumap, S_IRUGO, node_read_cpumask, NULL); static DEVICE_ATTR(cpulist, S_IRUGO, node_read_cpulist, NULL); +#define TERMINAL_NODE -1 +static int node_migration[MAX_NUMNODES] = {[0 ... MAX_NUMNODES - 1] = TERMINAL_NODE}; +static DEFINE_SPINLOCK(node_migration_lock); + #define K(x) ((x) << (PAGE_SHIFT - 10)) static ssize_t node_read_meminfo(struct device *dev, struct device_attribute *attr, char *buf) @@ -233,6 +237,74 @@ static ssize_t node_read_distance(struct device *dev, } static DEVICE_ATTR(distance, S_IRUGO, node_read_distance, NULL); +static ssize_t migration_path_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + return sprintf(buf, "%d\n", node_migration[dev->id]); +} + +static ssize_t migration_path_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + int i, err, nid = dev->id; + nodemask_t visited = NODE_MASK_NONE; + long next; + + err = kstrtol(buf, 0, &next); + if (err) + return -EINVAL; + + if (next < 0) { + spin_lock(&node_migration_lock); + WRITE_ONCE(node_migration[nid], TERMINAL_NODE); + spin_unlock(&node_migration_lock); + return count; + } + if (next > MAX_NUMNODES || !node_online(next)) + return -EINVAL; + + /* + * Follow the entire migration path from 'nid' through the point where + * we hit a TERMINAL_NODE. + * + * Don't allow looped migration cycles in the path. + */ + node_set(nid, visited); + spin_lock(&node_migration_lock); + for (i = next; node_migration[i] != TERMINAL_NODE; + i = node_migration[i]) { + /* Fail if we have visited this node already */ + if (node_test_and_set(i, visited)) { + spin_unlock(&node_migration_lock); + return -EINVAL; + } + } + WRITE_ONCE(node_migration[nid], next); + spin_unlock(&node_migration_lock); + + return count; +} +static DEVICE_ATTR_RW(migration_path); + +/** + * next_migration_node() - Get the next node in the migration path + * @current_node: The starting node to lookup the next node + * + * @returns: node id for next memory node in the migration path hierarchy from + * @current_node; -1 if @current_node is terminal or its migration + * node is not online. + */ +int next_migration_node(int current_node) +{ + int nid = READ_ONCE(node_migration[current_node]); + + if (nid >= 0 && node_online(nid)) + return nid; + return TERMINAL_NODE; +} + static struct attribute *node_dev_attrs[] = { &dev_attr_cpumap.attr, &dev_attr_cpulist.attr, @@ -240,6 +312,7 @@ static struct attribute *node_dev_attrs[] = { &dev_attr_numastat.attr, &dev_attr_distance.attr, &dev_attr_vmstat.attr, + &dev_attr_migration_path.attr, NULL }; ATTRIBUTE_GROUPS(node_dev); diff --git a/include/linux/node.h b/include/linux/node.h index 257bb3d6d014..af46c7a8b94f 100644 --- a/include/linux/node.h +++ b/include/linux/node.h @@ -67,6 +67,7 @@ static inline int register_one_node(int nid) return error; } +extern int next_migration_node(int current_node); extern void unregister_one_node(int nid); extern int register_cpu_under_node(unsigned int cpu, unsigned int nid); extern int unregister_cpu_under_node(unsigned int cpu, unsigned int nid); @@ -115,6 +116,11 @@ static inline void register_hugetlbfs_with_node(node_registration_func_t reg, node_registration_func_t unreg) { } + +static inline int next_migration_node(int current_node) +{ + return -1; +} #endif #define to_node(device) container_of(device, struct node, dev) -- 2.14.4