[PATCH] move m68k rtc drivers over to initcalls
[linux-2.6.git] / mm / hugetlb.c
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/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/nodemask.h>
13 #include <linux/pagemap.h>
14 #include <asm/page.h>
15 #include <asm/pgtable.h>
16
17 #include <linux/hugetlb.h>
18
19 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
20 static unsigned long nr_huge_pages, free_huge_pages;
21 unsigned long max_huge_pages;
22 static struct list_head hugepage_freelists[MAX_NUMNODES];
23 static unsigned int nr_huge_pages_node[MAX_NUMNODES];
24 static unsigned int free_huge_pages_node[MAX_NUMNODES];
25 static DEFINE_SPINLOCK(hugetlb_lock);
26
27 static void enqueue_huge_page(struct page *page)
28 {
29         int nid = page_to_nid(page);
30         list_add(&page->lru, &hugepage_freelists[nid]);
31         free_huge_pages++;
32         free_huge_pages_node[nid]++;
33 }
34
35 static struct page *dequeue_huge_page(void)
36 {
37         int nid = numa_node_id();
38         struct page *page = NULL;
39
40         if (list_empty(&hugepage_freelists[nid])) {
41                 for (nid = 0; nid < MAX_NUMNODES; ++nid)
42                         if (!list_empty(&hugepage_freelists[nid]))
43                                 break;
44         }
45         if (nid >= 0 && nid < MAX_NUMNODES &&
46             !list_empty(&hugepage_freelists[nid])) {
47                 page = list_entry(hugepage_freelists[nid].next,
48                                   struct page, lru);
49                 list_del(&page->lru);
50                 free_huge_pages--;
51                 free_huge_pages_node[nid]--;
52         }
53         return page;
54 }
55
56 static struct page *alloc_fresh_huge_page(void)
57 {
58         static int nid = 0;
59         struct page *page;
60         page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN,
61                                         HUGETLB_PAGE_ORDER);
62         nid = (nid + 1) % num_online_nodes();
63         if (page) {
64                 nr_huge_pages++;
65                 nr_huge_pages_node[page_to_nid(page)]++;
66         }
67         return page;
68 }
69
70 void free_huge_page(struct page *page)
71 {
72         BUG_ON(page_count(page));
73
74         INIT_LIST_HEAD(&page->lru);
75         page[1].mapping = NULL;
76
77         spin_lock(&hugetlb_lock);
78         enqueue_huge_page(page);
79         spin_unlock(&hugetlb_lock);
80 }
81
82 struct page *alloc_huge_page(void)
83 {
84         struct page *page;
85         int i;
86
87         spin_lock(&hugetlb_lock);
88         page = dequeue_huge_page();
89         if (!page) {
90                 spin_unlock(&hugetlb_lock);
91                 return NULL;
92         }
93         spin_unlock(&hugetlb_lock);
94         set_page_count(page, 1);
95         page[1].mapping = (void *)free_huge_page;
96         for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); ++i)
97                 clear_highpage(&page[i]);
98         return page;
99 }
100
101 static int __init hugetlb_init(void)
102 {
103         unsigned long i;
104         struct page *page;
105
106         for (i = 0; i < MAX_NUMNODES; ++i)
107                 INIT_LIST_HEAD(&hugepage_freelists[i]);
108
109         for (i = 0; i < max_huge_pages; ++i) {
110                 page = alloc_fresh_huge_page();
111                 if (!page)
112                         break;
113                 spin_lock(&hugetlb_lock);
114                 enqueue_huge_page(page);
115                 spin_unlock(&hugetlb_lock);
116         }
117         max_huge_pages = free_huge_pages = nr_huge_pages = i;
118         printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
119         return 0;
120 }
121 module_init(hugetlb_init);
122
123 static int __init hugetlb_setup(char *s)
124 {
125         if (sscanf(s, "%lu", &max_huge_pages) <= 0)
126                 max_huge_pages = 0;
127         return 1;
128 }
129 __setup("hugepages=", hugetlb_setup);
130
131 #ifdef CONFIG_SYSCTL
132 static void update_and_free_page(struct page *page)
133 {
134         int i;
135         nr_huge_pages--;
136         nr_huge_pages_node[page_zone(page)->zone_pgdat->node_id]--;
137         for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) {
138                 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
139                                 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
140                                 1 << PG_private | 1<< PG_writeback);
141                 set_page_count(&page[i], 0);
142         }
143         set_page_count(page, 1);
144         __free_pages(page, HUGETLB_PAGE_ORDER);
145 }
146
147 #ifdef CONFIG_HIGHMEM
148 static void try_to_free_low(unsigned long count)
149 {
150         int i, nid;
151         for (i = 0; i < MAX_NUMNODES; ++i) {
152                 struct page *page, *next;
153                 list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
154                         if (PageHighMem(page))
155                                 continue;
156                         list_del(&page->lru);
157                         update_and_free_page(page);
158                         nid = page_zone(page)->zone_pgdat->node_id;
159                         free_huge_pages--;
160                         free_huge_pages_node[nid]--;
161                         if (count >= nr_huge_pages)
162                                 return;
163                 }
164         }
165 }
166 #else
167 static inline void try_to_free_low(unsigned long count)
168 {
169 }
170 #endif
171
172 static unsigned long set_max_huge_pages(unsigned long count)
173 {
174         while (count > nr_huge_pages) {
175                 struct page *page = alloc_fresh_huge_page();
176                 if (!page)
177                         return nr_huge_pages;
178                 spin_lock(&hugetlb_lock);
179                 enqueue_huge_page(page);
180                 spin_unlock(&hugetlb_lock);
181         }
182         if (count >= nr_huge_pages)
183                 return nr_huge_pages;
184
185         spin_lock(&hugetlb_lock);
186         try_to_free_low(count);
187         while (count < nr_huge_pages) {
188                 struct page *page = dequeue_huge_page();
189                 if (!page)
190                         break;
191                 update_and_free_page(page);
192         }
193         spin_unlock(&hugetlb_lock);
194         return nr_huge_pages;
195 }
196
197 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
198                            struct file *file, void __user *buffer,
199                            size_t *length, loff_t *ppos)
200 {
201         proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
202         max_huge_pages = set_max_huge_pages(max_huge_pages);
203         return 0;
204 }
205 #endif /* CONFIG_SYSCTL */
206
207 int hugetlb_report_meminfo(char *buf)
208 {
209         return sprintf(buf,
210                         "HugePages_Total: %5lu\n"
211                         "HugePages_Free:  %5lu\n"
212                         "Hugepagesize:    %5lu kB\n",
213                         nr_huge_pages,
214                         free_huge_pages,
215                         HPAGE_SIZE/1024);
216 }
217
218 int hugetlb_report_node_meminfo(int nid, char *buf)
219 {
220         return sprintf(buf,
221                 "Node %d HugePages_Total: %5u\n"
222                 "Node %d HugePages_Free:  %5u\n",
223                 nid, nr_huge_pages_node[nid],
224                 nid, free_huge_pages_node[nid]);
225 }
226
227 int is_hugepage_mem_enough(size_t size)
228 {
229         return (size + ~HPAGE_MASK)/HPAGE_SIZE <= free_huge_pages;
230 }
231
232 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
233 unsigned long hugetlb_total_pages(void)
234 {
235         return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
236 }
237 EXPORT_SYMBOL(hugetlb_total_pages);
238
239 /*
240  * We cannot handle pagefaults against hugetlb pages at all.  They cause
241  * handle_mm_fault() to try to instantiate regular-sized pages in the
242  * hugegpage VMA.  do_page_fault() is supposed to trap this, so BUG is we get
243  * this far.
244  */
245 static struct page *hugetlb_nopage(struct vm_area_struct *vma,
246                                 unsigned long address, int *unused)
247 {
248         BUG();
249         return NULL;
250 }
251
252 struct vm_operations_struct hugetlb_vm_ops = {
253         .nopage = hugetlb_nopage,
254 };
255
256 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page)
257 {
258         pte_t entry;
259
260         if (vma->vm_flags & VM_WRITE) {
261                 entry =
262                     pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
263         } else {
264                 entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
265         }
266         entry = pte_mkyoung(entry);
267         entry = pte_mkhuge(entry);
268
269         return entry;
270 }
271
272 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
273                             struct vm_area_struct *vma)
274 {
275         pte_t *src_pte, *dst_pte, entry;
276         struct page *ptepage;
277         unsigned long addr = vma->vm_start;
278         unsigned long end = vma->vm_end;
279
280         while (addr < end) {
281                 dst_pte = huge_pte_alloc(dst, addr);
282                 if (!dst_pte)
283                         goto nomem;
284                 src_pte = huge_pte_offset(src, addr);
285                 BUG_ON(!src_pte || pte_none(*src_pte)); /* prefaulted */
286                 entry = *src_pte;
287                 ptepage = pte_page(entry);
288                 get_page(ptepage);
289                 add_mm_counter(dst, rss, HPAGE_SIZE / PAGE_SIZE);
290                 set_huge_pte_at(dst, addr, dst_pte, entry);
291                 addr += HPAGE_SIZE;
292         }
293         return 0;
294
295 nomem:
296         return -ENOMEM;
297 }
298
299 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
300                           unsigned long end)
301 {
302         struct mm_struct *mm = vma->vm_mm;
303         unsigned long address;
304         pte_t *ptep;
305         pte_t pte;
306         struct page *page;
307
308         WARN_ON(!is_vm_hugetlb_page(vma));
309         BUG_ON(start & ~HPAGE_MASK);
310         BUG_ON(end & ~HPAGE_MASK);
311
312         for (address = start; address < end; address += HPAGE_SIZE) {
313                 ptep = huge_pte_offset(mm, address);
314                 if (! ptep)
315                         /* This can happen on truncate, or if an
316                          * mmap() is aborted due to an error before
317                          * the prefault */
318                         continue;
319
320                 pte = huge_ptep_get_and_clear(mm, address, ptep);
321                 if (pte_none(pte))
322                         continue;
323
324                 page = pte_page(pte);
325                 put_page(page);
326         }
327         add_mm_counter(mm, rss,  -((end - start) >> PAGE_SHIFT));
328         flush_tlb_range(vma, start, end);
329 }
330
331 void zap_hugepage_range(struct vm_area_struct *vma,
332                         unsigned long start, unsigned long length)
333 {
334         struct mm_struct *mm = vma->vm_mm;
335
336         spin_lock(&mm->page_table_lock);
337         unmap_hugepage_range(vma, start, start + length);
338         spin_unlock(&mm->page_table_lock);
339 }
340
341 int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
342 {
343         struct mm_struct *mm = current->mm;
344         unsigned long addr;
345         int ret = 0;
346
347         WARN_ON(!is_vm_hugetlb_page(vma));
348         BUG_ON(vma->vm_start & ~HPAGE_MASK);
349         BUG_ON(vma->vm_end & ~HPAGE_MASK);
350
351         hugetlb_prefault_arch_hook(mm);
352
353         spin_lock(&mm->page_table_lock);
354         for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
355                 unsigned long idx;
356                 pte_t *pte = huge_pte_alloc(mm, addr);
357                 struct page *page;
358
359                 if (!pte) {
360                         ret = -ENOMEM;
361                         goto out;
362                 }
363
364                 idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
365                         + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
366                 page = find_get_page(mapping, idx);
367                 if (!page) {
368                         /* charge the fs quota first */
369                         if (hugetlb_get_quota(mapping)) {
370                                 ret = -ENOMEM;
371                                 goto out;
372                         }
373                         page = alloc_huge_page();
374                         if (!page) {
375                                 hugetlb_put_quota(mapping);
376                                 ret = -ENOMEM;
377                                 goto out;
378                         }
379                         ret = add_to_page_cache(page, mapping, idx, GFP_ATOMIC);
380                         if (! ret) {
381                                 unlock_page(page);
382                         } else {
383                                 hugetlb_put_quota(mapping);
384                                 free_huge_page(page);
385                                 goto out;
386                         }
387                 }
388                 add_mm_counter(mm, rss, HPAGE_SIZE / PAGE_SIZE);
389                 set_huge_pte_at(mm, addr, pte, make_huge_pte(vma, page));
390         }
391 out:
392         spin_unlock(&mm->page_table_lock);
393         return ret;
394 }
395
396 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
397                         struct page **pages, struct vm_area_struct **vmas,
398                         unsigned long *position, int *length, int i)
399 {
400         unsigned long vpfn, vaddr = *position;
401         int remainder = *length;
402
403         BUG_ON(!is_vm_hugetlb_page(vma));
404
405         vpfn = vaddr/PAGE_SIZE;
406         while (vaddr < vma->vm_end && remainder) {
407
408                 if (pages) {
409                         pte_t *pte;
410                         struct page *page;
411
412                         /* Some archs (sparc64, sh*) have multiple
413                          * pte_ts to each hugepage.  We have to make
414                          * sure we get the first, for the page
415                          * indexing below to work. */
416                         pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
417
418                         /* hugetlb should be locked, and hence, prefaulted */
419                         WARN_ON(!pte || pte_none(*pte));
420
421                         page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
422
423                         WARN_ON(!PageCompound(page));
424
425                         get_page(page);
426                         pages[i] = page;
427                 }
428
429                 if (vmas)
430                         vmas[i] = vma;
431
432                 vaddr += PAGE_SIZE;
433                 ++vpfn;
434                 --remainder;
435                 ++i;
436         }
437
438         *length = remainder;
439         *position = vaddr;
440
441         return i;
442 }