1
2
3
4
5
6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
7
8#include <linux/mm.h>
9#include <linux/sched.h>
10#include <linux/sched/mm.h>
11#include <linux/sched/coredump.h>
12#include <linux/sched/numa_balancing.h>
13#include <linux/highmem.h>
14#include <linux/hugetlb.h>
15#include <linux/mmu_notifier.h>
16#include <linux/rmap.h>
17#include <linux/swap.h>
18#include <linux/shrinker.h>
19#include <linux/mm_inline.h>
20#include <linux/swapops.h>
21#include <linux/dax.h>
22#include <linux/khugepaged.h>
23#include <linux/freezer.h>
24#include <linux/pfn_t.h>
25#include <linux/mman.h>
26#include <linux/memremap.h>
27#include <linux/pagemap.h>
28#include <linux/debugfs.h>
29#include <linux/migrate.h>
30#include <linux/hashtable.h>
31#include <linux/userfaultfd_k.h>
32#include <linux/page_idle.h>
33#include <linux/shmem_fs.h>
34#include <linux/oom.h>
35#include <linux/numa.h>
36#include <linux/page_owner.h>
37
38#include <asm/tlb.h>
39#include <asm/pgalloc.h>
40#include "internal.h"
41
42
43
44
45
46
47
48
49
50unsigned long transparent_hugepage_flags __read_mostly =
51#ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS
52 (1<<TRANSPARENT_HUGEPAGE_FLAG)|
53#endif
54#ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE
55 (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)|
56#endif
57 (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)|
58 (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)|
59 (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
60
61static struct shrinker deferred_split_shrinker;
62
63static atomic_t huge_zero_refcount;
64struct page *huge_zero_page __read_mostly;
65unsigned long huge_zero_pfn __read_mostly = ~0UL;
66
67static inline bool file_thp_enabled(struct vm_area_struct *vma)
68{
69 return transhuge_vma_enabled(vma, vma->vm_flags) && vma->vm_file &&
70 !inode_is_open_for_write(vma->vm_file->f_inode) &&
71 (vma->vm_flags & VM_EXEC);
72}
73
74bool transparent_hugepage_active(struct vm_area_struct *vma)
75{
76
77 unsigned long addr = (vma->vm_end & HPAGE_PMD_MASK) - HPAGE_PMD_SIZE;
78
79 if (!transhuge_vma_suitable(vma, addr))
80 return false;
81 if (vma_is_anonymous(vma))
82 return __transparent_hugepage_enabled(vma);
83 if (vma_is_shmem(vma))
84 return shmem_huge_enabled(vma);
85 if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS))
86 return file_thp_enabled(vma);
87
88 return false;
89}
90
91static bool get_huge_zero_page(void)
92{
93 struct page *zero_page;
94retry:
95 if (likely(atomic_inc_not_zero(&huge_zero_refcount)))
96 return true;
97
98 zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE,
99 HPAGE_PMD_ORDER);
100 if (!zero_page) {
101 count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED);
102 return false;
103 }
104 count_vm_event(THP_ZERO_PAGE_ALLOC);
105 preempt_disable();
106 if (cmpxchg(&huge_zero_page, NULL, zero_page)) {
107 preempt_enable();
108 __free_pages(zero_page, compound_order(zero_page));
109 goto retry;
110 }
111 WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page));
112
113
114 atomic_set(&huge_zero_refcount, 2);
115 preempt_enable();
116 return true;
117}
118
119static void put_huge_zero_page(void)
120{
121
122
123
124
125 BUG_ON(atomic_dec_and_test(&huge_zero_refcount));
126}
127
128struct page *mm_get_huge_zero_page(struct mm_struct *mm)
129{
130 if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags))
131 return READ_ONCE(huge_zero_page);
132
133 if (!get_huge_zero_page())
134 return NULL;
135
136 if (test_and_set_bit(MMF_HUGE_ZERO_PAGE, &mm->flags))
137 put_huge_zero_page();
138
139 return READ_ONCE(huge_zero_page);
140}
141
142void mm_put_huge_zero_page(struct mm_struct *mm)
143{
144 if (test_bit(MMF_HUGE_ZERO_PAGE, &mm->flags))
145 put_huge_zero_page();
146}
147
148static unsigned long shrink_huge_zero_page_count(struct shrinker *shrink,
149 struct shrink_control *sc)
150{
151
152 return atomic_read(&huge_zero_refcount) == 1 ? HPAGE_PMD_NR : 0;
153}
154
155static unsigned long shrink_huge_zero_page_scan(struct shrinker *shrink,
156 struct shrink_control *sc)
157{
158 if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) {
159 struct page *zero_page = xchg(&huge_zero_page, NULL);
160 BUG_ON(zero_page == NULL);
161 WRITE_ONCE(huge_zero_pfn, ~0UL);
162 __free_pages(zero_page, compound_order(zero_page));
163 return HPAGE_PMD_NR;
164 }
165
166 return 0;
167}
168
169static struct shrinker huge_zero_page_shrinker = {
170 .count_objects = shrink_huge_zero_page_count,
171 .scan_objects = shrink_huge_zero_page_scan,
172 .seeks = DEFAULT_SEEKS,
173};
174
175#ifdef CONFIG_SYSFS
176static ssize_t enabled_show(struct kobject *kobj,
177 struct kobj_attribute *attr, char *buf)
178{
179 const char *output;
180
181 if (test_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags))
182 output = "[always] madvise never";
183 else if (test_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
184 &transparent_hugepage_flags))
185 output = "always [madvise] never";
186 else
187 output = "always madvise [never]";
188
189 return sysfs_emit(buf, "%s\n", output);
190}
191
192static ssize_t enabled_store(struct kobject *kobj,
193 struct kobj_attribute *attr,
194 const char *buf, size_t count)
195{
196 ssize_t ret = count;
197
198 if (sysfs_streq(buf, "always")) {
199 clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags);
200 set_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags);
201 } else if (sysfs_streq(buf, "madvise")) {
202 clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags);
203 set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags);
204 } else if (sysfs_streq(buf, "never")) {
205 clear_bit(TRANSPARENT_HUGEPAGE_FLAG, &transparent_hugepage_flags);
206 clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, &transparent_hugepage_flags);
207 } else
208 ret = -EINVAL;
209
210 if (ret > 0) {
211 int err = start_stop_khugepaged();
212 if (err)
213 ret = err;
214 }
215 return ret;
216}
217static struct kobj_attribute enabled_attr =
218 __ATTR(enabled, 0644, enabled_show, enabled_store);
219
220ssize_t single_hugepage_flag_show(struct kobject *kobj,
221 struct kobj_attribute *attr, char *buf,
222 enum transparent_hugepage_flag flag)
223{
224 return sysfs_emit(buf, "%d\n",
225 !!test_bit(flag, &transparent_hugepage_flags));
226}
227
228ssize_t single_hugepage_flag_store(struct kobject *kobj,
229 struct kobj_attribute *attr,
230 const char *buf, size_t count,
231 enum transparent_hugepage_flag flag)
232{
233 unsigned long value;
234 int ret;
235
236 ret = kstrtoul(buf, 10, &value);
237 if (ret < 0)
238 return ret;
239 if (value > 1)
240 return -EINVAL;
241
242 if (value)
243 set_bit(flag, &transparent_hugepage_flags);
244 else
245 clear_bit(flag, &transparent_hugepage_flags);
246
247 return count;
248}
249
250static ssize_t defrag_show(struct kobject *kobj,
251 struct kobj_attribute *attr, char *buf)
252{
253 const char *output;
254
255 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG,
256 &transparent_hugepage_flags))
257 output = "[always] defer defer+madvise madvise never";
258 else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG,
259 &transparent_hugepage_flags))
260 output = "always [defer] defer+madvise madvise never";
261 else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG,
262 &transparent_hugepage_flags))
263 output = "always defer [defer+madvise] madvise never";
264 else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG,
265 &transparent_hugepage_flags))
266 output = "always defer defer+madvise [madvise] never";
267 else
268 output = "always defer defer+madvise madvise [never]";
269
270 return sysfs_emit(buf, "%s\n", output);
271}
272
273static ssize_t defrag_store(struct kobject *kobj,
274 struct kobj_attribute *attr,
275 const char *buf, size_t count)
276{
277 if (sysfs_streq(buf, "always")) {
278 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags);
279 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags);
280 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags);
281 set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
282 } else if (sysfs_streq(buf, "defer+madvise")) {
283 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
284 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags);
285 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags);
286 set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags);
287 } else if (sysfs_streq(buf, "defer")) {
288 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
289 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags);
290 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags);
291 set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags);
292 } else if (sysfs_streq(buf, "madvise")) {
293 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
294 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags);
295 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags);
296 set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags);
297 } else if (sysfs_streq(buf, "never")) {
298 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
299 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags);
300 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags);
301 clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags);
302 } else
303 return -EINVAL;
304
305 return count;
306}
307static struct kobj_attribute defrag_attr =
308 __ATTR(defrag, 0644, defrag_show, defrag_store);
309
310static ssize_t use_zero_page_show(struct kobject *kobj,
311 struct kobj_attribute *attr, char *buf)
312{
313 return single_hugepage_flag_show(kobj, attr, buf,
314 TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
315}
316static ssize_t use_zero_page_store(struct kobject *kobj,
317 struct kobj_attribute *attr, const char *buf, size_t count)
318{
319 return single_hugepage_flag_store(kobj, attr, buf, count,
320 TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG);
321}
322static struct kobj_attribute use_zero_page_attr =
323 __ATTR(use_zero_page, 0644, use_zero_page_show, use_zero_page_store);
324
325static ssize_t hpage_pmd_size_show(struct kobject *kobj,
326 struct kobj_attribute *attr, char *buf)
327{
328 return sysfs_emit(buf, "%lu\n", HPAGE_PMD_SIZE);
329}
330static struct kobj_attribute hpage_pmd_size_attr =
331 __ATTR_RO(hpage_pmd_size);
332
333static struct attribute *hugepage_attr[] = {
334 &enabled_attr.attr,
335 &defrag_attr.attr,
336 &use_zero_page_attr.attr,
337 &hpage_pmd_size_attr.attr,
338#ifdef CONFIG_SHMEM
339 &shmem_enabled_attr.attr,
340#endif
341 NULL,
342};
343
344static const struct attribute_group hugepage_attr_group = {
345 .attrs = hugepage_attr,
346};
347
348static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj)
349{
350 int err;
351
352 *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj);
353 if (unlikely(!*hugepage_kobj)) {
354 pr_err("failed to create transparent hugepage kobject\n");
355 return -ENOMEM;
356 }
357
358 err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group);
359 if (err) {
360 pr_err("failed to register transparent hugepage group\n");
361 goto delete_obj;
362 }
363
364 err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group);
365 if (err) {
366 pr_err("failed to register transparent hugepage group\n");
367 goto remove_hp_group;
368 }
369
370 return 0;
371
372remove_hp_group:
373 sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group);
374delete_obj:
375 kobject_put(*hugepage_kobj);
376 return err;
377}
378
379static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj)
380{
381 sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group);
382 sysfs_remove_group(hugepage_kobj, &hugepage_attr_group);
383 kobject_put(hugepage_kobj);
384}
385#else
386static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj)
387{
388 return 0;
389}
390
391static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj)
392{
393}
394#endif
395
396static int __init hugepage_init(void)
397{
398 int err;
399 struct kobject *hugepage_kobj;
400
401 if (!has_transparent_hugepage()) {
402
403
404
405
406 transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_NEVER_DAX;
407 return -EINVAL;
408 }
409
410
411
412
413 MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER);
414
415
416
417
418 MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER < 2);
419
420 err = hugepage_init_sysfs(&hugepage_kobj);
421 if (err)
422 goto err_sysfs;
423
424 err = khugepaged_init();
425 if (err)
426 goto err_slab;
427
428 err = register_shrinker(&huge_zero_page_shrinker);
429 if (err)
430 goto err_hzp_shrinker;
431 err = register_shrinker(&deferred_split_shrinker);
432 if (err)
433 goto err_split_shrinker;
434
435
436
437
438
439
440 if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) {
441 transparent_hugepage_flags = 0;
442 return 0;
443 }
444
445 err = start_stop_khugepaged();
446 if (err)
447 goto err_khugepaged;
448
449 return 0;
450err_khugepaged:
451 unregister_shrinker(&deferred_split_shrinker);
452err_split_shrinker:
453 unregister_shrinker(&huge_zero_page_shrinker);
454err_hzp_shrinker:
455 khugepaged_destroy();
456err_slab:
457 hugepage_exit_sysfs(hugepage_kobj);
458err_sysfs:
459 return err;
460}
461subsys_initcall(hugepage_init);
462
463static int __init setup_transparent_hugepage(char *str)
464{
465 int ret = 0;
466 if (!str)
467 goto out;
468 if (!strcmp(str, "always")) {
469 set_bit(TRANSPARENT_HUGEPAGE_FLAG,
470 &transparent_hugepage_flags);
471 clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
472 &transparent_hugepage_flags);
473 ret = 1;
474 } else if (!strcmp(str, "madvise")) {
475 clear_bit(TRANSPARENT_HUGEPAGE_FLAG,
476 &transparent_hugepage_flags);
477 set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
478 &transparent_hugepage_flags);
479 ret = 1;
480 } else if (!strcmp(str, "never")) {
481 clear_bit(TRANSPARENT_HUGEPAGE_FLAG,
482 &transparent_hugepage_flags);
483 clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
484 &transparent_hugepage_flags);
485 ret = 1;
486 }
487out:
488 if (!ret)
489 pr_warn("transparent_hugepage= cannot parse, ignored\n");
490 return ret;
491}
492__setup("transparent_hugepage=", setup_transparent_hugepage);
493
494pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
495{
496 if (likely(vma->vm_flags & VM_WRITE))
497 pmd = pmd_mkwrite(pmd);
498 return pmd;
499}
500
501#ifdef CONFIG_MEMCG
502static inline struct deferred_split *get_deferred_split_queue(struct page *page)
503{
504 struct mem_cgroup *memcg = page_memcg(compound_head(page));
505 struct pglist_data *pgdat = NODE_DATA(page_to_nid(page));
506
507 if (memcg)
508 return &memcg->deferred_split_queue;
509 else
510 return &pgdat->deferred_split_queue;
511}
512#else
513static inline struct deferred_split *get_deferred_split_queue(struct page *page)
514{
515 struct pglist_data *pgdat = NODE_DATA(page_to_nid(page));
516
517 return &pgdat->deferred_split_queue;
518}
519#endif
520
521void prep_transhuge_page(struct page *page)
522{
523
524
525
526
527
528 INIT_LIST_HEAD(page_deferred_list(page));
529 set_compound_page_dtor(page, TRANSHUGE_PAGE_DTOR);
530}
531
532bool is_transparent_hugepage(struct page *page)
533{
534 if (!PageCompound(page))
535 return false;
536
537 page = compound_head(page);
538 return is_huge_zero_page(page) ||
539 page[1].compound_dtor == TRANSHUGE_PAGE_DTOR;
540}
541EXPORT_SYMBOL_GPL(is_transparent_hugepage);
542
543static unsigned long __thp_get_unmapped_area(struct file *filp,
544 unsigned long addr, unsigned long len,
545 loff_t off, unsigned long flags, unsigned long size)
546{
547 loff_t off_end = off + len;
548 loff_t off_align = round_up(off, size);
549 unsigned long len_pad, ret;
550
551 if (off_end <= off_align || (off_end - off_align) < size)
552 return 0;
553
554 len_pad = len + size;
555 if (len_pad < len || (off + len_pad) < off)
556 return 0;
557
558 ret = current->mm->get_unmapped_area(filp, addr, len_pad,
559 off >> PAGE_SHIFT, flags);
560
561
562
563
564
565 if (IS_ERR_VALUE(ret))
566 return 0;
567
568
569
570
571
572 if (ret == addr)
573 return addr;
574
575 ret += (off - ret) & (size - 1);
576 return ret;
577}
578
579unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr,
580 unsigned long len, unsigned long pgoff, unsigned long flags)
581{
582 unsigned long ret;
583 loff_t off = (loff_t)pgoff << PAGE_SHIFT;
584
585 if (!IS_DAX(filp->f_mapping->host) || !IS_ENABLED(CONFIG_FS_DAX_PMD))
586 goto out;
587
588 ret = __thp_get_unmapped_area(filp, addr, len, off, flags, PMD_SIZE);
589 if (ret)
590 return ret;
591out:
592 return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
593}
594EXPORT_SYMBOL_GPL(thp_get_unmapped_area);
595
596static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf,
597 struct page *page, gfp_t gfp)
598{
599 struct vm_area_struct *vma = vmf->vma;
600 pgtable_t pgtable;
601 unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
602 vm_fault_t ret = 0;
603
604 VM_BUG_ON_PAGE(!PageCompound(page), page);
605
606 if (mem_cgroup_charge(page, vma->vm_mm, gfp)) {
607 put_page(page);
608 count_vm_event(THP_FAULT_FALLBACK);
609 count_vm_event(THP_FAULT_FALLBACK_CHARGE);
610 return VM_FAULT_FALLBACK;
611 }
612 cgroup_throttle_swaprate(page, gfp);
613
614 pgtable = pte_alloc_one(vma->vm_mm);
615 if (unlikely(!pgtable)) {
616 ret = VM_FAULT_OOM;
617 goto release;
618 }
619
620 clear_huge_page(page, vmf->address, HPAGE_PMD_NR);
621
622
623
624
625
626 __SetPageUptodate(page);
627
628 vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
629 if (unlikely(!pmd_none(*vmf->pmd))) {
630 goto unlock_release;
631 } else {
632 pmd_t entry;
633
634 ret = check_stable_address_space(vma->vm_mm);
635 if (ret)
636 goto unlock_release;
637
638
639 if (userfaultfd_missing(vma)) {
640 spin_unlock(vmf->ptl);
641 put_page(page);
642 pte_free(vma->vm_mm, pgtable);
643 ret = handle_userfault(vmf, VM_UFFD_MISSING);
644 VM_BUG_ON(ret & VM_FAULT_FALLBACK);
645 return ret;
646 }
647
648 entry = mk_huge_pmd(page, vma->vm_page_prot);
649 entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
650 page_add_new_anon_rmap(page, vma, haddr, true);
651 lru_cache_add_inactive_or_unevictable(page, vma);
652 pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable);
653 set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry);
654 update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);
655 add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR);
656 mm_inc_nr_ptes(vma->vm_mm);
657 spin_unlock(vmf->ptl);
658 count_vm_event(THP_FAULT_ALLOC);
659 count_memcg_event_mm(vma->vm_mm, THP_FAULT_ALLOC);
660 }
661
662 return 0;
663unlock_release:
664 spin_unlock(vmf->ptl);
665release:
666 if (pgtable)
667 pte_free(vma->vm_mm, pgtable);
668 put_page(page);
669 return ret;
670
671}
672
673
674
675
676
677
678
679
680
681
682gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma)
683{
684 const bool vma_madvised = vma && (vma->vm_flags & VM_HUGEPAGE);
685
686
687 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags))
688 return GFP_TRANSHUGE | (vma_madvised ? 0 : __GFP_NORETRY);
689
690
691 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags))
692 return GFP_TRANSHUGE_LIGHT | __GFP_KSWAPD_RECLAIM;
693
694
695 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags))
696 return GFP_TRANSHUGE_LIGHT |
697 (vma_madvised ? __GFP_DIRECT_RECLAIM :
698 __GFP_KSWAPD_RECLAIM);
699
700
701 if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags))
702 return GFP_TRANSHUGE_LIGHT |
703 (vma_madvised ? __GFP_DIRECT_RECLAIM : 0);
704
705 return GFP_TRANSHUGE_LIGHT;
706}
707
708
709static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
710 struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd,
711 struct page *zero_page)
712{
713 pmd_t entry;
714 if (!pmd_none(*pmd))
715 return;
716 entry = mk_pmd(zero_page, vma->vm_page_prot);
717 entry = pmd_mkhuge(entry);
718 if (pgtable)
719 pgtable_trans_huge_deposit(mm, pmd, pgtable);
720 set_pmd_at(mm, haddr, pmd, entry);
721 mm_inc_nr_ptes(mm);
722}
723
724vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf)
725{
726 struct vm_area_struct *vma = vmf->vma;
727 gfp_t gfp;
728 struct page *page;
729 unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
730
731 if (!transhuge_vma_suitable(vma, haddr))
732 return VM_FAULT_FALLBACK;
733 if (unlikely(anon_vma_prepare(vma)))
734 return VM_FAULT_OOM;
735 if (unlikely(khugepaged_enter(vma, vma->vm_flags)))
736 return VM_FAULT_OOM;
737 if (!(vmf->flags & FAULT_FLAG_WRITE) &&
738 !mm_forbids_zeropage(vma->vm_mm) &&
739 transparent_hugepage_use_zero_page()) {
740 pgtable_t pgtable;
741 struct page *zero_page;
742 vm_fault_t ret;
743 pgtable = pte_alloc_one(vma->vm_mm);
744 if (unlikely(!pgtable))
745 return VM_FAULT_OOM;
746 zero_page = mm_get_huge_zero_page(vma->vm_mm);
747 if (unlikely(!zero_page)) {
748 pte_free(vma->vm_mm, pgtable);
749 count_vm_event(THP_FAULT_FALLBACK);
750 return VM_FAULT_FALLBACK;
751 }
752 vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
753 ret = 0;
754 if (pmd_none(*vmf->pmd)) {
755 ret = check_stable_address_space(vma->vm_mm);
756 if (ret) {
757 spin_unlock(vmf->ptl);
758 pte_free(vma->vm_mm, pgtable);
759 } else if (userfaultfd_missing(vma)) {
760 spin_unlock(vmf->ptl);
761 pte_free(vma->vm_mm, pgtable);
762 ret = handle_userfault(vmf, VM_UFFD_MISSING);
763 VM_BUG_ON(ret & VM_FAULT_FALLBACK);
764 } else {
765 set_huge_zero_page(pgtable, vma->vm_mm, vma,
766 haddr, vmf->pmd, zero_page);
767 update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);
768 spin_unlock(vmf->ptl);
769 }
770 } else {
771 spin_unlock(vmf->ptl);
772 pte_free(vma->vm_mm, pgtable);
773 }
774 return ret;
775 }
776 gfp = vma_thp_gfp_mask(vma);
777 page = alloc_hugepage_vma(gfp, vma, haddr, HPAGE_PMD_ORDER);
778 if (unlikely(!page)) {
779 count_vm_event(THP_FAULT_FALLBACK);
780 return VM_FAULT_FALLBACK;
781 }
782 prep_transhuge_page(page);
783 return __do_huge_pmd_anonymous_page(vmf, page, gfp);
784}
785
786static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
787 pmd_t *pmd, pfn_t pfn, pgprot_t prot, bool write,
788 pgtable_t pgtable)
789{
790 struct mm_struct *mm = vma->vm_mm;
791 pmd_t entry;
792 spinlock_t *ptl;
793
794 ptl = pmd_lock(mm, pmd);
795 if (!pmd_none(*pmd)) {
796 if (write) {
797 if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) {
798 WARN_ON_ONCE(!is_huge_zero_pmd(*pmd));
799 goto out_unlock;
800 }
801 entry = pmd_mkyoung(*pmd);
802 entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
803 if (pmdp_set_access_flags(vma, addr, pmd, entry, 1))
804 update_mmu_cache_pmd(vma, addr, pmd);
805 }
806
807 goto out_unlock;
808 }
809
810 entry = pmd_mkhuge(pfn_t_pmd(pfn, prot));
811 if (pfn_t_devmap(pfn))
812 entry = pmd_mkdevmap(entry);
813 if (write) {
814 entry = pmd_mkyoung(pmd_mkdirty(entry));
815 entry = maybe_pmd_mkwrite(entry, vma);
816 }
817
818 if (pgtable) {
819 pgtable_trans_huge_deposit(mm, pmd, pgtable);
820 mm_inc_nr_ptes(mm);
821 pgtable = NULL;
822 }
823
824 set_pmd_at(mm, addr, pmd, entry);
825 update_mmu_cache_pmd(vma, addr, pmd);
826
827out_unlock:
828 spin_unlock(ptl);
829 if (pgtable)
830 pte_free(mm, pgtable);
831}
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846vm_fault_t vmf_insert_pfn_pmd_prot(struct vm_fault *vmf, pfn_t pfn,
847 pgprot_t pgprot, bool write)
848{
849 unsigned long addr = vmf->address & PMD_MASK;
850 struct vm_area_struct *vma = vmf->vma;
851 pgtable_t pgtable = NULL;
852
853
854
855
856
857
858 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
859 !pfn_t_devmap(pfn));
860 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
861 (VM_PFNMAP|VM_MIXEDMAP));
862 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
863
864 if (addr < vma->vm_start || addr >= vma->vm_end)
865 return VM_FAULT_SIGBUS;
866
867 if (arch_needs_pgtable_deposit()) {
868 pgtable = pte_alloc_one(vma->vm_mm);
869 if (!pgtable)
870 return VM_FAULT_OOM;
871 }
872
873 track_pfn_insert(vma, &pgprot, pfn);
874
875 insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable);
876 return VM_FAULT_NOPAGE;
877}
878EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd_prot);
879
880#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
881static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma)
882{
883 if (likely(vma->vm_flags & VM_WRITE))
884 pud = pud_mkwrite(pud);
885 return pud;
886}
887
888static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
889 pud_t *pud, pfn_t pfn, pgprot_t prot, bool write)
890{
891 struct mm_struct *mm = vma->vm_mm;
892 pud_t entry;
893 spinlock_t *ptl;
894
895 ptl = pud_lock(mm, pud);
896 if (!pud_none(*pud)) {
897 if (write) {
898 if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) {
899 WARN_ON_ONCE(!is_huge_zero_pud(*pud));
900 goto out_unlock;
901 }
902 entry = pud_mkyoung(*pud);
903 entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma);
904 if (pudp_set_access_flags(vma, addr, pud, entry, 1))
905 update_mmu_cache_pud(vma, addr, pud);
906 }
907 goto out_unlock;
908 }
909
910 entry = pud_mkhuge(pfn_t_pud(pfn, prot));
911 if (pfn_t_devmap(pfn))
912 entry = pud_mkdevmap(entry);
913 if (write) {
914 entry = pud_mkyoung(pud_mkdirty(entry));
915 entry = maybe_pud_mkwrite(entry, vma);
916 }
917 set_pud_at(mm, addr, pud, entry);
918 update_mmu_cache_pud(vma, addr, pud);
919
920out_unlock:
921 spin_unlock(ptl);
922}
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937vm_fault_t vmf_insert_pfn_pud_prot(struct vm_fault *vmf, pfn_t pfn,
938 pgprot_t pgprot, bool write)
939{
940 unsigned long addr = vmf->address & PUD_MASK;
941 struct vm_area_struct *vma = vmf->vma;
942
943
944
945
946
947
948 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
949 !pfn_t_devmap(pfn));
950 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
951 (VM_PFNMAP|VM_MIXEDMAP));
952 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
953
954 if (addr < vma->vm_start || addr >= vma->vm_end)
955 return VM_FAULT_SIGBUS;
956
957 track_pfn_insert(vma, &pgprot, pfn);
958
959 insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write);
960 return VM_FAULT_NOPAGE;
961}
962EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud_prot);
963#endif
964
965static void touch_pmd(struct vm_area_struct *vma, unsigned long addr,
966 pmd_t *pmd, int flags)
967{
968 pmd_t _pmd;
969
970 _pmd = pmd_mkyoung(*pmd);
971 if (flags & FOLL_WRITE)
972 _pmd = pmd_mkdirty(_pmd);
973 if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK,
974 pmd, _pmd, flags & FOLL_WRITE))
975 update_mmu_cache_pmd(vma, addr, pmd);
976}
977
978struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
979 pmd_t *pmd, int flags, struct dev_pagemap **pgmap)
980{
981 unsigned long pfn = pmd_pfn(*pmd);
982 struct mm_struct *mm = vma->vm_mm;
983 struct page *page;
984
985 assert_spin_locked(pmd_lockptr(mm, pmd));
986
987
988
989
990
991 WARN_ONCE(flags & FOLL_COW, "mm: In follow_devmap_pmd with FOLL_COW set");
992
993
994 if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
995 (FOLL_PIN | FOLL_GET)))
996 return NULL;
997
998 if (flags & FOLL_WRITE && !pmd_write(*pmd))
999 return NULL;
1000
1001 if (pmd_present(*pmd) && pmd_devmap(*pmd))
1002 ;
1003 else
1004 return NULL;
1005
1006 if (flags & FOLL_TOUCH)
1007 touch_pmd(vma, addr, pmd, flags);
1008
1009
1010
1011
1012
1013 if (!(flags & (FOLL_GET | FOLL_PIN)))
1014 return ERR_PTR(-EEXIST);
1015
1016 pfn += (addr & ~PMD_MASK) >> PAGE_SHIFT;
1017 *pgmap = get_dev_pagemap(pfn, *pgmap);
1018 if (!*pgmap)
1019 return ERR_PTR(-EFAULT);
1020 page = pfn_to_page(pfn);
1021 if (!try_grab_page(page, flags))
1022 page = ERR_PTR(-ENOMEM);
1023
1024 return page;
1025}
1026
1027int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
1028 pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,
1029 struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma)
1030{
1031 spinlock_t *dst_ptl, *src_ptl;
1032 struct page *src_page;
1033 pmd_t pmd;
1034 pgtable_t pgtable = NULL;
1035 int ret = -ENOMEM;
1036
1037
1038 if (!vma_is_anonymous(dst_vma))
1039 return 0;
1040
1041 pgtable = pte_alloc_one(dst_mm);
1042 if (unlikely(!pgtable))
1043 goto out;
1044
1045 dst_ptl = pmd_lock(dst_mm, dst_pmd);
1046 src_ptl = pmd_lockptr(src_mm, src_pmd);
1047 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
1048
1049 ret = -EAGAIN;
1050 pmd = *src_pmd;
1051
1052#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
1053 if (unlikely(is_swap_pmd(pmd))) {
1054 swp_entry_t entry = pmd_to_swp_entry(pmd);
1055
1056 VM_BUG_ON(!is_pmd_migration_entry(pmd));
1057 if (is_writable_migration_entry(entry)) {
1058 entry = make_readable_migration_entry(
1059 swp_offset(entry));
1060 pmd = swp_entry_to_pmd(entry);
1061 if (pmd_swp_soft_dirty(*src_pmd))
1062 pmd = pmd_swp_mksoft_dirty(pmd);
1063 if (pmd_swp_uffd_wp(*src_pmd))
1064 pmd = pmd_swp_mkuffd_wp(pmd);
1065 set_pmd_at(src_mm, addr, src_pmd, pmd);
1066 }
1067 add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR);
1068 mm_inc_nr_ptes(dst_mm);
1069 pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable);
1070 if (!userfaultfd_wp(dst_vma))
1071 pmd = pmd_swp_clear_uffd_wp(pmd);
1072 set_pmd_at(dst_mm, addr, dst_pmd, pmd);
1073 ret = 0;
1074 goto out_unlock;
1075 }
1076#endif
1077
1078 if (unlikely(!pmd_trans_huge(pmd))) {
1079 pte_free(dst_mm, pgtable);
1080 goto out_unlock;
1081 }
1082
1083
1084
1085
1086
1087 if (is_huge_zero_pmd(pmd)) {
1088
1089
1090
1091
1092
1093 mm_get_huge_zero_page(dst_mm);
1094 goto out_zero_page;
1095 }
1096
1097 src_page = pmd_page(pmd);
1098 VM_BUG_ON_PAGE(!PageHead(src_page), src_page);
1099
1100
1101
1102
1103
1104
1105
1106
1107 if (unlikely(page_needs_cow_for_dma(src_vma, src_page))) {
1108 pte_free(dst_mm, pgtable);
1109 spin_unlock(src_ptl);
1110 spin_unlock(dst_ptl);
1111 __split_huge_pmd(src_vma, src_pmd, addr, false, NULL);
1112 return -EAGAIN;
1113 }
1114
1115 get_page(src_page);
1116 page_dup_rmap(src_page, true);
1117 add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR);
1118out_zero_page:
1119 mm_inc_nr_ptes(dst_mm);
1120 pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable);
1121 pmdp_set_wrprotect(src_mm, addr, src_pmd);
1122 if (!userfaultfd_wp(dst_vma))
1123 pmd = pmd_clear_uffd_wp(pmd);
1124 pmd = pmd_mkold(pmd_wrprotect(pmd));
1125 set_pmd_at(dst_mm, addr, dst_pmd, pmd);
1126
1127 ret = 0;
1128out_unlock:
1129 spin_unlock(src_ptl);
1130 spin_unlock(dst_ptl);
1131out:
1132 return ret;
1133}
1134
1135#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
1136static void touch_pud(struct vm_area_struct *vma, unsigned long addr,
1137 pud_t *pud, int flags)
1138{
1139 pud_t _pud;
1140
1141 _pud = pud_mkyoung(*pud);
1142 if (flags & FOLL_WRITE)
1143 _pud = pud_mkdirty(_pud);
1144 if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK,
1145 pud, _pud, flags & FOLL_WRITE))
1146 update_mmu_cache_pud(vma, addr, pud);
1147}
1148
1149struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr,
1150 pud_t *pud, int flags, struct dev_pagemap **pgmap)
1151{
1152 unsigned long pfn = pud_pfn(*pud);
1153 struct mm_struct *mm = vma->vm_mm;
1154 struct page *page;
1155
1156 assert_spin_locked(pud_lockptr(mm, pud));
1157
1158 if (flags & FOLL_WRITE && !pud_write(*pud))
1159 return NULL;
1160
1161
1162 if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
1163 (FOLL_PIN | FOLL_GET)))
1164 return NULL;
1165
1166 if (pud_present(*pud) && pud_devmap(*pud))
1167 ;
1168 else
1169 return NULL;
1170
1171 if (flags & FOLL_TOUCH)
1172 touch_pud(vma, addr, pud, flags);
1173
1174
1175
1176
1177
1178
1179
1180 if (!(flags & (FOLL_GET | FOLL_PIN)))
1181 return ERR_PTR(-EEXIST);
1182
1183 pfn += (addr & ~PUD_MASK) >> PAGE_SHIFT;
1184 *pgmap = get_dev_pagemap(pfn, *pgmap);
1185 if (!*pgmap)
1186 return ERR_PTR(-EFAULT);
1187 page = pfn_to_page(pfn);
1188 if (!try_grab_page(page, flags))
1189 page = ERR_PTR(-ENOMEM);
1190
1191 return page;
1192}
1193
1194int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm,
1195 pud_t *dst_pud, pud_t *src_pud, unsigned long addr,
1196 struct vm_area_struct *vma)
1197{
1198 spinlock_t *dst_ptl, *src_ptl;
1199 pud_t pud;
1200 int ret;
1201
1202 dst_ptl = pud_lock(dst_mm, dst_pud);
1203 src_ptl = pud_lockptr(src_mm, src_pud);
1204 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
1205
1206 ret = -EAGAIN;
1207 pud = *src_pud;
1208 if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud)))
1209 goto out_unlock;
1210
1211
1212
1213
1214
1215
1216 if (is_huge_zero_pud(pud)) {
1217
1218 }
1219
1220
1221 if (unlikely(page_needs_cow_for_dma(vma, pud_page(pud)))) {
1222 spin_unlock(src_ptl);
1223 spin_unlock(dst_ptl);
1224 __split_huge_pud(vma, src_pud, addr);
1225 return -EAGAIN;
1226 }
1227
1228 pudp_set_wrprotect(src_mm, addr, src_pud);
1229 pud = pud_mkold(pud_wrprotect(pud));
1230 set_pud_at(dst_mm, addr, dst_pud, pud);
1231
1232 ret = 0;
1233out_unlock:
1234 spin_unlock(src_ptl);
1235 spin_unlock(dst_ptl);
1236 return ret;
1237}
1238
1239void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud)
1240{
1241 pud_t entry;
1242 unsigned long haddr;
1243 bool write = vmf->flags & FAULT_FLAG_WRITE;
1244
1245 vmf->ptl = pud_lock(vmf->vma->vm_mm, vmf->pud);
1246 if (unlikely(!pud_same(*vmf->pud, orig_pud)))
1247 goto unlock;
1248
1249 entry = pud_mkyoung(orig_pud);
1250 if (write)
1251 entry = pud_mkdirty(entry);
1252 haddr = vmf->address & HPAGE_PUD_MASK;
1253 if (pudp_set_access_flags(vmf->vma, haddr, vmf->pud, entry, write))
1254 update_mmu_cache_pud(vmf->vma, vmf->address, vmf->pud);
1255
1256unlock:
1257 spin_unlock(vmf->ptl);
1258}
1259#endif
1260
1261void huge_pmd_set_accessed(struct vm_fault *vmf)
1262{
1263 pmd_t entry;
1264 unsigned long haddr;
1265 bool write = vmf->flags & FAULT_FLAG_WRITE;
1266 pmd_t orig_pmd = vmf->orig_pmd;
1267
1268 vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd);
1269 if (unlikely(!pmd_same(*vmf->pmd, orig_pmd)))
1270 goto unlock;
1271
1272 entry = pmd_mkyoung(orig_pmd);
1273 if (write)
1274 entry = pmd_mkdirty(entry);
1275 haddr = vmf->address & HPAGE_PMD_MASK;
1276 if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write))
1277 update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd);
1278
1279unlock:
1280 spin_unlock(vmf->ptl);
1281}
1282
1283vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf)
1284{
1285 struct vm_area_struct *vma = vmf->vma;
1286 struct page *page;
1287 unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
1288 pmd_t orig_pmd = vmf->orig_pmd;
1289
1290 vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd);
1291 VM_BUG_ON_VMA(!vma->anon_vma, vma);
1292
1293 if (is_huge_zero_pmd(orig_pmd))
1294 goto fallback;
1295
1296 spin_lock(vmf->ptl);
1297
1298 if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) {
1299 spin_unlock(vmf->ptl);
1300 return 0;
1301 }
1302
1303 page = pmd_page(orig_pmd);
1304 VM_BUG_ON_PAGE(!PageHead(page), page);
1305
1306
1307 if (!trylock_page(page)) {
1308 get_page(page);
1309 spin_unlock(vmf->ptl);
1310 lock_page(page);
1311 spin_lock(vmf->ptl);
1312 if (unlikely(!pmd_same(*vmf->pmd, orig_pmd))) {
1313 spin_unlock(vmf->ptl);
1314 unlock_page(page);
1315 put_page(page);
1316 return 0;
1317 }
1318 put_page(page);
1319 }
1320
1321
1322
1323
1324
1325 if (reuse_swap_page(page, NULL)) {
1326 pmd_t entry;
1327 entry = pmd_mkyoung(orig_pmd);
1328 entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
1329 if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1))
1330 update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);
1331 unlock_page(page);
1332 spin_unlock(vmf->ptl);
1333 return VM_FAULT_WRITE;
1334 }
1335
1336 unlock_page(page);
1337 spin_unlock(vmf->ptl);
1338fallback:
1339 __split_huge_pmd(vma, vmf->pmd, vmf->address, false, NULL);
1340 return VM_FAULT_FALLBACK;
1341}
1342
1343
1344
1345
1346
1347static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags)
1348{
1349 return pmd_write(pmd) ||
1350 ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd));
1351}
1352
1353struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
1354 unsigned long addr,
1355 pmd_t *pmd,
1356 unsigned int flags)
1357{
1358 struct mm_struct *mm = vma->vm_mm;
1359 struct page *page = NULL;
1360
1361 assert_spin_locked(pmd_lockptr(mm, pmd));
1362
1363 if (flags & FOLL_WRITE && !can_follow_write_pmd(*pmd, flags))
1364 goto out;
1365
1366
1367 if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd))
1368 return ERR_PTR(-EFAULT);
1369
1370
1371 if ((flags & FOLL_NUMA) && pmd_protnone(*pmd))
1372 goto out;
1373
1374 page = pmd_page(*pmd);
1375 VM_BUG_ON_PAGE(!PageHead(page) && !is_zone_device_page(page), page);
1376
1377 if (!try_grab_page(page, flags))
1378 return ERR_PTR(-ENOMEM);
1379
1380 if (flags & FOLL_TOUCH)
1381 touch_pmd(vma, addr, pmd, flags);
1382
1383 if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405 if (PageAnon(page) && compound_mapcount(page) != 1)
1406 goto skip_mlock;
1407 if (PageDoubleMap(page) || !page->mapping)
1408 goto skip_mlock;
1409 if (!trylock_page(page))
1410 goto skip_mlock;
1411 if (page->mapping && !PageDoubleMap(page))
1412 mlock_vma_page(page);
1413 unlock_page(page);
1414 }
1415skip_mlock:
1416 page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT;
1417 VM_BUG_ON_PAGE(!PageCompound(page) && !is_zone_device_page(page), page);
1418
1419out:
1420 return page;
1421}
1422
1423
1424vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf)
1425{
1426 struct vm_area_struct *vma = vmf->vma;
1427 pmd_t oldpmd = vmf->orig_pmd;
1428 pmd_t pmd;
1429 struct page *page;
1430 unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
1431 int page_nid = NUMA_NO_NODE;
1432 int target_nid, last_cpupid = -1;
1433 bool migrated = false;
1434 bool was_writable = pmd_savedwrite(oldpmd);
1435 int flags = 0;
1436
1437 vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
1438 if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) {
1439 spin_unlock(vmf->ptl);
1440 goto out;
1441 }
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454 if (mm_tlb_flush_pending(vma->vm_mm)) {
1455 flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE);
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465 mmu_notifier_invalidate_range(vma->vm_mm, haddr,
1466 haddr + HPAGE_PMD_SIZE);
1467 }
1468
1469 pmd = pmd_modify(oldpmd, vma->vm_page_prot);
1470 page = vm_normal_page_pmd(vma, haddr, pmd);
1471 if (!page)
1472 goto out_map;
1473
1474
1475 if (!was_writable)
1476 flags |= TNF_NO_GROUP;
1477
1478 page_nid = page_to_nid(page);
1479 last_cpupid = page_cpupid_last(page);
1480 target_nid = numa_migrate_prep(page, vma, haddr, page_nid,
1481 &flags);
1482
1483 if (target_nid == NUMA_NO_NODE) {
1484 put_page(page);
1485 goto out_map;
1486 }
1487
1488 spin_unlock(vmf->ptl);
1489
1490 migrated = migrate_misplaced_page(page, vma, target_nid);
1491 if (migrated) {
1492 flags |= TNF_MIGRATED;
1493 page_nid = target_nid;
1494 } else {
1495 flags |= TNF_MIGRATE_FAIL;
1496 vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
1497 if (unlikely(!pmd_same(oldpmd, *vmf->pmd))) {
1498 spin_unlock(vmf->ptl);
1499 goto out;
1500 }
1501 goto out_map;
1502 }
1503
1504out:
1505 if (page_nid != NUMA_NO_NODE)
1506 task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR,
1507 flags);
1508
1509 return 0;
1510
1511out_map:
1512
1513 pmd = pmd_modify(oldpmd, vma->vm_page_prot);
1514 pmd = pmd_mkyoung(pmd);
1515 if (was_writable)
1516 pmd = pmd_mkwrite(pmd);
1517 set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd);
1518 update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);
1519 spin_unlock(vmf->ptl);
1520 goto out;
1521}
1522
1523
1524
1525
1526
1527bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
1528 pmd_t *pmd, unsigned long addr, unsigned long next)
1529{
1530 spinlock_t *ptl;
1531 pmd_t orig_pmd;
1532 struct page *page;
1533 struct mm_struct *mm = tlb->mm;
1534 bool ret = false;
1535
1536 tlb_change_page_size(tlb, HPAGE_PMD_SIZE);
1537
1538 ptl = pmd_trans_huge_lock(pmd, vma);
1539 if (!ptl)
1540 goto out_unlocked;
1541
1542 orig_pmd = *pmd;
1543 if (is_huge_zero_pmd(orig_pmd))
1544 goto out;
1545
1546 if (unlikely(!pmd_present(orig_pmd))) {
1547 VM_BUG_ON(thp_migration_supported() &&
1548 !is_pmd_migration_entry(orig_pmd));
1549 goto out;
1550 }
1551
1552 page = pmd_page(orig_pmd);
1553
1554
1555
1556
1557 if (total_mapcount(page) != 1)
1558 goto out;
1559
1560 if (!trylock_page(page))
1561 goto out;
1562
1563
1564
1565
1566
1567 if (next - addr != HPAGE_PMD_SIZE) {
1568 get_page(page);
1569 spin_unlock(ptl);
1570 split_huge_page(page);
1571 unlock_page(page);
1572 put_page(page);
1573 goto out_unlocked;
1574 }
1575
1576 if (PageDirty(page))
1577 ClearPageDirty(page);
1578 unlock_page(page);
1579
1580 if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) {
1581 pmdp_invalidate(vma, addr, pmd);
1582 orig_pmd = pmd_mkold(orig_pmd);
1583 orig_pmd = pmd_mkclean(orig_pmd);
1584
1585 set_pmd_at(mm, addr, pmd, orig_pmd);
1586 tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
1587 }
1588
1589 mark_page_lazyfree(page);
1590 ret = true;
1591out:
1592 spin_unlock(ptl);
1593out_unlocked:
1594 return ret;
1595}
1596
1597static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd)
1598{
1599 pgtable_t pgtable;
1600
1601 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
1602 pte_free(mm, pgtable);
1603 mm_dec_nr_ptes(mm);
1604}
1605
1606int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
1607 pmd_t *pmd, unsigned long addr)
1608{
1609 pmd_t orig_pmd;
1610 spinlock_t *ptl;
1611
1612 tlb_change_page_size(tlb, HPAGE_PMD_SIZE);
1613
1614 ptl = __pmd_trans_huge_lock(pmd, vma);
1615 if (!ptl)
1616 return 0;
1617
1618
1619
1620
1621
1622
1623 orig_pmd = pmdp_huge_get_and_clear_full(vma, addr, pmd,
1624 tlb->fullmm);
1625 tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
1626 if (vma_is_special_huge(vma)) {
1627 if (arch_needs_pgtable_deposit())
1628 zap_deposited_table(tlb->mm, pmd);
1629 spin_unlock(ptl);
1630 } else if (is_huge_zero_pmd(orig_pmd)) {
1631 zap_deposited_table(tlb->mm, pmd);
1632 spin_unlock(ptl);
1633 } else {
1634 struct page *page = NULL;
1635 int flush_needed = 1;
1636
1637 if (pmd_present(orig_pmd)) {
1638 page = pmd_page(orig_pmd);
1639 page_remove_rmap(page, true);
1640 VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
1641 VM_BUG_ON_PAGE(!PageHead(page), page);
1642 } else if (thp_migration_supported()) {
1643 swp_entry_t entry;
1644
1645 VM_BUG_ON(!is_pmd_migration_entry(orig_pmd));
1646 entry = pmd_to_swp_entry(orig_pmd);
1647 page = pfn_swap_entry_to_page(entry);
1648 flush_needed = 0;
1649 } else
1650 WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!");
1651
1652 if (PageAnon(page)) {
1653 zap_deposited_table(tlb->mm, pmd);
1654 add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
1655 } else {
1656 if (arch_needs_pgtable_deposit())
1657 zap_deposited_table(tlb->mm, pmd);
1658 add_mm_counter(tlb->mm, mm_counter_file(page), -HPAGE_PMD_NR);
1659 }
1660
1661 spin_unlock(ptl);
1662 if (flush_needed)
1663 tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE);
1664 }
1665 return 1;
1666}
1667
1668#ifndef pmd_move_must_withdraw
1669static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl,
1670 spinlock_t *old_pmd_ptl,
1671 struct vm_area_struct *vma)
1672{
1673
1674
1675
1676
1677
1678
1679 return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma);
1680}
1681#endif
1682
1683static pmd_t move_soft_dirty_pmd(pmd_t pmd)
1684{
1685#ifdef CONFIG_MEM_SOFT_DIRTY
1686 if (unlikely(is_pmd_migration_entry(pmd)))
1687 pmd = pmd_swp_mksoft_dirty(pmd);
1688 else if (pmd_present(pmd))
1689 pmd = pmd_mksoft_dirty(pmd);
1690#endif
1691 return pmd;
1692}
1693
1694bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
1695 unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd)
1696{
1697 spinlock_t *old_ptl, *new_ptl;
1698 pmd_t pmd;
1699 struct mm_struct *mm = vma->vm_mm;
1700 bool force_flush = false;
1701
1702
1703
1704
1705
1706 if (WARN_ON(!pmd_none(*new_pmd))) {
1707 VM_BUG_ON(pmd_trans_huge(*new_pmd));
1708 return false;
1709 }
1710
1711
1712
1713
1714
1715 old_ptl = __pmd_trans_huge_lock(old_pmd, vma);
1716 if (old_ptl) {
1717 new_ptl = pmd_lockptr(mm, new_pmd);
1718 if (new_ptl != old_ptl)
1719 spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
1720 pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd);
1721 if (pmd_present(pmd))
1722 force_flush = true;
1723 VM_BUG_ON(!pmd_none(*new_pmd));
1724
1725 if (pmd_move_must_withdraw(new_ptl, old_ptl, vma)) {
1726 pgtable_t pgtable;
1727 pgtable = pgtable_trans_huge_withdraw(mm, old_pmd);
1728 pgtable_trans_huge_deposit(mm, new_pmd, pgtable);
1729 }
1730 pmd = move_soft_dirty_pmd(pmd);
1731 set_pmd_at(mm, new_addr, new_pmd, pmd);
1732 if (force_flush)
1733 flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE);
1734 if (new_ptl != old_ptl)
1735 spin_unlock(new_ptl);
1736 spin_unlock(old_ptl);
1737 return true;
1738 }
1739 return false;
1740}
1741
1742
1743
1744
1745
1746
1747
1748
1749int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
1750 unsigned long addr, pgprot_t newprot, unsigned long cp_flags)
1751{
1752 struct mm_struct *mm = vma->vm_mm;
1753 spinlock_t *ptl;
1754 pmd_t entry;
1755 bool preserve_write;
1756 int ret;
1757 bool prot_numa = cp_flags & MM_CP_PROT_NUMA;
1758 bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
1759 bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
1760
1761 if (prot_numa && !thp_migration_supported())
1762 return 1;
1763
1764 ptl = __pmd_trans_huge_lock(pmd, vma);
1765 if (!ptl)
1766 return 0;
1767
1768 preserve_write = prot_numa && pmd_write(*pmd);
1769 ret = 1;
1770
1771#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
1772 if (is_swap_pmd(*pmd)) {
1773 swp_entry_t entry = pmd_to_swp_entry(*pmd);
1774
1775 VM_BUG_ON(!is_pmd_migration_entry(*pmd));
1776 if (is_writable_migration_entry(entry)) {
1777 pmd_t newpmd;
1778
1779
1780
1781
1782 entry = make_readable_migration_entry(
1783 swp_offset(entry));
1784 newpmd = swp_entry_to_pmd(entry);
1785 if (pmd_swp_soft_dirty(*pmd))
1786 newpmd = pmd_swp_mksoft_dirty(newpmd);
1787 if (pmd_swp_uffd_wp(*pmd))
1788 newpmd = pmd_swp_mkuffd_wp(newpmd);
1789 set_pmd_at(mm, addr, pmd, newpmd);
1790 }
1791 goto unlock;
1792 }
1793#endif
1794
1795
1796
1797
1798
1799
1800 if (prot_numa && is_huge_zero_pmd(*pmd))
1801 goto unlock;
1802
1803 if (prot_numa && pmd_protnone(*pmd))
1804 goto unlock;
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827 entry = pmdp_invalidate(vma, addr, pmd);
1828
1829 entry = pmd_modify(entry, newprot);
1830 if (preserve_write)
1831 entry = pmd_mk_savedwrite(entry);
1832 if (uffd_wp) {
1833 entry = pmd_wrprotect(entry);
1834 entry = pmd_mkuffd_wp(entry);
1835 } else if (uffd_wp_resolve) {
1836
1837
1838
1839
1840
1841 entry = pmd_clear_uffd_wp(entry);
1842 }
1843 ret = HPAGE_PMD_NR;
1844 set_pmd_at(mm, addr, pmd, entry);
1845 BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry));
1846unlock:
1847 spin_unlock(ptl);
1848 return ret;
1849}
1850
1851
1852
1853
1854
1855
1856
1857spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma)
1858{
1859 spinlock_t *ptl;
1860 ptl = pmd_lock(vma->vm_mm, pmd);
1861 if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) ||
1862 pmd_devmap(*pmd)))
1863 return ptl;
1864 spin_unlock(ptl);
1865 return NULL;
1866}
1867
1868
1869
1870
1871
1872
1873
1874spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma)
1875{
1876 spinlock_t *ptl;
1877
1878 ptl = pud_lock(vma->vm_mm, pud);
1879 if (likely(pud_trans_huge(*pud) || pud_devmap(*pud)))
1880 return ptl;
1881 spin_unlock(ptl);
1882 return NULL;
1883}
1884
1885#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
1886int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma,
1887 pud_t *pud, unsigned long addr)
1888{
1889 spinlock_t *ptl;
1890
1891 ptl = __pud_trans_huge_lock(pud, vma);
1892 if (!ptl)
1893 return 0;
1894
1895
1896
1897
1898
1899
1900 pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm);
1901 tlb_remove_pud_tlb_entry(tlb, pud, addr);
1902 if (vma_is_special_huge(vma)) {
1903 spin_unlock(ptl);
1904
1905 } else {
1906
1907 BUG();
1908 }
1909 return 1;
1910}
1911
1912static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud,
1913 unsigned long haddr)
1914{
1915 VM_BUG_ON(haddr & ~HPAGE_PUD_MASK);
1916 VM_BUG_ON_VMA(vma->vm_start > haddr, vma);
1917 VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma);
1918 VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud));
1919
1920 count_vm_event(THP_SPLIT_PUD);
1921
1922 pudp_huge_clear_flush_notify(vma, haddr, pud);
1923}
1924
1925void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud,
1926 unsigned long address)
1927{
1928 spinlock_t *ptl;
1929 struct mmu_notifier_range range;
1930
1931 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
1932 address & HPAGE_PUD_MASK,
1933 (address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE);
1934 mmu_notifier_invalidate_range_start(&range);
1935 ptl = pud_lock(vma->vm_mm, pud);
1936 if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud)))
1937 goto out;
1938 __split_huge_pud_locked(vma, pud, range.start);
1939
1940out:
1941 spin_unlock(ptl);
1942
1943
1944
1945
1946 mmu_notifier_invalidate_range_only_end(&range);
1947}
1948#endif
1949
1950static void __split_huge_zero_page_pmd(struct vm_area_struct *vma,
1951 unsigned long haddr, pmd_t *pmd)
1952{
1953 struct mm_struct *mm = vma->vm_mm;
1954 pgtable_t pgtable;
1955 pmd_t _pmd;
1956 int i;
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966 pmdp_huge_clear_flush(vma, haddr, pmd);
1967
1968 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
1969 pmd_populate(mm, &_pmd, pgtable);
1970
1971 for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
1972 pte_t *pte, entry;
1973 entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot);
1974 entry = pte_mkspecial(entry);
1975 pte = pte_offset_map(&_pmd, haddr);
1976 VM_BUG_ON(!pte_none(*pte));
1977 set_pte_at(mm, haddr, pte, entry);
1978 pte_unmap(pte);
1979 }
1980 smp_wmb();
1981 pmd_populate(mm, pmd, pgtable);
1982}
1983
1984static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
1985 unsigned long haddr, bool freeze)
1986{
1987 struct mm_struct *mm = vma->vm_mm;
1988 struct page *page;
1989 pgtable_t pgtable;
1990 pmd_t old_pmd, _pmd;
1991 bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false;
1992 unsigned long addr;
1993 int i;
1994
1995 VM_BUG_ON(haddr & ~HPAGE_PMD_MASK);
1996 VM_BUG_ON_VMA(vma->vm_start > haddr, vma);
1997 VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma);
1998 VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd)
1999 && !pmd_devmap(*pmd));
2000
2001 count_vm_event(THP_SPLIT_PMD);
2002
2003 if (!vma_is_anonymous(vma)) {
2004 old_pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd);
2005
2006
2007
2008
2009 if (arch_needs_pgtable_deposit())
2010 zap_deposited_table(mm, pmd);
2011 if (vma_is_special_huge(vma))
2012 return;
2013 if (unlikely(is_pmd_migration_entry(old_pmd))) {
2014 swp_entry_t entry;
2015
2016 entry = pmd_to_swp_entry(old_pmd);
2017 page = pfn_swap_entry_to_page(entry);
2018 } else {
2019 page = pmd_page(old_pmd);
2020 if (!PageDirty(page) && pmd_dirty(old_pmd))
2021 set_page_dirty(page);
2022 if (!PageReferenced(page) && pmd_young(old_pmd))
2023 SetPageReferenced(page);
2024 page_remove_rmap(page, true);
2025 put_page(page);
2026 }
2027 add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR);
2028 return;
2029 }
2030
2031 if (is_huge_zero_pmd(*pmd)) {
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041 return __split_huge_zero_page_pmd(vma, haddr, pmd);
2042 }
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064 old_pmd = pmdp_invalidate(vma, haddr, pmd);
2065
2066 pmd_migration = is_pmd_migration_entry(old_pmd);
2067 if (unlikely(pmd_migration)) {
2068 swp_entry_t entry;
2069
2070 entry = pmd_to_swp_entry(old_pmd);
2071 page = pfn_swap_entry_to_page(entry);
2072 write = is_writable_migration_entry(entry);
2073 young = false;
2074 soft_dirty = pmd_swp_soft_dirty(old_pmd);
2075 uffd_wp = pmd_swp_uffd_wp(old_pmd);
2076 } else {
2077 page = pmd_page(old_pmd);
2078 if (pmd_dirty(old_pmd))
2079 SetPageDirty(page);
2080 write = pmd_write(old_pmd);
2081 young = pmd_young(old_pmd);
2082 soft_dirty = pmd_soft_dirty(old_pmd);
2083 uffd_wp = pmd_uffd_wp(old_pmd);
2084 }
2085 VM_BUG_ON_PAGE(!page_count(page), page);
2086 page_ref_add(page, HPAGE_PMD_NR - 1);
2087
2088
2089
2090
2091
2092 pgtable = pgtable_trans_huge_withdraw(mm, pmd);
2093 pmd_populate(mm, &_pmd, pgtable);
2094
2095 for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) {
2096 pte_t entry, *pte;
2097
2098
2099
2100
2101
2102 if (freeze || pmd_migration) {
2103 swp_entry_t swp_entry;
2104 if (write)
2105 swp_entry = make_writable_migration_entry(
2106 page_to_pfn(page + i));
2107 else
2108 swp_entry = make_readable_migration_entry(
2109 page_to_pfn(page + i));
2110 entry = swp_entry_to_pte(swp_entry);
2111 if (soft_dirty)
2112 entry = pte_swp_mksoft_dirty(entry);
2113 if (uffd_wp)
2114 entry = pte_swp_mkuffd_wp(entry);
2115 } else {
2116 entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot));
2117 entry = maybe_mkwrite(entry, vma);
2118 if (!write)
2119 entry = pte_wrprotect(entry);
2120 if (!young)
2121 entry = pte_mkold(entry);
2122 if (soft_dirty)
2123 entry = pte_mksoft_dirty(entry);
2124 if (uffd_wp)
2125 entry = pte_mkuffd_wp(entry);
2126 }
2127 pte = pte_offset_map(&_pmd, addr);
2128 BUG_ON(!pte_none(*pte));
2129 set_pte_at(mm, addr, pte, entry);
2130 if (!pmd_migration)
2131 atomic_inc(&page[i]._mapcount);
2132 pte_unmap(pte);
2133 }
2134
2135 if (!pmd_migration) {
2136
2137
2138
2139
2140 if (compound_mapcount(page) > 1 &&
2141 !TestSetPageDoubleMap(page)) {
2142 for (i = 0; i < HPAGE_PMD_NR; i++)
2143 atomic_inc(&page[i]._mapcount);
2144 }
2145
2146 lock_page_memcg(page);
2147 if (atomic_add_negative(-1, compound_mapcount_ptr(page))) {
2148
2149 __mod_lruvec_page_state(page, NR_ANON_THPS,
2150 -HPAGE_PMD_NR);
2151 if (TestClearPageDoubleMap(page)) {
2152
2153 for (i = 0; i < HPAGE_PMD_NR; i++)
2154 atomic_dec(&page[i]._mapcount);
2155 }
2156 }
2157 unlock_page_memcg(page);
2158 }
2159
2160 smp_wmb();
2161 pmd_populate(mm, pmd, pgtable);
2162
2163 if (freeze) {
2164 for (i = 0; i < HPAGE_PMD_NR; i++) {
2165 page_remove_rmap(page + i, false);
2166 put_page(page + i);
2167 }
2168 }
2169}
2170
2171void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
2172 unsigned long address, bool freeze, struct page *page)
2173{
2174 spinlock_t *ptl;
2175 struct mmu_notifier_range range;
2176 bool do_unlock_page = false;
2177 pmd_t _pmd;
2178
2179 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
2180 address & HPAGE_PMD_MASK,
2181 (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE);
2182 mmu_notifier_invalidate_range_start(&range);
2183 ptl = pmd_lock(vma->vm_mm, pmd);
2184
2185
2186
2187
2188
2189 VM_BUG_ON(freeze && !page);
2190 if (page) {
2191 VM_WARN_ON_ONCE(!PageLocked(page));
2192 if (page != pmd_page(*pmd))
2193 goto out;
2194 }
2195
2196repeat:
2197 if (pmd_trans_huge(*pmd)) {
2198 if (!page) {
2199 page = pmd_page(*pmd);
2200
2201
2202
2203
2204
2205
2206
2207 if (PageAnon(page)) {
2208 if (unlikely(!trylock_page(page))) {
2209 get_page(page);
2210 _pmd = *pmd;
2211 spin_unlock(ptl);
2212 lock_page(page);
2213 spin_lock(ptl);
2214 if (unlikely(!pmd_same(*pmd, _pmd))) {
2215 unlock_page(page);
2216 put_page(page);
2217 page = NULL;
2218 goto repeat;
2219 }
2220 put_page(page);
2221 }
2222 do_unlock_page = true;
2223 }
2224 }
2225 if (PageMlocked(page))
2226 clear_page_mlock(page);
2227 } else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd)))
2228 goto out;
2229 __split_huge_pmd_locked(vma, pmd, range.start, freeze);
2230out:
2231 spin_unlock(ptl);
2232 if (do_unlock_page)
2233 unlock_page(page);
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247 mmu_notifier_invalidate_range_only_end(&range);
2248}
2249
2250void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address,
2251 bool freeze, struct page *page)
2252{
2253 pgd_t *pgd;
2254 p4d_t *p4d;
2255 pud_t *pud;
2256 pmd_t *pmd;
2257
2258 pgd = pgd_offset(vma->vm_mm, address);
2259 if (!pgd_present(*pgd))
2260 return;
2261
2262 p4d = p4d_offset(pgd, address);
2263 if (!p4d_present(*p4d))
2264 return;
2265
2266 pud = pud_offset(p4d, address);
2267 if (!pud_present(*pud))
2268 return;
2269
2270 pmd = pmd_offset(pud, address);
2271
2272 __split_huge_pmd(vma, pmd, address, freeze, page);
2273}
2274
2275static inline void split_huge_pmd_if_needed(struct vm_area_struct *vma, unsigned long address)
2276{
2277
2278
2279
2280
2281 if (!IS_ALIGNED(address, HPAGE_PMD_SIZE) &&
2282 range_in_vma(vma, ALIGN_DOWN(address, HPAGE_PMD_SIZE),
2283 ALIGN(address, HPAGE_PMD_SIZE)))
2284 split_huge_pmd_address(vma, address, false, NULL);
2285}
2286
2287void vma_adjust_trans_huge(struct vm_area_struct *vma,
2288 unsigned long start,
2289 unsigned long end,
2290 long adjust_next)
2291{
2292
2293 split_huge_pmd_if_needed(vma, start);
2294
2295
2296 split_huge_pmd_if_needed(vma, end);
2297
2298
2299
2300
2301
2302 if (adjust_next > 0) {
2303 struct vm_area_struct *next = vma->vm_next;
2304 unsigned long nstart = next->vm_start;
2305 nstart += adjust_next;
2306 split_huge_pmd_if_needed(next, nstart);
2307 }
2308}
2309
2310static void unmap_page(struct page *page)
2311{
2312 enum ttu_flags ttu_flags = TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD |
2313 TTU_SYNC;
2314
2315 VM_BUG_ON_PAGE(!PageHead(page), page);
2316
2317
2318
2319
2320
2321
2322 if (PageAnon(page))
2323 try_to_migrate(page, ttu_flags);
2324 else
2325 try_to_unmap(page, ttu_flags | TTU_IGNORE_MLOCK);
2326
2327 VM_WARN_ON_ONCE_PAGE(page_mapped(page), page);
2328}
2329
2330static void remap_page(struct page *page, unsigned int nr)
2331{
2332 int i;
2333
2334
2335 if (!PageAnon(page))
2336 return;
2337 if (PageTransHuge(page)) {
2338 remove_migration_ptes(page, page, true);
2339 } else {
2340 for (i = 0; i < nr; i++)
2341 remove_migration_ptes(page + i, page + i, true);
2342 }
2343}
2344
2345static void lru_add_page_tail(struct page *head, struct page *tail,
2346 struct lruvec *lruvec, struct list_head *list)
2347{
2348 VM_BUG_ON_PAGE(!PageHead(head), head);
2349 VM_BUG_ON_PAGE(PageCompound(tail), head);
2350 VM_BUG_ON_PAGE(PageLRU(tail), head);
2351 lockdep_assert_held(&lruvec->lru_lock);
2352
2353 if (list) {
2354
2355 VM_WARN_ON(PageLRU(head));
2356 get_page(tail);
2357 list_add_tail(&tail->lru, list);
2358 } else {
2359
2360 VM_WARN_ON(!PageLRU(head));
2361 SetPageLRU(tail);
2362 list_add_tail(&tail->lru, &head->lru);
2363 }
2364}
2365
2366static void __split_huge_page_tail(struct page *head, int tail,
2367 struct lruvec *lruvec, struct list_head *list)
2368{
2369 struct page *page_tail = head + tail;
2370
2371 VM_BUG_ON_PAGE(atomic_read(&page_tail->_mapcount) != -1, page_tail);
2372
2373
2374
2375
2376
2377
2378
2379 page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
2380 page_tail->flags |= (head->flags &
2381 ((1L << PG_referenced) |
2382 (1L << PG_swapbacked) |
2383 (1L << PG_swapcache) |
2384 (1L << PG_mlocked) |
2385 (1L << PG_uptodate) |
2386 (1L << PG_active) |
2387 (1L << PG_workingset) |
2388 (1L << PG_locked) |
2389 (1L << PG_unevictable) |
2390#ifdef CONFIG_64BIT
2391 (1L << PG_arch_2) |
2392#endif
2393 (1L << PG_dirty)));
2394
2395
2396 VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING,
2397 page_tail);
2398 page_tail->mapping = head->mapping;
2399 page_tail->index = head->index + tail;
2400
2401
2402 smp_wmb();
2403
2404
2405
2406
2407
2408
2409
2410 clear_compound_head(page_tail);
2411
2412
2413 page_ref_unfreeze(page_tail, 1 + (!PageAnon(head) ||
2414 PageSwapCache(head)));
2415
2416 if (page_is_young(head))
2417 set_page_young(page_tail);
2418 if (page_is_idle(head))
2419 set_page_idle(page_tail);
2420
2421 page_cpupid_xchg_last(page_tail, page_cpupid_last(head));
2422
2423
2424
2425
2426
2427
2428 lru_add_page_tail(head, page_tail, lruvec, list);
2429}
2430
2431static void __split_huge_page(struct page *page, struct list_head *list,
2432 pgoff_t end)
2433{
2434 struct page *head = compound_head(page);
2435 struct lruvec *lruvec;
2436 struct address_space *swap_cache = NULL;
2437 unsigned long offset = 0;
2438 unsigned int nr = thp_nr_pages(head);
2439 int i;
2440
2441
2442 split_page_memcg(head, nr);
2443
2444 if (PageAnon(head) && PageSwapCache(head)) {
2445 swp_entry_t entry = { .val = page_private(head) };
2446
2447 offset = swp_offset(entry);
2448 swap_cache = swap_address_space(entry);
2449 xa_lock(&swap_cache->i_pages);
2450 }
2451
2452
2453 lruvec = lock_page_lruvec(head);
2454
2455 for (i = nr - 1; i >= 1; i--) {
2456 __split_huge_page_tail(head, i, lruvec, list);
2457
2458 if (head[i].index >= end) {
2459 ClearPageDirty(head + i);
2460 __delete_from_page_cache(head + i, NULL);
2461 if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head))
2462 shmem_uncharge(head->mapping->host, 1);
2463 put_page(head + i);
2464 } else if (!PageAnon(page)) {
2465 __xa_store(&head->mapping->i_pages, head[i].index,
2466 head + i, 0);
2467 } else if (swap_cache) {
2468 __xa_store(&swap_cache->i_pages, offset + i,
2469 head + i, 0);
2470 }
2471 }
2472
2473 ClearPageCompound(head);
2474 unlock_page_lruvec(lruvec);
2475
2476
2477 split_page_owner(head, nr);
2478
2479
2480 if (PageAnon(head)) {
2481
2482 if (PageSwapCache(head)) {
2483 page_ref_add(head, 2);
2484 xa_unlock(&swap_cache->i_pages);
2485 } else {
2486 page_ref_inc(head);
2487 }
2488 } else {
2489
2490 page_ref_add(head, 2);
2491 xa_unlock(&head->mapping->i_pages);
2492 }
2493 local_irq_enable();
2494
2495 remap_page(head, nr);
2496
2497 if (PageSwapCache(head)) {
2498 swp_entry_t entry = { .val = page_private(head) };
2499
2500 split_swap_cluster(entry);
2501 }
2502
2503 for (i = 0; i < nr; i++) {
2504 struct page *subpage = head + i;
2505 if (subpage == page)
2506 continue;
2507 unlock_page(subpage);
2508
2509
2510
2511
2512
2513
2514
2515
2516 put_page(subpage);
2517 }
2518}
2519
2520int total_mapcount(struct page *page)
2521{
2522 int i, compound, nr, ret;
2523
2524 VM_BUG_ON_PAGE(PageTail(page), page);
2525
2526 if (likely(!PageCompound(page)))
2527 return atomic_read(&page->_mapcount) + 1;
2528
2529 compound = compound_mapcount(page);
2530 nr = compound_nr(page);
2531 if (PageHuge(page))
2532 return compound;
2533 ret = compound;
2534 for (i = 0; i < nr; i++)
2535 ret += atomic_read(&page[i]._mapcount) + 1;
2536
2537 if (!PageAnon(page))
2538 return ret - compound * nr;
2539 if (PageDoubleMap(page))
2540 ret -= nr;
2541 return ret;
2542}
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568int page_trans_huge_mapcount(struct page *page, int *total_mapcount)
2569{
2570 int i, ret, _total_mapcount, mapcount;
2571
2572
2573 VM_BUG_ON_PAGE(PageHuge(page), page);
2574
2575 if (likely(!PageTransCompound(page))) {
2576 mapcount = atomic_read(&page->_mapcount) + 1;
2577 if (total_mapcount)
2578 *total_mapcount = mapcount;
2579 return mapcount;
2580 }
2581
2582 page = compound_head(page);
2583
2584 _total_mapcount = ret = 0;
2585 for (i = 0; i < thp_nr_pages(page); i++) {
2586 mapcount = atomic_read(&page[i]._mapcount) + 1;
2587 ret = max(ret, mapcount);
2588 _total_mapcount += mapcount;
2589 }
2590 if (PageDoubleMap(page)) {
2591 ret -= 1;
2592 _total_mapcount -= thp_nr_pages(page);
2593 }
2594 mapcount = compound_mapcount(page);
2595 ret += mapcount;
2596 _total_mapcount += mapcount;
2597 if (total_mapcount)
2598 *total_mapcount = _total_mapcount;
2599 return ret;
2600}
2601
2602
2603bool can_split_huge_page(struct page *page, int *pextra_pins)
2604{
2605 int extra_pins;
2606
2607
2608 if (PageAnon(page))
2609 extra_pins = PageSwapCache(page) ? thp_nr_pages(page) : 0;
2610 else
2611 extra_pins = thp_nr_pages(page);
2612 if (pextra_pins)
2613 *pextra_pins = extra_pins;
2614 return total_mapcount(page) == page_count(page) - extra_pins - 1;
2615}
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636int split_huge_page_to_list(struct page *page, struct list_head *list)
2637{
2638 struct page *head = compound_head(page);
2639 struct deferred_split *ds_queue = get_deferred_split_queue(head);
2640 struct anon_vma *anon_vma = NULL;
2641 struct address_space *mapping = NULL;
2642 int extra_pins, ret;
2643 pgoff_t end;
2644
2645 VM_BUG_ON_PAGE(is_huge_zero_page(head), head);
2646 VM_BUG_ON_PAGE(!PageLocked(head), head);
2647 VM_BUG_ON_PAGE(!PageCompound(head), head);
2648
2649 if (PageWriteback(head))
2650 return -EBUSY;
2651
2652 if (PageAnon(head)) {
2653
2654
2655
2656
2657
2658
2659
2660
2661 anon_vma = page_get_anon_vma(head);
2662 if (!anon_vma) {
2663 ret = -EBUSY;
2664 goto out;
2665 }
2666 end = -1;
2667 mapping = NULL;
2668 anon_vma_lock_write(anon_vma);
2669 } else {
2670 mapping = head->mapping;
2671
2672
2673 if (!mapping) {
2674 ret = -EBUSY;
2675 goto out;
2676 }
2677
2678 anon_vma = NULL;
2679 i_mmap_lock_read(mapping);
2680
2681
2682
2683
2684
2685
2686
2687
2688 end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE);
2689 }
2690
2691
2692
2693
2694
2695 if (!can_split_huge_page(head, &extra_pins)) {
2696 ret = -EBUSY;
2697 goto out_unlock;
2698 }
2699
2700 unmap_page(head);
2701
2702
2703 local_irq_disable();
2704 if (mapping) {
2705 XA_STATE(xas, &mapping->i_pages, page_index(head));
2706
2707
2708
2709
2710
2711 xa_lock(&mapping->i_pages);
2712 if (xas_load(&xas) != head)
2713 goto fail;
2714 }
2715
2716
2717 spin_lock(&ds_queue->split_queue_lock);
2718 if (page_ref_freeze(head, 1 + extra_pins)) {
2719 if (!list_empty(page_deferred_list(head))) {
2720 ds_queue->split_queue_len--;
2721 list_del(page_deferred_list(head));
2722 }
2723 spin_unlock(&ds_queue->split_queue_lock);
2724 if (mapping) {
2725 int nr = thp_nr_pages(head);
2726
2727 if (PageSwapBacked(head))
2728 __mod_lruvec_page_state(head, NR_SHMEM_THPS,
2729 -nr);
2730 else
2731 __mod_lruvec_page_state(head, NR_FILE_THPS,
2732 -nr);
2733 }
2734
2735 __split_huge_page(page, list, end);
2736 ret = 0;
2737 } else {
2738 spin_unlock(&ds_queue->split_queue_lock);
2739fail:
2740 if (mapping)
2741 xa_unlock(&mapping->i_pages);
2742 local_irq_enable();
2743 remap_page(head, thp_nr_pages(head));
2744 ret = -EBUSY;
2745 }
2746
2747out_unlock:
2748 if (anon_vma) {
2749 anon_vma_unlock_write(anon_vma);
2750 put_anon_vma(anon_vma);
2751 }
2752 if (mapping)
2753 i_mmap_unlock_read(mapping);
2754out:
2755 count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED);
2756 return ret;
2757}
2758
2759void free_transhuge_page(struct page *page)
2760{
2761 struct deferred_split *ds_queue = get_deferred_split_queue(page);
2762 unsigned long flags;
2763
2764 spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
2765 if (!list_empty(page_deferred_list(page))) {
2766 ds_queue->split_queue_len--;
2767 list_del(page_deferred_list(page));
2768 }
2769 spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
2770 free_compound_page(page);
2771}
2772
2773void deferred_split_huge_page(struct page *page)
2774{
2775 struct deferred_split *ds_queue = get_deferred_split_queue(page);
2776#ifdef CONFIG_MEMCG
2777 struct mem_cgroup *memcg = page_memcg(compound_head(page));
2778#endif
2779 unsigned long flags;
2780
2781 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793 if (PageSwapCache(page))
2794 return;
2795
2796 spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
2797 if (list_empty(page_deferred_list(page))) {
2798 count_vm_event(THP_DEFERRED_SPLIT_PAGE);
2799 list_add_tail(page_deferred_list(page), &ds_queue->split_queue);
2800 ds_queue->split_queue_len++;
2801#ifdef CONFIG_MEMCG
2802 if (memcg)
2803 set_shrinker_bit(memcg, page_to_nid(page),
2804 deferred_split_shrinker.id);
2805#endif
2806 }
2807 spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
2808}
2809
2810static unsigned long deferred_split_count(struct shrinker *shrink,
2811 struct shrink_control *sc)
2812{
2813 struct pglist_data *pgdata = NODE_DATA(sc->nid);
2814 struct deferred_split *ds_queue = &pgdata->deferred_split_queue;
2815
2816#ifdef CONFIG_MEMCG
2817 if (sc->memcg)
2818 ds_queue = &sc->memcg->deferred_split_queue;
2819#endif
2820 return READ_ONCE(ds_queue->split_queue_len);
2821}
2822
2823static unsigned long deferred_split_scan(struct shrinker *shrink,
2824 struct shrink_control *sc)
2825{
2826 struct pglist_data *pgdata = NODE_DATA(sc->nid);
2827 struct deferred_split *ds_queue = &pgdata->deferred_split_queue;
2828 unsigned long flags;
2829 LIST_HEAD(list), *pos, *next;
2830 struct page *page;
2831 int split = 0;
2832
2833#ifdef CONFIG_MEMCG
2834 if (sc->memcg)
2835 ds_queue = &sc->memcg->deferred_split_queue;
2836#endif
2837
2838 spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
2839
2840 list_for_each_safe(pos, next, &ds_queue->split_queue) {
2841 page = list_entry((void *)pos, struct page, deferred_list);
2842 page = compound_head(page);
2843 if (get_page_unless_zero(page)) {
2844 list_move(page_deferred_list(page), &list);
2845 } else {
2846
2847 list_del_init(page_deferred_list(page));
2848 ds_queue->split_queue_len--;
2849 }
2850 if (!--sc->nr_to_scan)
2851 break;
2852 }
2853 spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
2854
2855 list_for_each_safe(pos, next, &list) {
2856 page = list_entry((void *)pos, struct page, deferred_list);
2857 if (!trylock_page(page))
2858 goto next;
2859
2860 if (!split_huge_page(page))
2861 split++;
2862 unlock_page(page);
2863next:
2864 put_page(page);
2865 }
2866
2867 spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
2868 list_splice_tail(&list, &ds_queue->split_queue);
2869 spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
2870
2871
2872
2873
2874
2875 if (!split && list_empty(&ds_queue->split_queue))
2876 return SHRINK_STOP;
2877 return split;
2878}
2879
2880static struct shrinker deferred_split_shrinker = {
2881 .count_objects = deferred_split_count,
2882 .scan_objects = deferred_split_scan,
2883 .seeks = DEFAULT_SEEKS,
2884 .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE |
2885 SHRINKER_NONSLAB,
2886};
2887
2888#ifdef CONFIG_DEBUG_FS
2889static void split_huge_pages_all(void)
2890{
2891 struct zone *zone;
2892 struct page *page;
2893 unsigned long pfn, max_zone_pfn;
2894 unsigned long total = 0, split = 0;
2895
2896 pr_debug("Split all THPs\n");
2897 for_each_populated_zone(zone) {
2898 max_zone_pfn = zone_end_pfn(zone);
2899 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) {
2900 if (!pfn_valid(pfn))
2901 continue;
2902
2903 page = pfn_to_page(pfn);
2904 if (!get_page_unless_zero(page))
2905 continue;
2906
2907 if (zone != page_zone(page))
2908 goto next;
2909
2910 if (!PageHead(page) || PageHuge(page) || !PageLRU(page))
2911 goto next;
2912
2913 total++;
2914 lock_page(page);
2915 if (!split_huge_page(page))
2916 split++;
2917 unlock_page(page);
2918next:
2919 put_page(page);
2920 cond_resched();
2921 }
2922 }
2923
2924 pr_debug("%lu of %lu THP split\n", split, total);
2925}
2926
2927static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma)
2928{
2929 return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) ||
2930 is_vm_hugetlb_page(vma);
2931}
2932
2933static int split_huge_pages_pid(int pid, unsigned long vaddr_start,
2934 unsigned long vaddr_end)
2935{
2936 int ret = 0;
2937 struct task_struct *task;
2938 struct mm_struct *mm;
2939 unsigned long total = 0, split = 0;
2940 unsigned long addr;
2941
2942 vaddr_start &= PAGE_MASK;
2943 vaddr_end &= PAGE_MASK;
2944
2945
2946 rcu_read_lock();
2947 task = find_task_by_vpid(pid);
2948 if (!task) {
2949 rcu_read_unlock();
2950 ret = -ESRCH;
2951 goto out;
2952 }
2953 get_task_struct(task);
2954 rcu_read_unlock();
2955
2956
2957 mm = get_task_mm(task);
2958 put_task_struct(task);
2959
2960 if (!mm) {
2961 ret = -EINVAL;
2962 goto out;
2963 }
2964
2965 pr_debug("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n",
2966 pid, vaddr_start, vaddr_end);
2967
2968 mmap_read_lock(mm);
2969
2970
2971
2972
2973 for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) {
2974 struct vm_area_struct *vma = find_vma(mm, addr);
2975 unsigned int follflags;
2976 struct page *page;
2977
2978 if (!vma || addr < vma->vm_start)
2979 break;
2980
2981
2982 if (vma_not_suitable_for_thp_split(vma)) {
2983 addr = vma->vm_end;
2984 continue;
2985 }
2986
2987
2988 follflags = FOLL_GET | FOLL_DUMP;
2989 page = follow_page(vma, addr, follflags);
2990
2991 if (IS_ERR(page))
2992 continue;
2993 if (!page)
2994 continue;
2995
2996 if (!is_transparent_hugepage(page))
2997 goto next;
2998
2999 total++;
3000 if (!can_split_huge_page(compound_head(page), NULL))
3001 goto next;
3002
3003 if (!trylock_page(page))
3004 goto next;
3005
3006 if (!split_huge_page(page))
3007 split++;
3008
3009 unlock_page(page);
3010next:
3011 put_page(page);
3012 cond_resched();
3013 }
3014 mmap_read_unlock(mm);
3015 mmput(mm);
3016
3017 pr_debug("%lu of %lu THP split\n", split, total);
3018
3019out:
3020 return ret;
3021}
3022
3023static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start,
3024 pgoff_t off_end)
3025{
3026 struct filename *file;
3027 struct file *candidate;
3028 struct address_space *mapping;
3029 int ret = -EINVAL;
3030 pgoff_t index;
3031 int nr_pages = 1;
3032 unsigned long total = 0, split = 0;
3033
3034 file = getname_kernel(file_path);
3035 if (IS_ERR(file))
3036 return ret;
3037
3038 candidate = file_open_name(file, O_RDONLY, 0);
3039 if (IS_ERR(candidate))
3040 goto out;
3041
3042 pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n",
3043 file_path, off_start, off_end);
3044
3045 mapping = candidate->f_mapping;
3046
3047 for (index = off_start; index < off_end; index += nr_pages) {
3048 struct page *fpage = pagecache_get_page(mapping, index,
3049 FGP_ENTRY | FGP_HEAD, 0);
3050
3051 nr_pages = 1;
3052 if (xa_is_value(fpage) || !fpage)
3053 continue;
3054
3055 if (!is_transparent_hugepage(fpage))
3056 goto next;
3057
3058 total++;
3059 nr_pages = thp_nr_pages(fpage);
3060
3061 if (!trylock_page(fpage))
3062 goto next;
3063
3064 if (!split_huge_page(fpage))
3065 split++;
3066
3067 unlock_page(fpage);
3068next:
3069 put_page(fpage);
3070 cond_resched();
3071 }
3072
3073 filp_close(candidate, NULL);
3074 ret = 0;
3075
3076 pr_debug("%lu of %lu file-backed THP split\n", split, total);
3077out:
3078 putname(file);
3079 return ret;
3080}
3081
3082#define MAX_INPUT_BUF_SZ 255
3083
3084static ssize_t split_huge_pages_write(struct file *file, const char __user *buf,
3085 size_t count, loff_t *ppops)
3086{
3087 static DEFINE_MUTEX(split_debug_mutex);
3088 ssize_t ret;
3089
3090 char input_buf[MAX_INPUT_BUF_SZ];
3091 int pid;
3092 unsigned long vaddr_start, vaddr_end;
3093
3094 ret = mutex_lock_interruptible(&split_debug_mutex);
3095 if (ret)
3096 return ret;
3097
3098 ret = -EFAULT;
3099
3100 memset(input_buf, 0, MAX_INPUT_BUF_SZ);
3101 if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ)))
3102 goto out;
3103
3104 input_buf[MAX_INPUT_BUF_SZ - 1] = '\0';
3105
3106 if (input_buf[0] == '/') {
3107 char *tok;
3108 char *buf = input_buf;
3109 char file_path[MAX_INPUT_BUF_SZ];
3110 pgoff_t off_start = 0, off_end = 0;
3111 size_t input_len = strlen(input_buf);
3112
3113 tok = strsep(&buf, ",");
3114 if (tok) {
3115 strcpy(file_path, tok);
3116 } else {
3117 ret = -EINVAL;
3118 goto out;
3119 }
3120
3121 ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end);
3122 if (ret != 2) {
3123 ret = -EINVAL;
3124 goto out;
3125 }
3126 ret = split_huge_pages_in_file(file_path, off_start, off_end);
3127 if (!ret)
3128 ret = input_len;
3129
3130 goto out;
3131 }
3132
3133 ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end);
3134 if (ret == 1 && pid == 1) {
3135 split_huge_pages_all();
3136 ret = strlen(input_buf);
3137 goto out;
3138 } else if (ret != 3) {
3139 ret = -EINVAL;
3140 goto out;
3141 }
3142
3143 ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end);
3144 if (!ret)
3145 ret = strlen(input_buf);
3146out:
3147 mutex_unlock(&split_debug_mutex);
3148 return ret;
3149
3150}
3151
3152static const struct file_operations split_huge_pages_fops = {
3153 .owner = THIS_MODULE,
3154 .write = split_huge_pages_write,
3155 .llseek = no_llseek,
3156};
3157
3158static int __init split_huge_pages_debugfs(void)
3159{
3160 debugfs_create_file("split_huge_pages", 0200, NULL, NULL,
3161 &split_huge_pages_fops);
3162 return 0;
3163}
3164late_initcall(split_huge_pages_debugfs);
3165#endif
3166
3167#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
3168void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
3169 struct page *page)
3170{
3171 struct vm_area_struct *vma = pvmw->vma;
3172 struct mm_struct *mm = vma->vm_mm;
3173 unsigned long address = pvmw->address;
3174 pmd_t pmdval;
3175 swp_entry_t entry;
3176 pmd_t pmdswp;
3177
3178 if (!(pvmw->pmd && !pvmw->pte))
3179 return;
3180
3181 flush_cache_range(vma, address, address + HPAGE_PMD_SIZE);
3182 pmdval = pmdp_invalidate(vma, address, pvmw->pmd);
3183 if (pmd_dirty(pmdval))
3184 set_page_dirty(page);
3185 if (pmd_write(pmdval))
3186 entry = make_writable_migration_entry(page_to_pfn(page));
3187 else
3188 entry = make_readable_migration_entry(page_to_pfn(page));
3189 pmdswp = swp_entry_to_pmd(entry);
3190 if (pmd_soft_dirty(pmdval))
3191 pmdswp = pmd_swp_mksoft_dirty(pmdswp);
3192 set_pmd_at(mm, address, pvmw->pmd, pmdswp);
3193 page_remove_rmap(page, true);
3194 put_page(page);
3195}
3196
3197void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new)
3198{
3199 struct vm_area_struct *vma = pvmw->vma;
3200 struct mm_struct *mm = vma->vm_mm;
3201 unsigned long address = pvmw->address;
3202 unsigned long mmun_start = address & HPAGE_PMD_MASK;
3203 pmd_t pmde;
3204 swp_entry_t entry;
3205
3206 if (!(pvmw->pmd && !pvmw->pte))
3207 return;
3208
3209 entry = pmd_to_swp_entry(*pvmw->pmd);
3210 get_page(new);
3211 pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot));
3212 if (pmd_swp_soft_dirty(*pvmw->pmd))
3213 pmde = pmd_mksoft_dirty(pmde);
3214 if (is_writable_migration_entry(entry))
3215 pmde = maybe_pmd_mkwrite(pmde, vma);
3216 if (pmd_swp_uffd_wp(*pvmw->pmd))
3217 pmde = pmd_wrprotect(pmd_mkuffd_wp(pmde));
3218
3219 flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE);
3220 if (PageAnon(new))
3221 page_add_anon_rmap(new, vma, mmun_start, true);
3222 else
3223 page_add_file_rmap(new, true);
3224 set_pmd_at(mm, mmun_start, pvmw->pmd, pmde);
3225 if ((vma->vm_flags & VM_LOCKED) && !PageDoubleMap(new))
3226 mlock_vma_page(new);
3227 update_mmu_cache_pmd(vma, address, pvmw->pmd);
3228}
3229#endif
3230