2 * Generic hugetlb support.
3 * (C) William Irwin, April 2004
6 #include <linux/list.h>
7 #include <linux/init.h>
8 #include <linux/module.h>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/nodemask.h>
13 #include <linux/pagemap.h>
14 #include <linux/mempolicy.h>
15 #include <linux/cpuset.h>
18 #include <asm/pgtable.h>
20 #include <linux/hugetlb.h>
23 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
24 static unsigned long nr_huge_pages
, free_huge_pages
;
25 unsigned long max_huge_pages
;
26 static struct list_head hugepage_freelists
[MAX_NUMNODES
];
27 static unsigned int nr_huge_pages_node
[MAX_NUMNODES
];
28 static unsigned int free_huge_pages_node
[MAX_NUMNODES
];
31 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
33 static DEFINE_SPINLOCK(hugetlb_lock
);
35 static void enqueue_huge_page(struct page
*page
)
37 int nid
= page_to_nid(page
);
38 list_add(&page
->lru
, &hugepage_freelists
[nid
]);
40 free_huge_pages_node
[nid
]++;
43 static struct page
*dequeue_huge_page(struct vm_area_struct
*vma
,
44 unsigned long address
)
46 int nid
= numa_node_id();
47 struct page
*page
= NULL
;
48 struct zonelist
*zonelist
= huge_zonelist(vma
, address
);
51 for (z
= zonelist
->zones
; *z
; z
++) {
52 nid
= (*z
)->zone_pgdat
->node_id
;
53 if (cpuset_zone_allowed(*z
, GFP_HIGHUSER
) &&
54 !list_empty(&hugepage_freelists
[nid
]))
59 page
= list_entry(hugepage_freelists
[nid
].next
,
63 free_huge_pages_node
[nid
]--;
68 static int alloc_fresh_huge_page(void)
72 page
= alloc_pages_node(nid
, GFP_HIGHUSER
|__GFP_COMP
|__GFP_NOWARN
,
74 nid
= (nid
+ 1) % num_online_nodes();
76 page
[1].lru
.next
= (void *)free_huge_page
; /* dtor */
77 spin_lock(&hugetlb_lock
);
79 nr_huge_pages_node
[page_to_nid(page
)]++;
80 spin_unlock(&hugetlb_lock
);
81 put_page(page
); /* free it into the hugepage allocator */
87 void free_huge_page(struct page
*page
)
89 BUG_ON(page_count(page
));
91 INIT_LIST_HEAD(&page
->lru
);
93 spin_lock(&hugetlb_lock
);
94 enqueue_huge_page(page
);
95 spin_unlock(&hugetlb_lock
);
98 struct page
*alloc_huge_page(struct vm_area_struct
*vma
, unsigned long addr
)
103 spin_lock(&hugetlb_lock
);
104 page
= dequeue_huge_page(vma
, addr
);
106 spin_unlock(&hugetlb_lock
);
109 spin_unlock(&hugetlb_lock
);
110 set_page_refcounted(page
);
111 for (i
= 0; i
< (HPAGE_SIZE
/PAGE_SIZE
); ++i
)
112 clear_user_highpage(&page
[i
], addr
);
116 static int __init
hugetlb_init(void)
120 if (HPAGE_SHIFT
== 0)
123 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
124 INIT_LIST_HEAD(&hugepage_freelists
[i
]);
126 for (i
= 0; i
< max_huge_pages
; ++i
) {
127 if (!alloc_fresh_huge_page())
130 max_huge_pages
= free_huge_pages
= nr_huge_pages
= i
;
131 printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages
);
134 module_init(hugetlb_init
);
136 static int __init
hugetlb_setup(char *s
)
138 if (sscanf(s
, "%lu", &max_huge_pages
) <= 0)
142 __setup("hugepages=", hugetlb_setup
);
145 static void update_and_free_page(struct page
*page
)
149 nr_huge_pages_node
[page_zone(page
)->zone_pgdat
->node_id
]--;
150 for (i
= 0; i
< (HPAGE_SIZE
/ PAGE_SIZE
); i
++) {
151 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
| 1 << PG_referenced
|
152 1 << PG_dirty
| 1 << PG_active
| 1 << PG_reserved
|
153 1 << PG_private
| 1<< PG_writeback
);
155 page
[1].lru
.next
= NULL
;
156 set_page_refcounted(page
);
157 __free_pages(page
, HUGETLB_PAGE_ORDER
);
160 #ifdef CONFIG_HIGHMEM
161 static void try_to_free_low(unsigned long count
)
164 for (i
= 0; i
< MAX_NUMNODES
; ++i
) {
165 struct page
*page
, *next
;
166 list_for_each_entry_safe(page
, next
, &hugepage_freelists
[i
], lru
) {
167 if (PageHighMem(page
))
169 list_del(&page
->lru
);
170 update_and_free_page(page
);
171 nid
= page_zone(page
)->zone_pgdat
->node_id
;
173 free_huge_pages_node
[nid
]--;
174 if (count
>= nr_huge_pages
)
180 static inline void try_to_free_low(unsigned long count
)
185 static unsigned long set_max_huge_pages(unsigned long count
)
187 while (count
> nr_huge_pages
) {
188 if (!alloc_fresh_huge_page())
189 return nr_huge_pages
;
191 if (count
>= nr_huge_pages
)
192 return nr_huge_pages
;
194 spin_lock(&hugetlb_lock
);
195 try_to_free_low(count
);
196 while (count
< nr_huge_pages
) {
197 struct page
*page
= dequeue_huge_page(NULL
, 0);
200 update_and_free_page(page
);
202 spin_unlock(&hugetlb_lock
);
203 return nr_huge_pages
;
206 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
207 struct file
*file
, void __user
*buffer
,
208 size_t *length
, loff_t
*ppos
)
210 proc_doulongvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
211 max_huge_pages
= set_max_huge_pages(max_huge_pages
);
214 #endif /* CONFIG_SYSCTL */
216 int hugetlb_report_meminfo(char *buf
)
219 "HugePages_Total: %5lu\n"
220 "HugePages_Free: %5lu\n"
221 "Hugepagesize: %5lu kB\n",
227 int hugetlb_report_node_meminfo(int nid
, char *buf
)
230 "Node %d HugePages_Total: %5u\n"
231 "Node %d HugePages_Free: %5u\n",
232 nid
, nr_huge_pages_node
[nid
],
233 nid
, free_huge_pages_node
[nid
]);
236 int is_hugepage_mem_enough(size_t size
)
238 return (size
+ ~HPAGE_MASK
)/HPAGE_SIZE
<= free_huge_pages
;
241 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
242 unsigned long hugetlb_total_pages(void)
244 return nr_huge_pages
* (HPAGE_SIZE
/ PAGE_SIZE
);
248 * We cannot handle pagefaults against hugetlb pages at all. They cause
249 * handle_mm_fault() to try to instantiate regular-sized pages in the
250 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
253 static struct page
*hugetlb_nopage(struct vm_area_struct
*vma
,
254 unsigned long address
, int *unused
)
260 struct vm_operations_struct hugetlb_vm_ops
= {
261 .nopage
= hugetlb_nopage
,
264 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
271 pte_mkwrite(pte_mkdirty(mk_pte(page
, vma
->vm_page_prot
)));
273 entry
= pte_wrprotect(mk_pte(page
, vma
->vm_page_prot
));
275 entry
= pte_mkyoung(entry
);
276 entry
= pte_mkhuge(entry
);
281 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
282 unsigned long address
, pte_t
*ptep
)
286 entry
= pte_mkwrite(pte_mkdirty(*ptep
));
287 ptep_set_access_flags(vma
, address
, ptep
, entry
, 1);
288 update_mmu_cache(vma
, address
, entry
);
289 lazy_mmu_prot_update(entry
);
293 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
294 struct vm_area_struct
*vma
)
296 pte_t
*src_pte
, *dst_pte
, entry
;
297 struct page
*ptepage
;
301 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
303 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= HPAGE_SIZE
) {
304 src_pte
= huge_pte_offset(src
, addr
);
307 dst_pte
= huge_pte_alloc(dst
, addr
);
310 spin_lock(&dst
->page_table_lock
);
311 spin_lock(&src
->page_table_lock
);
312 if (!pte_none(*src_pte
)) {
314 ptep_set_wrprotect(src
, addr
, src_pte
);
316 ptepage
= pte_page(entry
);
318 add_mm_counter(dst
, file_rss
, HPAGE_SIZE
/ PAGE_SIZE
);
319 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
321 spin_unlock(&src
->page_table_lock
);
322 spin_unlock(&dst
->page_table_lock
);
330 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
333 struct mm_struct
*mm
= vma
->vm_mm
;
334 unsigned long address
;
339 WARN_ON(!is_vm_hugetlb_page(vma
));
340 BUG_ON(start
& ~HPAGE_MASK
);
341 BUG_ON(end
& ~HPAGE_MASK
);
343 spin_lock(&mm
->page_table_lock
);
345 /* Update high watermark before we lower rss */
346 update_hiwater_rss(mm
);
348 for (address
= start
; address
< end
; address
+= HPAGE_SIZE
) {
349 ptep
= huge_pte_offset(mm
, address
);
353 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
357 page
= pte_page(pte
);
359 add_mm_counter(mm
, file_rss
, (int) -(HPAGE_SIZE
/ PAGE_SIZE
));
362 spin_unlock(&mm
->page_table_lock
);
363 flush_tlb_range(vma
, start
, end
);
366 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
367 unsigned long address
, pte_t
*ptep
, pte_t pte
)
369 struct page
*old_page
, *new_page
;
372 old_page
= pte_page(pte
);
374 /* If no-one else is actually using this page, avoid the copy
375 * and just make the page writable */
376 avoidcopy
= (page_count(old_page
) == 1);
378 set_huge_ptep_writable(vma
, address
, ptep
);
379 return VM_FAULT_MINOR
;
382 page_cache_get(old_page
);
383 new_page
= alloc_huge_page(vma
, address
);
386 page_cache_release(old_page
);
390 spin_unlock(&mm
->page_table_lock
);
391 for (i
= 0; i
< HPAGE_SIZE
/PAGE_SIZE
; i
++)
392 copy_user_highpage(new_page
+ i
, old_page
+ i
,
393 address
+ i
*PAGE_SIZE
);
394 spin_lock(&mm
->page_table_lock
);
396 ptep
= huge_pte_offset(mm
, address
& HPAGE_MASK
);
397 if (likely(pte_same(*ptep
, pte
))) {
399 set_huge_pte_at(mm
, address
, ptep
,
400 make_huge_pte(vma
, new_page
, 1));
401 /* Make the old page be freed below */
404 page_cache_release(new_page
);
405 page_cache_release(old_page
);
406 return VM_FAULT_MINOR
;
409 int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
410 unsigned long address
, pte_t
*ptep
, int write_access
)
412 int ret
= VM_FAULT_SIGBUS
;
416 struct address_space
*mapping
;
419 mapping
= vma
->vm_file
->f_mapping
;
420 idx
= ((address
- vma
->vm_start
) >> HPAGE_SHIFT
)
421 + (vma
->vm_pgoff
>> (HPAGE_SHIFT
- PAGE_SHIFT
));
424 * Use page lock to guard against racing truncation
425 * before we get page_table_lock.
428 page
= find_lock_page(mapping
, idx
);
430 if (hugetlb_get_quota(mapping
))
432 page
= alloc_huge_page(vma
, address
);
434 hugetlb_put_quota(mapping
);
439 if (vma
->vm_flags
& VM_SHARED
) {
442 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
445 hugetlb_put_quota(mapping
);
454 spin_lock(&mm
->page_table_lock
);
455 size
= i_size_read(mapping
->host
) >> HPAGE_SHIFT
;
459 ret
= VM_FAULT_MINOR
;
460 if (!pte_none(*ptep
))
463 add_mm_counter(mm
, file_rss
, HPAGE_SIZE
/ PAGE_SIZE
);
464 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
465 && (vma
->vm_flags
& VM_SHARED
)));
466 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
468 if (write_access
&& !(vma
->vm_flags
& VM_SHARED
)) {
469 /* Optimization, do the COW without a second fault */
470 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
);
473 spin_unlock(&mm
->page_table_lock
);
479 spin_unlock(&mm
->page_table_lock
);
480 hugetlb_put_quota(mapping
);
486 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
487 unsigned long address
, int write_access
)
493 ptep
= huge_pte_alloc(mm
, address
);
499 return hugetlb_no_page(mm
, vma
, address
, ptep
, write_access
);
501 ret
= VM_FAULT_MINOR
;
503 spin_lock(&mm
->page_table_lock
);
504 /* Check for a racing update before calling hugetlb_cow */
505 if (likely(pte_same(entry
, *ptep
)))
506 if (write_access
&& !pte_write(entry
))
507 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
);
508 spin_unlock(&mm
->page_table_lock
);
513 int follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
514 struct page
**pages
, struct vm_area_struct
**vmas
,
515 unsigned long *position
, int *length
, int i
)
517 unsigned long vpfn
, vaddr
= *position
;
518 int remainder
= *length
;
520 vpfn
= vaddr
/PAGE_SIZE
;
521 spin_lock(&mm
->page_table_lock
);
522 while (vaddr
< vma
->vm_end
&& remainder
) {
527 * Some archs (sparc64, sh*) have multiple pte_ts to
528 * each hugepage. We have to make * sure we get the
529 * first, for the page indexing below to work.
531 pte
= huge_pte_offset(mm
, vaddr
& HPAGE_MASK
);
533 if (!pte
|| pte_none(*pte
)) {
536 spin_unlock(&mm
->page_table_lock
);
537 ret
= hugetlb_fault(mm
, vma
, vaddr
, 0);
538 spin_lock(&mm
->page_table_lock
);
539 if (ret
== VM_FAULT_MINOR
)
549 page
= &pte_page(*pte
)[vpfn
% (HPAGE_SIZE
/PAGE_SIZE
)];
562 spin_unlock(&mm
->page_table_lock
);
569 void hugetlb_change_protection(struct vm_area_struct
*vma
,
570 unsigned long address
, unsigned long end
, pgprot_t newprot
)
572 struct mm_struct
*mm
= vma
->vm_mm
;
573 unsigned long start
= address
;
577 BUG_ON(address
>= end
);
578 flush_cache_range(vma
, address
, end
);
580 spin_lock(&mm
->page_table_lock
);
581 for (; address
< end
; address
+= HPAGE_SIZE
) {
582 ptep
= huge_pte_offset(mm
, address
);
585 if (!pte_none(*ptep
)) {
586 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
587 pte
= pte_mkhuge(pte_modify(pte
, newprot
));
588 set_huge_pte_at(mm
, address
, ptep
, pte
);
589 lazy_mmu_prot_update(pte
);
592 spin_unlock(&mm
->page_table_lock
);
594 flush_tlb_range(vma
, start
, end
);