numaif.h

 1/* SPDX-License-Identifier: GPL-2.0-only */
 2/* Copyright (C) 2020, Google LLC. */
 3
 4#ifndef SELFTEST_KVM_NUMAIF_H
 5#define SELFTEST_KVM_NUMAIF_H
 6
 7#include <dirent.h>
 8
 9#include <linux/mempolicy.h>
10
11#include "kvm_syscalls.h"
12
13KVM_SYSCALL_DEFINE(get_mempolicy, 5, int *, policy, const unsigned long *, nmask,
14		   unsigned long, maxnode, void *, addr, int, flags);
15
16KVM_SYSCALL_DEFINE(set_mempolicy, 3, int, mode, const unsigned long *, nmask,
17		   unsigned long, maxnode);
18
19KVM_SYSCALL_DEFINE(set_mempolicy_home_node, 4, unsigned long, start,
20		   unsigned long, len, unsigned long, home_node,
21		   unsigned long, flags);
22
23KVM_SYSCALL_DEFINE(migrate_pages, 4, int, pid, unsigned long, maxnode,
24		   const unsigned long *, frommask, const unsigned long *, tomask);
25
26KVM_SYSCALL_DEFINE(move_pages, 6, int, pid, unsigned long, count, void *, pages,
27		   const int *, nodes, int *, status, int, flags);
28
29KVM_SYSCALL_DEFINE(mbind, 6, void *, addr, unsigned long, size, int, mode,
30		   const unsigned long *, nodemask, unsigned long, maxnode,
31		   unsigned int, flags);
32
33static inline int get_max_numa_node(void)
34{
35	struct dirent *de;
36	int max_node = 0;
37	DIR *d;
38
39	/*
40	 * Assume there's a single node if the kernel doesn't support NUMA,
41	 * or if no nodes are found.
42	 */
43	d = opendir("/sys/devices/system/node");
44	if (!d)
45		return 0;
46
47	while ((de = readdir(d)) != NULL) {
48		int node_id;
49		char *endptr;
50
51		if (strncmp(de->d_name, "node", 4) != 0)
52			continue;
53
54		node_id = strtol(de->d_name + 4, &endptr, 10);
55		if (*endptr != '\0')
56			continue;
57
58		if (node_id > max_node)
59			max_node = node_id;
60	}
61	closedir(d);
62
63	return max_node;
64}
65
66static bool is_numa_available(void)
67{
68	/*
69	 * Probe for NUMA by doing a dummy get_mempolicy().  If the syscall
70	 * fails with ENOSYS, then the kernel was built without NUMA support.
71	 * if the syscall fails with EPERM, then the process/user lacks the
72	 * necessary capabilities (CAP_SYS_NICE).
73	 */
74	return !get_mempolicy(NULL, NULL, 0, NULL, 0) ||
75		(errno != ENOSYS && errno != EPERM);
76}
77
78static inline bool is_multi_numa_node_system(void)
79{
80	return is_numa_available() && get_max_numa_node() >= 1;
81}
82
83#endif /* SELFTEST_KVM_NUMAIF_H */