hugetlb_sysctl.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * HugeTLB sysfs interfaces.
  4 * (C) Nadia Yvette Chambers, April 2004
  5 */
  6
  7#include <linux/sysctl.h>
  8
  9#include "hugetlb_internal.h"
 10
 11#ifdef CONFIG_SYSCTL
 12static int proc_hugetlb_doulongvec_minmax(const struct ctl_table *table, int write,
 13					  void *buffer, size_t *length,
 14					  loff_t *ppos, unsigned long *out)
 15{
 16	struct ctl_table dup_table;
 17
 18	/*
 19	 * In order to avoid races with __do_proc_doulongvec_minmax(), we
 20	 * can duplicate the @table and alter the duplicate of it.
 21	 */
 22	dup_table = *table;
 23	dup_table.data = out;
 24
 25	return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
 26}
 27
 28static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
 29			 const struct ctl_table *table, int write,
 30			 void *buffer, size_t *length, loff_t *ppos)
 31{
 32	struct hstate *h = &default_hstate;
 33	unsigned long tmp = h->max_huge_pages;
 34	int ret;
 35
 36	if (!hugepages_supported())
 37		return -EOPNOTSUPP;
 38
 39	ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
 40					     &tmp);
 41	if (ret)
 42		goto out;
 43
 44	if (write)
 45		ret = __nr_hugepages_store_common(obey_mempolicy, h,
 46						  NUMA_NO_NODE, tmp, *length);
 47out:
 48	return ret;
 49}
 50
 51static int hugetlb_sysctl_handler(const struct ctl_table *table, int write,
 52			  void *buffer, size_t *length, loff_t *ppos)
 53{
 54
 55	return hugetlb_sysctl_handler_common(false, table, write,
 56							buffer, length, ppos);
 57}
 58
 59#ifdef CONFIG_NUMA
 60static int hugetlb_mempolicy_sysctl_handler(const struct ctl_table *table, int write,
 61			  void *buffer, size_t *length, loff_t *ppos)
 62{
 63	return hugetlb_sysctl_handler_common(true, table, write,
 64							buffer, length, ppos);
 65}
 66#endif /* CONFIG_NUMA */
 67
 68static int hugetlb_overcommit_handler(const struct ctl_table *table, int write,
 69		void *buffer, size_t *length, loff_t *ppos)
 70{
 71	struct hstate *h = &default_hstate;
 72	unsigned long tmp;
 73	int ret;
 74
 75	if (!hugepages_supported())
 76		return -EOPNOTSUPP;
 77
 78	tmp = h->nr_overcommit_huge_pages;
 79
 80	if (write && hstate_is_gigantic_no_runtime(h))
 81		return -EINVAL;
 82
 83	ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
 84					     &tmp);
 85	if (ret)
 86		goto out;
 87
 88	if (write) {
 89		spin_lock_irq(&hugetlb_lock);
 90		h->nr_overcommit_huge_pages = tmp;
 91		spin_unlock_irq(&hugetlb_lock);
 92	}
 93out:
 94	return ret;
 95}
 96
 97static const struct ctl_table hugetlb_table[] = {
 98	{
 99		.procname	= "nr_hugepages",
100		.data		= NULL,
101		.maxlen		= sizeof(unsigned long),
102		.mode		= 0644,
103		.proc_handler	= hugetlb_sysctl_handler,
104	},
105#ifdef CONFIG_NUMA
106	{
107		.procname       = "nr_hugepages_mempolicy",
108		.data           = NULL,
109		.maxlen         = sizeof(unsigned long),
110		.mode           = 0644,
111		.proc_handler   = &hugetlb_mempolicy_sysctl_handler,
112	},
113#endif
114	{
115		.procname	= "hugetlb_shm_group",
116		.data		= &sysctl_hugetlb_shm_group,
117		.maxlen		= sizeof(gid_t),
118		.mode		= 0644,
119		.proc_handler	= proc_dointvec,
120	},
121	{
122		.procname	= "nr_overcommit_hugepages",
123		.data		= NULL,
124		.maxlen		= sizeof(unsigned long),
125		.mode		= 0644,
126		.proc_handler	= hugetlb_overcommit_handler,
127	},
128};
129
130void __init hugetlb_sysctl_init(void)
131{
132	register_sysctl_init("vm", hugetlb_table);
133}
134#endif /* CONFIG_SYSCTL */