1 /*
2 * Generic hugetlb support.
3 * (C) William Irwin, April 2004
4 */
5 #include <linux/gfp.h>
6 #include <linux/list.h>
7 #include <linux/init.h>
8 #include <linux/module.h>
9 #include <linux/mm.h>
10 #include <linux/hugetlb.h>
11 #include <linux/sysctl.h>
12 #include <linux/highmem.h>
13 #include <linux/nodemask.h>
14
15 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
16 static unsigned long nr_huge_pages, free_huge_pages;
17 unsigned long max_huge_pages;
18 static struct list_head hugepage_freelists[MAX_NUMNODES];
19 static unsigned int nr_huge_pages_node[MAX_NUMNODES];
20 static unsigned int free_huge_pages_node[MAX_NUMNODES];
21 static DEFINE_SPINLOCK(hugetlb_lock);
22
23 static void enqueue_huge_page(struct page *page)
24 {
25 int nid = page_to_nid(page);
26 list_add(&page->lru, &hugepage_freelists[nid]);
27 free_huge_pages++;
28 free_huge_pages_node[nid]++;
29 }
30
31 static struct page *dequeue_huge_page(void)
32 {
33 int nid = numa_node_id();
34 struct page *page = NULL;
35
36 if (list_empty(&hugepage_freelists[nid])) {
37 for (nid = 0; nid < MAX_NUMNODES; ++nid)
38 if (!list_empty(&hugepage_freelists[nid]))
39 break;
40 }
41 if (nid >= 0 && nid < MAX_NUMNODES &&
42 !list_empty(&hugepage_freelists[nid])) {
43 page = list_entry(hugepage_freelists[nid].next,
44 struct page, lru);
45 list_del(&page->lru);
46 free_huge_pages--;
47 free_huge_pages_node[nid]--;
48 }
49 return page;
50 }
51
52 static struct page *alloc_fresh_huge_page(void)
53 {
54 static int nid = 0;
55 struct page *page;
56 page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN,
57 HUGETLB_PAGE_ORDER);
58 nid = (nid + 1) % num_online_nodes();
59 if (page) {
60 nr_huge_pages++;
61 nr_huge_pages_node[page_to_nid(page)]++;
62 }
63 return page;
64 }
65
66 void free_huge_page(struct page *page)
67 {
68 BUG_ON(page_count(page));
69
70 INIT_LIST_HEAD(&page->lru);
71 page[1].mapping = NULL;
72
73 spin_lock(&hugetlb_lock);
74 enqueue_huge_page(page);
75 spin_unlock(&hugetlb_lock);
76 }
77
78 struct page *alloc_huge_page(void)
79 {
80 struct page *page;
81 int i;
82
83 spin_lock(&hugetlb_lock);
84 page = dequeue_huge_page();
85 if (!page) {
86 spin_unlock(&hugetlb_lock);
87 return NULL;
88 }
89 spin_unlock(&hugetlb_lock);
90 set_page_count(page, 1);
91 page[1].mapping = (void *)free_huge_page;
92 for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); ++i)
93 clear_highpage(&page[i]);
94 return page;
95 }
96
97 static int __init hugetlb_init(void)
98 {
99 unsigned long i;
100 struct page *page;
101
102 for (i = 0; i < MAX_NUMNODES; ++i)
103 INIT_LIST_HEAD(&hugepage_freelists[i]);
104
105 for (i = 0; i < max_huge_pages; ++i) {
106 page = alloc_fresh_huge_page();
107 if (!page)
108 break;
109 spin_lock(&hugetlb_lock);
110 enqueue_huge_page(page);
111 spin_unlock(&hugetlb_lock);
112 }
113 max_huge_pages = free_huge_pages = nr_huge_pages = i;
114 printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
115 return 0;
116 }
117 module_init(hugetlb_init);
118
119 static int __init hugetlb_setup(char *s)
120 {
121 if (sscanf(s, "%lu", &max_huge_pages) <= 0)
122 max_huge_pages = 0;
123 return 1;
124 }
125 __setup("hugepages=", hugetlb_setup);
126
127 #ifdef CONFIG_SYSCTL
128 static void update_and_free_page(struct page *page)
129 {
130 int i;
131 nr_huge_pages--;
132 nr_huge_pages_node[page_zone(page)->zone_pgdat->node_id]--;
133 for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) {
134 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
135 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
136 1 << PG_private | 1<< PG_writeback);
137 set_page_count(&page[i], 0);
138 }
139 set_page_count(page, 1);
140 __free_pages(page, HUGETLB_PAGE_ORDER);
141 }
142
143 #ifdef CONFIG_HIGHMEM
144 static void try_to_free_low(unsigned long count)
145 {
146 int i, nid;
147 for (i = 0; i < MAX_NUMNODES; ++i) {
148 struct page *page, *next;
149 list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
150 if (PageHighMem(page))
151 continue;
152 list_del(&page->lru);
153 update_and_free_page(page);
154 nid = page_zone(page)->zone_pgdat->node_id;
155 free_huge_pages--;
156 free_huge_pages_node[nid]--;
157 if (count >= nr_huge_pages)
158 return;
159 }
160 }
161 }
162 #else
163 static inline void try_to_free_low(unsigned long count)
164 {
165 }
166 #endif
167
168 static unsigned long set_max_huge_pages(unsigned long count)
169 {
170 while (count > nr_huge_pages) {
171 struct page *page = alloc_fresh_huge_page();
172 if (!page)
173 return nr_huge_pages;
174 spin_lock(&hugetlb_lock);
175 enqueue_huge_page(page);
176 spin_unlock(&hugetlb_lock);
177 }
178 if (count >= nr_huge_pages)
179 return nr_huge_pages;
180
181 spin_lock(&hugetlb_lock);
182 try_to_free_low(count);
183 while (count < nr_huge_pages) {
184 struct page *page = dequeue_huge_page();
185 if (!page)
186 break;
187 update_and_free_page(page);
188 }
189 spin_unlock(&hugetlb_lock);
190 return nr_huge_pages;
191 }
192
193 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
194 struct file *file, void __user *buffer,
195 size_t *length, loff_t *ppos)
196 {
197 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
198 max_huge_pages = set_max_huge_pages(max_huge_pages);
199 return 0;
200 }
201 #endif /* CONFIG_SYSCTL */
202
203 int hugetlb_report_meminfo(char *buf)
204 {
205 return sprintf(buf,
206 "HugePages_Total: %5lu\n"
207 "HugePages_Free: %5lu\n"
208 "Hugepagesize: %5lu kB\n",
209 nr_huge_pages,
210 free_huge_pages,
211 HPAGE_SIZE/1024);
212 }
213
214 int hugetlb_report_node_meminfo(int nid, char *buf)
215 {
216 return sprintf(buf,
217 "Node %d HugePages_Total: %5u\n"
218 "Node %d HugePages_Free: %5u\n",
219 nid, nr_huge_pages_node[nid],
220 nid, free_huge_pages_node[nid]);
221 }
222
223 int is_hugepage_mem_enough(size_t size)
224 {
225 return (size + ~HPAGE_MASK)/HPAGE_SIZE <= free_huge_pages;
226 }
227
228 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
229 unsigned long hugetlb_total_pages(void)
230 {
231 return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
232 }
233 EXPORT_SYMBOL(hugetlb_total_pages);
234
235 /*
236 * We cannot handle pagefaults against hugetlb pages at all. They cause
237 * handle_mm_fault() to try to instantiate regular-sized pages in the
238 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
239 * this far.
240 */
241 static struct page *hugetlb_nopage(struct vm_area_struct *vma,
242 unsigned long address, int *unused)
243 {
244 BUG();
245 return NULL;
246 }
247
248 struct vm_operations_struct hugetlb_vm_ops = {
249 .nopage = hugetlb_nopage,
250 };
251
252 void zap_hugepage_range(struct vm_area_struct *vma,
253 unsigned long start, unsigned long length)
254 {
255 struct mm_struct *mm = vma->vm_mm;
256
257 spin_lock(&mm->page_table_lock);
258 unmap_hugepage_range(vma, start, start + length);
259 spin_unlock(&mm->page_table_lock);
260 }
261
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