topology.h

  1/*
  2 * include/linux/topology.h
  3 *
  4 * Written by: Matthew Dobson, IBM Corporation
  5 *
  6 * Copyright (C) 2002, IBM Corp.
  7 *
  8 * All rights reserved.
  9 *
 10 * This program is free software; you can redistribute it and/or modify
 11 * it under the terms of the GNU General Public License as published by
 12 * the Free Software Foundation; either version 2 of the License, or
 13 * (at your option) any later version.
 14 *
 15 * This program is distributed in the hope that it will be useful, but
 16 * WITHOUT ANY WARRANTY; without even the implied warranty of
 17 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 18 * NON INFRINGEMENT.  See the GNU General Public License for more
 19 * details.
 20 *
 21 * You should have received a copy of the GNU General Public License
 22 * along with this program; if not, write to the Free Software
 23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 24 *
 25 * Send feedback to <colpatch@us.ibm.com>
 26 */
 27#ifndef _LINUX_TOPOLOGY_H
 28#define _LINUX_TOPOLOGY_H
 29
 30#include <linux/arch_topology.h>
 31#include <linux/cpumask.h>
 32#include <linux/nodemask.h>
 33#include <linux/bitops.h>
 34#include <linux/mmzone.h>
 35#include <linux/smp.h>
 36#include <linux/percpu.h>
 37#include <asm/topology.h>
 38
 39#ifndef nr_cpus_node
 40#define nr_cpus_node(node) cpumask_weight(cpumask_of_node(node))
 41#endif
 42
 43int arch_update_cpu_topology(void);
 44
 45/* Conform to ACPI 2.0 SLIT distance definitions */
 46#define LOCAL_DISTANCE		10
 47#define REMOTE_DISTANCE		20
 48#define DISTANCE_BITS           8
 49#ifndef node_distance
 50#define node_distance(from,to)	((from) == (to) ? LOCAL_DISTANCE : REMOTE_DISTANCE)
 51#endif
 52#ifndef RECLAIM_DISTANCE
 53/*
 54 * If the distance between nodes in a system is larger than RECLAIM_DISTANCE
 55 * (in whatever arch specific measurement units returned by node_distance())
 56 * and node_reclaim_mode is enabled then the VM will only call node_reclaim()
 57 * on nodes within this distance.
 58 */
 59#define RECLAIM_DISTANCE 30
 60#endif
 61
 62/*
 63 * The following tunable allows platforms to override the default node
 64 * reclaim distance (RECLAIM_DISTANCE) if remote memory accesses are
 65 * sufficiently fast that the default value actually hurts
 66 * performance.
 67 *
 68 * AMD EPYC machines use this because even though the 2-hop distance
 69 * is 32 (3.2x slower than a local memory access) performance actually
 70 * *improves* if allowed to reclaim memory and load balance tasks
 71 * between NUMA nodes 2-hops apart.
 72 */
 73extern int __read_mostly node_reclaim_distance;
 74
 75#ifndef PENALTY_FOR_NODE_WITH_CPUS
 76#define PENALTY_FOR_NODE_WITH_CPUS	(1)
 77#endif
 78
 79#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
 80DECLARE_PER_CPU(int, numa_node);
 81
 82#ifndef numa_node_id
 83/* Returns the number of the current Node. */
 84static inline int numa_node_id(void)
 85{
 86	return raw_cpu_read(numa_node);
 87}
 88#endif
 89
 90#ifndef cpu_to_node
 91static inline int cpu_to_node(int cpu)
 92{
 93	return per_cpu(numa_node, cpu);
 94}
 95#endif
 96
 97#ifndef set_numa_node
 98static inline void set_numa_node(int node)
 99{
100	this_cpu_write(numa_node, node);
101}
102#endif
103
104#ifndef set_cpu_numa_node
105static inline void set_cpu_numa_node(int cpu, int node)
106{
107	per_cpu(numa_node, cpu) = node;
108}
109#endif
110
111#else	/* !CONFIG_USE_PERCPU_NUMA_NODE_ID */
112
113/* Returns the number of the current Node. */
114#ifndef numa_node_id
115static inline int numa_node_id(void)
116{
117	return cpu_to_node(raw_smp_processor_id());
118}
119#endif
120
121#endif	/* [!]CONFIG_USE_PERCPU_NUMA_NODE_ID */
122
123#ifdef CONFIG_HAVE_MEMORYLESS_NODES
124
125/*
126 * N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
127 * It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
128 * Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem().
129 */
130DECLARE_PER_CPU(int, _numa_mem_);
131
132#ifndef set_numa_mem
133static inline void set_numa_mem(int node)
134{
135	this_cpu_write(_numa_mem_, node);
136}
137#endif
138
139#ifndef numa_mem_id
140/* Returns the number of the nearest Node with memory */
141static inline int numa_mem_id(void)
142{
143	return raw_cpu_read(_numa_mem_);
144}
145#endif
146
147#ifndef cpu_to_mem
148static inline int cpu_to_mem(int cpu)
149{
150	return per_cpu(_numa_mem_, cpu);
151}
152#endif
153
154#ifndef set_cpu_numa_mem
155static inline void set_cpu_numa_mem(int cpu, int node)
156{
157	per_cpu(_numa_mem_, cpu) = node;
158}
159#endif
160
161#else	/* !CONFIG_HAVE_MEMORYLESS_NODES */
162
163#ifndef numa_mem_id
164/* Returns the number of the nearest Node with memory */
165static inline int numa_mem_id(void)
166{
167	return numa_node_id();
168}
169#endif
170
171#ifndef cpu_to_mem
172static inline int cpu_to_mem(int cpu)
173{
174	return cpu_to_node(cpu);
175}
176#endif
177
178#endif	/* [!]CONFIG_HAVE_MEMORYLESS_NODES */
179
180#if defined(topology_die_id) && defined(topology_die_cpumask)
181#define TOPOLOGY_DIE_SYSFS
182#endif
183#if defined(topology_cluster_id) && defined(topology_cluster_cpumask)
184#define TOPOLOGY_CLUSTER_SYSFS
185#endif
186#if defined(topology_book_id) && defined(topology_book_cpumask)
187#define TOPOLOGY_BOOK_SYSFS
188#endif
189#if defined(topology_drawer_id) && defined(topology_drawer_cpumask)
190#define TOPOLOGY_DRAWER_SYSFS
191#endif
192
193#ifndef topology_physical_package_id
194#define topology_physical_package_id(cpu)	((void)(cpu), -1)
195#endif
196#ifndef topology_die_id
197#define topology_die_id(cpu)			((void)(cpu), -1)
198#endif
199#ifndef topology_cluster_id
200#define topology_cluster_id(cpu)		((void)(cpu), -1)
201#endif
202#ifndef topology_core_id
203#define topology_core_id(cpu)			((void)(cpu), 0)
204#endif
205#ifndef topology_book_id
206#define topology_book_id(cpu)			((void)(cpu), -1)
207#endif
208#ifndef topology_drawer_id
209#define topology_drawer_id(cpu)			((void)(cpu), -1)
210#endif
211#ifndef topology_ppin
212#define topology_ppin(cpu)			((void)(cpu), 0ull)
213#endif
214#ifndef topology_sibling_cpumask
215#define topology_sibling_cpumask(cpu)		cpumask_of(cpu)
216#endif
217#ifndef topology_core_cpumask
218#define topology_core_cpumask(cpu)		cpumask_of(cpu)
219#endif
220#ifndef topology_cluster_cpumask
221#define topology_cluster_cpumask(cpu)		cpumask_of(cpu)
222#endif
223#ifndef topology_die_cpumask
224#define topology_die_cpumask(cpu)		cpumask_of(cpu)
225#endif
226#ifndef topology_book_cpumask
227#define topology_book_cpumask(cpu)		cpumask_of(cpu)
228#endif
229#ifndef topology_drawer_cpumask
230#define topology_drawer_cpumask(cpu)		cpumask_of(cpu)
231#endif
232
233#if defined(CONFIG_SCHED_SMT) && !defined(cpu_smt_mask)
234static inline const struct cpumask *cpu_smt_mask(int cpu)
235{
236	return topology_sibling_cpumask(cpu);
237}
238#endif
239
240#ifndef topology_is_primary_thread
241
242static inline bool topology_is_primary_thread(unsigned int cpu)
243{
244	/*
245	 * When disabling SMT, the primary thread of the SMT will remain
246	 * enabled/active. Architectures that have a special primary thread
247	 * (e.g. x86) need to override this function. Otherwise the first
248	 * thread in the SMT can be made the primary thread.
249	 *
250	 * The sibling cpumask of an offline CPU always contains the CPU
251	 * itself on architectures using the implementation of
252	 * CONFIG_GENERIC_ARCH_TOPOLOGY for building their topology.
253	 * Other architectures not using CONFIG_GENERIC_ARCH_TOPOLOGY for
254	 * building their topology have to check whether to use this default
255	 * implementation or to override it.
256	 */
257	return cpu == cpumask_first(topology_sibling_cpumask(cpu));
258}
259#define topology_is_primary_thread topology_is_primary_thread
260
261#endif
262
263static inline const struct cpumask *cpu_node_mask(int cpu)
264{
265	return cpumask_of_node(cpu_to_node(cpu));
266}
267
268#ifdef CONFIG_NUMA
269int sched_numa_find_nth_cpu(const struct cpumask *cpus, int cpu, int node);
270extern const struct cpumask *sched_numa_hop_mask(unsigned int node, unsigned int hops);
271#else
272static __always_inline int sched_numa_find_nth_cpu(const struct cpumask *cpus, int cpu, int node)
273{
274	return cpumask_nth_and(cpu, cpus, cpu_online_mask);
275}
276
277static inline const struct cpumask *
278sched_numa_hop_mask(unsigned int node, unsigned int hops)
279{
280	return ERR_PTR(-EOPNOTSUPP);
281}
282#endif	/* CONFIG_NUMA */
283
284/**
285 * for_each_node_numadist() - iterate over nodes in increasing distance
286 *			      order, starting from a given node
287 * @node: the iteration variable and the starting node.
288 * @unvisited: a nodemask to keep track of the unvisited nodes.
289 *
290 * This macro iterates over NUMA node IDs in increasing distance from the
291 * starting @node and yields MAX_NUMNODES when all the nodes have been
292 * visited.
293 *
294 * Note that by the time the loop completes, the @unvisited nodemask will
295 * be fully cleared, unless the loop exits early.
296 *
297 * The difference between for_each_node() and for_each_node_numadist() is
298 * that the former allows to iterate over nodes in numerical order, whereas
299 * the latter iterates over nodes in increasing order of distance.
300 *
301 * This complexity of this iterator is O(N^2), where N represents the
302 * number of nodes, as each iteration involves scanning all nodes to
303 * find the one with the shortest distance.
304 *
305 * Requires rcu_lock to be held.
306 */
307#define for_each_node_numadist(node, unvisited)					\
308	for (int __start = (node),						\
309	     (node) = nearest_node_nodemask((__start), &(unvisited));		\
310	     (node) < MAX_NUMNODES;						\
311	     node_clear((node), (unvisited)),					\
312	     (node) = nearest_node_nodemask((__start), &(unvisited)))
313
314/**
315 * for_each_numa_hop_mask - iterate over cpumasks of increasing NUMA distance
316 *                          from a given node.
317 * @mask: the iteration variable.
318 * @node: the NUMA node to start the search from.
319 *
320 * Requires rcu_lock to be held.
321 *
322 * Yields cpu_online_mask for @node == NUMA_NO_NODE.
323 */
324#define for_each_numa_hop_mask(mask, node)				       \
325	for (unsigned int __hops = 0;					       \
326	     mask = (node != NUMA_NO_NODE || __hops) ?			       \
327		     sched_numa_hop_mask(node, __hops) :		       \
328		     cpu_online_mask,					       \
329	     !IS_ERR_OR_NULL(mask);					       \
330	     __hops++)
331
332DECLARE_PER_CPU(unsigned long, cpu_scale);
333
334static inline unsigned long topology_get_cpu_scale(int cpu)
335{
336	return per_cpu(cpu_scale, cpu);
337}
338
339void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity);
340
341#endif /* _LINUX_TOPOLOGY_H */