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>
16 #include <linux/mutex.h>
19 #include <asm/pgtable.h>
21 #include <linux/hugetlb.h>
24 const unsigned long hugetlb_zero
= 0, hugetlb_infinity
= ~0UL;
25 static unsigned long nr_huge_pages
, free_huge_pages
, resv_huge_pages
;
26 static unsigned long surplus_huge_pages
;
27 unsigned long max_huge_pages
;
28 static struct list_head hugepage_freelists
[MAX_NUMNODES
];
29 static unsigned int nr_huge_pages_node
[MAX_NUMNODES
];
30 static unsigned int free_huge_pages_node
[MAX_NUMNODES
];
31 static unsigned int surplus_huge_pages_node
[MAX_NUMNODES
];
32 static gfp_t htlb_alloc_mask
= GFP_HIGHUSER
;
33 unsigned long hugepages_treat_as_movable
;
34 int hugetlb_dynamic_pool
;
37 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
39 static DEFINE_SPINLOCK(hugetlb_lock
);
41 static void clear_huge_page(struct page
*page
, unsigned long addr
)
46 for (i
= 0; i
< (HPAGE_SIZE
/PAGE_SIZE
); i
++) {
48 clear_user_highpage(page
+ i
, addr
+ i
* PAGE_SIZE
);
52 static void copy_huge_page(struct page
*dst
, struct page
*src
,
53 unsigned long addr
, struct vm_area_struct
*vma
)
58 for (i
= 0; i
< HPAGE_SIZE
/PAGE_SIZE
; i
++) {
60 copy_user_highpage(dst
+ i
, src
+ i
, addr
+ i
*PAGE_SIZE
, vma
);
64 static void enqueue_huge_page(struct page
*page
)
66 int nid
= page_to_nid(page
);
67 list_add(&page
->lru
, &hugepage_freelists
[nid
]);
69 free_huge_pages_node
[nid
]++;
72 static struct page
*dequeue_huge_page(struct vm_area_struct
*vma
,
73 unsigned long address
)
76 struct page
*page
= NULL
;
77 struct mempolicy
*mpol
;
78 struct zonelist
*zonelist
= huge_zonelist(vma
, address
,
79 htlb_alloc_mask
, &mpol
);
82 for (z
= zonelist
->zones
; *z
; z
++) {
83 nid
= zone_to_nid(*z
);
84 if (cpuset_zone_allowed_softwall(*z
, htlb_alloc_mask
) &&
85 !list_empty(&hugepage_freelists
[nid
])) {
86 page
= list_entry(hugepage_freelists
[nid
].next
,
90 free_huge_pages_node
[nid
]--;
91 if (vma
&& vma
->vm_flags
& VM_MAYSHARE
)
96 mpol_free(mpol
); /* unref if mpol !NULL */
100 static void update_and_free_page(struct page
*page
)
104 nr_huge_pages_node
[page_to_nid(page
)]--;
105 for (i
= 0; i
< (HPAGE_SIZE
/ PAGE_SIZE
); i
++) {
106 page
[i
].flags
&= ~(1 << PG_locked
| 1 << PG_error
| 1 << PG_referenced
|
107 1 << PG_dirty
| 1 << PG_active
| 1 << PG_reserved
|
108 1 << PG_private
| 1<< PG_writeback
);
110 set_compound_page_dtor(page
, NULL
);
111 set_page_refcounted(page
);
112 __free_pages(page
, HUGETLB_PAGE_ORDER
);
115 static void free_huge_page(struct page
*page
)
117 int nid
= page_to_nid(page
);
119 BUG_ON(page_count(page
));
120 INIT_LIST_HEAD(&page
->lru
);
122 spin_lock(&hugetlb_lock
);
123 if (surplus_huge_pages_node
[nid
]) {
124 update_and_free_page(page
);
125 surplus_huge_pages
--;
126 surplus_huge_pages_node
[nid
]--;
128 enqueue_huge_page(page
);
130 spin_unlock(&hugetlb_lock
);
134 * Increment or decrement surplus_huge_pages. Keep node-specific counters
135 * balanced by operating on them in a round-robin fashion.
136 * Returns 1 if an adjustment was made.
138 static int adjust_pool_surplus(int delta
)
144 VM_BUG_ON(delta
!= -1 && delta
!= 1);
146 nid
= next_node(nid
, node_online_map
);
147 if (nid
== MAX_NUMNODES
)
148 nid
= first_node(node_online_map
);
150 /* To shrink on this node, there must be a surplus page */
151 if (delta
< 0 && !surplus_huge_pages_node
[nid
])
153 /* Surplus cannot exceed the total number of pages */
154 if (delta
> 0 && surplus_huge_pages_node
[nid
] >=
155 nr_huge_pages_node
[nid
])
158 surplus_huge_pages
+= delta
;
159 surplus_huge_pages_node
[nid
] += delta
;
162 } while (nid
!= prev_nid
);
168 static int alloc_fresh_huge_page(void)
175 * Copy static prev_nid to local nid, work on that, then copy it
176 * back to prev_nid afterwards: otherwise there's a window in which
177 * a racer might pass invalid nid MAX_NUMNODES to alloc_pages_node.
178 * But we don't need to use a spin_lock here: it really doesn't
179 * matter if occasionally a racer chooses the same nid as we do.
181 nid
= next_node(prev_nid
, node_online_map
);
182 if (nid
== MAX_NUMNODES
)
183 nid
= first_node(node_online_map
);
186 page
= alloc_pages_node(nid
, htlb_alloc_mask
|__GFP_COMP
|__GFP_NOWARN
,
189 set_compound_page_dtor(page
, free_huge_page
);
190 spin_lock(&hugetlb_lock
);
192 nr_huge_pages_node
[page_to_nid(page
)]++;
193 spin_unlock(&hugetlb_lock
);
194 put_page(page
); /* free it into the hugepage allocator */
200 static struct page
*alloc_buddy_huge_page(struct vm_area_struct
*vma
,
201 unsigned long address
)
205 /* Check if the dynamic pool is enabled */
206 if (!hugetlb_dynamic_pool
)
209 page
= alloc_pages(htlb_alloc_mask
|__GFP_COMP
|__GFP_NOWARN
,
212 set_compound_page_dtor(page
, free_huge_page
);
213 spin_lock(&hugetlb_lock
);
215 nr_huge_pages_node
[page_to_nid(page
)]++;
216 surplus_huge_pages
++;
217 surplus_huge_pages_node
[page_to_nid(page
)]++;
218 spin_unlock(&hugetlb_lock
);
225 * Increase the hugetlb pool such that it can accomodate a reservation
228 static int gather_surplus_pages(int delta
)
230 struct list_head surplus_list
;
231 struct page
*page
, *tmp
;
233 int needed
, allocated
;
235 needed
= (resv_huge_pages
+ delta
) - free_huge_pages
;
240 INIT_LIST_HEAD(&surplus_list
);
244 spin_unlock(&hugetlb_lock
);
245 for (i
= 0; i
< needed
; i
++) {
246 page
= alloc_buddy_huge_page(NULL
, 0);
249 * We were not able to allocate enough pages to
250 * satisfy the entire reservation so we free what
251 * we've allocated so far.
253 spin_lock(&hugetlb_lock
);
258 list_add(&page
->lru
, &surplus_list
);
263 * After retaking hugetlb_lock, we need to recalculate 'needed'
264 * because either resv_huge_pages or free_huge_pages may have changed.
266 spin_lock(&hugetlb_lock
);
267 needed
= (resv_huge_pages
+ delta
) - (free_huge_pages
+ allocated
);
272 * The surplus_list now contains _at_least_ the number of extra pages
273 * needed to accomodate the reservation. Add the appropriate number
274 * of pages to the hugetlb pool and free the extras back to the buddy
280 list_for_each_entry_safe(page
, tmp
, &surplus_list
, lru
) {
281 list_del(&page
->lru
);
283 enqueue_huge_page(page
);
285 update_and_free_page(page
);
292 * When releasing a hugetlb pool reservation, any surplus pages that were
293 * allocated to satisfy the reservation must be explicitly freed if they were
296 void return_unused_surplus_pages(unsigned long unused_resv_pages
)
300 unsigned long nr_pages
;
302 nr_pages
= min(unused_resv_pages
, surplus_huge_pages
);
305 nid
= next_node(nid
, node_online_map
);
306 if (nid
== MAX_NUMNODES
)
307 nid
= first_node(node_online_map
);
309 if (!surplus_huge_pages_node
[nid
])
312 if (!list_empty(&hugepage_freelists
[nid
])) {
313 page
= list_entry(hugepage_freelists
[nid
].next
,
315 list_del(&page
->lru
);
316 update_and_free_page(page
);
318 free_huge_pages_node
[nid
]--;
319 surplus_huge_pages
--;
320 surplus_huge_pages_node
[nid
]--;
326 static struct page
*alloc_huge_page(struct vm_area_struct
*vma
,
329 struct page
*page
= NULL
;
330 int use_reserved_page
= vma
->vm_flags
& VM_MAYSHARE
;
332 spin_lock(&hugetlb_lock
);
333 if (!use_reserved_page
&& (free_huge_pages
<= resv_huge_pages
))
336 page
= dequeue_huge_page(vma
, addr
);
340 spin_unlock(&hugetlb_lock
);
341 set_page_refcounted(page
);
345 spin_unlock(&hugetlb_lock
);
348 * Private mappings do not use reserved huge pages so the allocation
349 * may have failed due to an undersized hugetlb pool. Try to grab a
350 * surplus huge page from the buddy allocator.
352 if (!use_reserved_page
)
353 page
= alloc_buddy_huge_page(vma
, addr
);
358 static int __init
hugetlb_init(void)
362 if (HPAGE_SHIFT
== 0)
365 for (i
= 0; i
< MAX_NUMNODES
; ++i
)
366 INIT_LIST_HEAD(&hugepage_freelists
[i
]);
368 for (i
= 0; i
< max_huge_pages
; ++i
) {
369 if (!alloc_fresh_huge_page())
372 max_huge_pages
= free_huge_pages
= nr_huge_pages
= i
;
373 printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages
);
376 module_init(hugetlb_init
);
378 static int __init
hugetlb_setup(char *s
)
380 if (sscanf(s
, "%lu", &max_huge_pages
) <= 0)
384 __setup("hugepages=", hugetlb_setup
);
386 static unsigned int cpuset_mems_nr(unsigned int *array
)
391 for_each_node_mask(node
, cpuset_current_mems_allowed
)
398 #ifdef CONFIG_HIGHMEM
399 static void try_to_free_low(unsigned long count
)
403 for (i
= 0; i
< MAX_NUMNODES
; ++i
) {
404 struct page
*page
, *next
;
405 list_for_each_entry_safe(page
, next
, &hugepage_freelists
[i
], lru
) {
406 if (PageHighMem(page
))
408 list_del(&page
->lru
);
409 update_and_free_page(page
);
411 free_huge_pages_node
[page_to_nid(page
)]--;
412 if (count
>= nr_huge_pages
)
418 static inline void try_to_free_low(unsigned long count
)
423 #define persistent_huge_pages (nr_huge_pages - surplus_huge_pages)
424 static unsigned long set_max_huge_pages(unsigned long count
)
426 unsigned long min_count
, ret
;
429 * Increase the pool size
430 * First take pages out of surplus state. Then make up the
431 * remaining difference by allocating fresh huge pages.
433 spin_lock(&hugetlb_lock
);
434 while (surplus_huge_pages
&& count
> persistent_huge_pages
) {
435 if (!adjust_pool_surplus(-1))
439 while (count
> persistent_huge_pages
) {
442 * If this allocation races such that we no longer need the
443 * page, free_huge_page will handle it by freeing the page
444 * and reducing the surplus.
446 spin_unlock(&hugetlb_lock
);
447 ret
= alloc_fresh_huge_page();
448 spin_lock(&hugetlb_lock
);
453 if (count
>= persistent_huge_pages
)
457 * Decrease the pool size
458 * First return free pages to the buddy allocator (being careful
459 * to keep enough around to satisfy reservations). Then place
460 * pages into surplus state as needed so the pool will shrink
461 * to the desired size as pages become free.
463 min_count
= max(count
, resv_huge_pages
);
464 try_to_free_low(min_count
);
465 while (min_count
< persistent_huge_pages
) {
466 struct page
*page
= dequeue_huge_page(NULL
, 0);
469 update_and_free_page(page
);
471 while (count
< persistent_huge_pages
) {
472 if (!adjust_pool_surplus(1))
476 ret
= persistent_huge_pages
;
477 spin_unlock(&hugetlb_lock
);
481 int hugetlb_sysctl_handler(struct ctl_table
*table
, int write
,
482 struct file
*file
, void __user
*buffer
,
483 size_t *length
, loff_t
*ppos
)
485 proc_doulongvec_minmax(table
, write
, file
, buffer
, length
, ppos
);
486 max_huge_pages
= set_max_huge_pages(max_huge_pages
);
490 int hugetlb_treat_movable_handler(struct ctl_table
*table
, int write
,
491 struct file
*file
, void __user
*buffer
,
492 size_t *length
, loff_t
*ppos
)
494 proc_dointvec(table
, write
, file
, buffer
, length
, ppos
);
495 if (hugepages_treat_as_movable
)
496 htlb_alloc_mask
= GFP_HIGHUSER_MOVABLE
;
498 htlb_alloc_mask
= GFP_HIGHUSER
;
502 #endif /* CONFIG_SYSCTL */
504 int hugetlb_report_meminfo(char *buf
)
507 "HugePages_Total: %5lu\n"
508 "HugePages_Free: %5lu\n"
509 "HugePages_Rsvd: %5lu\n"
510 "HugePages_Surp: %5lu\n"
511 "Hugepagesize: %5lu kB\n",
519 int hugetlb_report_node_meminfo(int nid
, char *buf
)
522 "Node %d HugePages_Total: %5u\n"
523 "Node %d HugePages_Free: %5u\n",
524 nid
, nr_huge_pages_node
[nid
],
525 nid
, free_huge_pages_node
[nid
]);
528 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
529 unsigned long hugetlb_total_pages(void)
531 return nr_huge_pages
* (HPAGE_SIZE
/ PAGE_SIZE
);
535 * We cannot handle pagefaults against hugetlb pages at all. They cause
536 * handle_mm_fault() to try to instantiate regular-sized pages in the
537 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
540 static int hugetlb_vm_op_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
546 struct vm_operations_struct hugetlb_vm_ops
= {
547 .fault
= hugetlb_vm_op_fault
,
550 static pte_t
make_huge_pte(struct vm_area_struct
*vma
, struct page
*page
,
557 pte_mkwrite(pte_mkdirty(mk_pte(page
, vma
->vm_page_prot
)));
559 entry
= pte_wrprotect(mk_pte(page
, vma
->vm_page_prot
));
561 entry
= pte_mkyoung(entry
);
562 entry
= pte_mkhuge(entry
);
567 static void set_huge_ptep_writable(struct vm_area_struct
*vma
,
568 unsigned long address
, pte_t
*ptep
)
572 entry
= pte_mkwrite(pte_mkdirty(*ptep
));
573 if (ptep_set_access_flags(vma
, address
, ptep
, entry
, 1)) {
574 update_mmu_cache(vma
, address
, entry
);
579 int copy_hugetlb_page_range(struct mm_struct
*dst
, struct mm_struct
*src
,
580 struct vm_area_struct
*vma
)
582 pte_t
*src_pte
, *dst_pte
, entry
;
583 struct page
*ptepage
;
587 cow
= (vma
->vm_flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
589 for (addr
= vma
->vm_start
; addr
< vma
->vm_end
; addr
+= HPAGE_SIZE
) {
590 src_pte
= huge_pte_offset(src
, addr
);
593 dst_pte
= huge_pte_alloc(dst
, addr
);
596 spin_lock(&dst
->page_table_lock
);
597 spin_lock(&src
->page_table_lock
);
598 if (!pte_none(*src_pte
)) {
600 ptep_set_wrprotect(src
, addr
, src_pte
);
602 ptepage
= pte_page(entry
);
604 set_huge_pte_at(dst
, addr
, dst_pte
, entry
);
606 spin_unlock(&src
->page_table_lock
);
607 spin_unlock(&dst
->page_table_lock
);
615 void __unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
618 struct mm_struct
*mm
= vma
->vm_mm
;
619 unsigned long address
;
625 * A page gathering list, protected by per file i_mmap_lock. The
626 * lock is used to avoid list corruption from multiple unmapping
627 * of the same page since we are using page->lru.
629 LIST_HEAD(page_list
);
631 WARN_ON(!is_vm_hugetlb_page(vma
));
632 BUG_ON(start
& ~HPAGE_MASK
);
633 BUG_ON(end
& ~HPAGE_MASK
);
635 spin_lock(&mm
->page_table_lock
);
636 for (address
= start
; address
< end
; address
+= HPAGE_SIZE
) {
637 ptep
= huge_pte_offset(mm
, address
);
641 if (huge_pmd_unshare(mm
, &address
, ptep
))
644 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
648 page
= pte_page(pte
);
650 set_page_dirty(page
);
651 list_add(&page
->lru
, &page_list
);
653 spin_unlock(&mm
->page_table_lock
);
654 flush_tlb_range(vma
, start
, end
);
655 list_for_each_entry_safe(page
, tmp
, &page_list
, lru
) {
656 list_del(&page
->lru
);
661 void unmap_hugepage_range(struct vm_area_struct
*vma
, unsigned long start
,
665 * It is undesirable to test vma->vm_file as it should be non-null
666 * for valid hugetlb area. However, vm_file will be NULL in the error
667 * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails,
668 * do_mmap_pgoff() nullifies vma->vm_file before calling this function
669 * to clean up. Since no pte has actually been setup, it is safe to
670 * do nothing in this case.
673 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
674 __unmap_hugepage_range(vma
, start
, end
);
675 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
679 static int hugetlb_cow(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
680 unsigned long address
, pte_t
*ptep
, pte_t pte
)
682 struct page
*old_page
, *new_page
;
685 old_page
= pte_page(pte
);
687 /* If no-one else is actually using this page, avoid the copy
688 * and just make the page writable */
689 avoidcopy
= (page_count(old_page
) == 1);
691 set_huge_ptep_writable(vma
, address
, ptep
);
695 page_cache_get(old_page
);
696 new_page
= alloc_huge_page(vma
, address
);
699 page_cache_release(old_page
);
703 spin_unlock(&mm
->page_table_lock
);
704 copy_huge_page(new_page
, old_page
, address
, vma
);
705 spin_lock(&mm
->page_table_lock
);
707 ptep
= huge_pte_offset(mm
, address
& HPAGE_MASK
);
708 if (likely(pte_same(*ptep
, pte
))) {
710 set_huge_pte_at(mm
, address
, ptep
,
711 make_huge_pte(vma
, new_page
, 1));
712 /* Make the old page be freed below */
715 page_cache_release(new_page
);
716 page_cache_release(old_page
);
720 static int hugetlb_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
721 unsigned long address
, pte_t
*ptep
, int write_access
)
723 int ret
= VM_FAULT_SIGBUS
;
727 struct address_space
*mapping
;
730 mapping
= vma
->vm_file
->f_mapping
;
731 idx
= ((address
- vma
->vm_start
) >> HPAGE_SHIFT
)
732 + (vma
->vm_pgoff
>> (HPAGE_SHIFT
- PAGE_SHIFT
));
735 * Use page lock to guard against racing truncation
736 * before we get page_table_lock.
739 page
= find_lock_page(mapping
, idx
);
741 size
= i_size_read(mapping
->host
) >> HPAGE_SHIFT
;
744 if (hugetlb_get_quota(mapping
))
746 page
= alloc_huge_page(vma
, address
);
748 hugetlb_put_quota(mapping
);
752 clear_huge_page(page
, address
);
754 if (vma
->vm_flags
& VM_SHARED
) {
757 err
= add_to_page_cache(page
, mapping
, idx
, GFP_KERNEL
);
760 hugetlb_put_quota(mapping
);
769 spin_lock(&mm
->page_table_lock
);
770 size
= i_size_read(mapping
->host
) >> HPAGE_SHIFT
;
775 if (!pte_none(*ptep
))
778 new_pte
= make_huge_pte(vma
, page
, ((vma
->vm_flags
& VM_WRITE
)
779 && (vma
->vm_flags
& VM_SHARED
)));
780 set_huge_pte_at(mm
, address
, ptep
, new_pte
);
782 if (write_access
&& !(vma
->vm_flags
& VM_SHARED
)) {
783 /* Optimization, do the COW without a second fault */
784 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, new_pte
);
787 spin_unlock(&mm
->page_table_lock
);
793 spin_unlock(&mm
->page_table_lock
);
794 hugetlb_put_quota(mapping
);
800 int hugetlb_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
801 unsigned long address
, int write_access
)
806 static DEFINE_MUTEX(hugetlb_instantiation_mutex
);
808 ptep
= huge_pte_alloc(mm
, address
);
813 * Serialize hugepage allocation and instantiation, so that we don't
814 * get spurious allocation failures if two CPUs race to instantiate
815 * the same page in the page cache.
817 mutex_lock(&hugetlb_instantiation_mutex
);
819 if (pte_none(entry
)) {
820 ret
= hugetlb_no_page(mm
, vma
, address
, ptep
, write_access
);
821 mutex_unlock(&hugetlb_instantiation_mutex
);
827 spin_lock(&mm
->page_table_lock
);
828 /* Check for a racing update before calling hugetlb_cow */
829 if (likely(pte_same(entry
, *ptep
)))
830 if (write_access
&& !pte_write(entry
))
831 ret
= hugetlb_cow(mm
, vma
, address
, ptep
, entry
);
832 spin_unlock(&mm
->page_table_lock
);
833 mutex_unlock(&hugetlb_instantiation_mutex
);
838 int follow_hugetlb_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
839 struct page
**pages
, struct vm_area_struct
**vmas
,
840 unsigned long *position
, int *length
, int i
)
842 unsigned long pfn_offset
;
843 unsigned long vaddr
= *position
;
844 int remainder
= *length
;
846 spin_lock(&mm
->page_table_lock
);
847 while (vaddr
< vma
->vm_end
&& remainder
) {
852 * Some archs (sparc64, sh*) have multiple pte_ts to
853 * each hugepage. We have to make * sure we get the
854 * first, for the page indexing below to work.
856 pte
= huge_pte_offset(mm
, vaddr
& HPAGE_MASK
);
858 if (!pte
|| pte_none(*pte
)) {
861 spin_unlock(&mm
->page_table_lock
);
862 ret
= hugetlb_fault(mm
, vma
, vaddr
, 0);
863 spin_lock(&mm
->page_table_lock
);
864 if (!(ret
& VM_FAULT_ERROR
))
873 pfn_offset
= (vaddr
& ~HPAGE_MASK
) >> PAGE_SHIFT
;
874 page
= pte_page(*pte
);
878 pages
[i
] = page
+ pfn_offset
;
888 if (vaddr
< vma
->vm_end
&& remainder
&&
889 pfn_offset
< HPAGE_SIZE
/PAGE_SIZE
) {
891 * We use pfn_offset to avoid touching the pageframes
892 * of this compound page.
897 spin_unlock(&mm
->page_table_lock
);
904 void hugetlb_change_protection(struct vm_area_struct
*vma
,
905 unsigned long address
, unsigned long end
, pgprot_t newprot
)
907 struct mm_struct
*mm
= vma
->vm_mm
;
908 unsigned long start
= address
;
912 BUG_ON(address
>= end
);
913 flush_cache_range(vma
, address
, end
);
915 spin_lock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
916 spin_lock(&mm
->page_table_lock
);
917 for (; address
< end
; address
+= HPAGE_SIZE
) {
918 ptep
= huge_pte_offset(mm
, address
);
921 if (huge_pmd_unshare(mm
, &address
, ptep
))
923 if (!pte_none(*ptep
)) {
924 pte
= huge_ptep_get_and_clear(mm
, address
, ptep
);
925 pte
= pte_mkhuge(pte_modify(pte
, newprot
));
926 set_huge_pte_at(mm
, address
, ptep
, pte
);
929 spin_unlock(&mm
->page_table_lock
);
930 spin_unlock(&vma
->vm_file
->f_mapping
->i_mmap_lock
);
932 flush_tlb_range(vma
, start
, end
);
936 struct list_head link
;
941 static long region_add(struct list_head
*head
, long f
, long t
)
943 struct file_region
*rg
, *nrg
, *trg
;
945 /* Locate the region we are either in or before. */
946 list_for_each_entry(rg
, head
, link
)
950 /* Round our left edge to the current segment if it encloses us. */
954 /* Check for and consume any regions we now overlap with. */
956 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
957 if (&rg
->link
== head
)
962 /* If this area reaches higher then extend our area to
963 * include it completely. If this is not the first area
964 * which we intend to reuse, free it. */
977 static long region_chg(struct list_head
*head
, long f
, long t
)
979 struct file_region
*rg
, *nrg
;
982 /* Locate the region we are before or in. */
983 list_for_each_entry(rg
, head
, link
)
987 /* If we are below the current region then a new region is required.
988 * Subtle, allocate a new region at the position but make it zero
989 * size such that we can guarentee to record the reservation. */
990 if (&rg
->link
== head
|| t
< rg
->from
) {
991 nrg
= kmalloc(sizeof(*nrg
), GFP_KERNEL
);
996 INIT_LIST_HEAD(&nrg
->link
);
997 list_add(&nrg
->link
, rg
->link
.prev
);
1002 /* Round our left edge to the current segment if it encloses us. */
1007 /* Check for and consume any regions we now overlap with. */
1008 list_for_each_entry(rg
, rg
->link
.prev
, link
) {
1009 if (&rg
->link
== head
)
1014 /* We overlap with this area, if it extends futher than
1015 * us then we must extend ourselves. Account for its
1016 * existing reservation. */
1021 chg
-= rg
->to
- rg
->from
;
1026 static long region_truncate(struct list_head
*head
, long end
)
1028 struct file_region
*rg
, *trg
;
1031 /* Locate the region we are either in or before. */
1032 list_for_each_entry(rg
, head
, link
)
1035 if (&rg
->link
== head
)
1038 /* If we are in the middle of a region then adjust it. */
1039 if (end
> rg
->from
) {
1042 rg
= list_entry(rg
->link
.next
, typeof(*rg
), link
);
1045 /* Drop any remaining regions. */
1046 list_for_each_entry_safe(rg
, trg
, rg
->link
.prev
, link
) {
1047 if (&rg
->link
== head
)
1049 chg
+= rg
->to
- rg
->from
;
1050 list_del(&rg
->link
);
1056 static int hugetlb_acct_memory(long delta
)
1060 spin_lock(&hugetlb_lock
);
1062 * When cpuset is configured, it breaks the strict hugetlb page
1063 * reservation as the accounting is done on a global variable. Such
1064 * reservation is completely rubbish in the presence of cpuset because
1065 * the reservation is not checked against page availability for the
1066 * current cpuset. Application can still potentially OOM'ed by kernel
1067 * with lack of free htlb page in cpuset that the task is in.
1068 * Attempt to enforce strict accounting with cpuset is almost
1069 * impossible (or too ugly) because cpuset is too fluid that
1070 * task or memory node can be dynamically moved between cpusets.
1072 * The change of semantics for shared hugetlb mapping with cpuset is
1073 * undesirable. However, in order to preserve some of the semantics,
1074 * we fall back to check against current free page availability as
1075 * a best attempt and hopefully to minimize the impact of changing
1076 * semantics that cpuset has.
1079 if (gather_surplus_pages(delta
) < 0)
1082 if (delta
> cpuset_mems_nr(free_huge_pages_node
))
1087 resv_huge_pages
+= delta
;
1089 return_unused_surplus_pages((unsigned long) -delta
);
1092 spin_unlock(&hugetlb_lock
);
1096 int hugetlb_reserve_pages(struct inode
*inode
, long from
, long to
)
1100 chg
= region_chg(&inode
->i_mapping
->private_list
, from
, to
);
1104 ret
= hugetlb_acct_memory(chg
);
1107 region_add(&inode
->i_mapping
->private_list
, from
, to
);
1111 void hugetlb_unreserve_pages(struct inode
*inode
, long offset
, long freed
)
1113 long chg
= region_truncate(&inode
->i_mapping
->private_list
, offset
);
1114 hugetlb_acct_memory(freed
- chg
);