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8#include <linux/mm.h>
9#include <linux/slab.h>
10#include <linux/export.h>
11#include <linux/balloon_compaction.h>
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23struct page *balloon_page_enqueue(struct balloon_dev_info *b_dev_info)
24{
25 unsigned long flags;
26 struct page *page = alloc_page(balloon_mapping_gfp_mask() |
27 __GFP_NOMEMALLOC | __GFP_NORETRY);
28 if (!page)
29 return NULL;
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35
36 BUG_ON(!trylock_page(page));
37 spin_lock_irqsave(&b_dev_info->pages_lock, flags);
38 balloon_page_insert(b_dev_info, page);
39 __count_vm_event(BALLOON_INFLATE);
40 spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
41 unlock_page(page);
42 return page;
43}
44EXPORT_SYMBOL_GPL(balloon_page_enqueue);
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56
57struct page *balloon_page_dequeue(struct balloon_dev_info *b_dev_info)
58{
59 struct page *page, *tmp;
60 unsigned long flags;
61 bool dequeued_page;
62
63 dequeued_page = false;
64 spin_lock_irqsave(&b_dev_info->pages_lock, flags);
65 list_for_each_entry_safe(page, tmp, &b_dev_info->pages, lru) {
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71 if (trylock_page(page)) {
72#ifdef CONFIG_BALLOON_COMPACTION
73 if (!PagePrivate(page)) {
74
75 unlock_page(page);
76 continue;
77 }
78#endif
79 balloon_page_delete(page);
80 __count_vm_event(BALLOON_DEFLATE);
81 unlock_page(page);
82 dequeued_page = true;
83 break;
84 }
85 }
86 spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
87
88 if (!dequeued_page) {
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96 spin_lock_irqsave(&b_dev_info->pages_lock, flags);
97 if (unlikely(list_empty(&b_dev_info->pages) &&
98 !b_dev_info->isolated_pages))
99 BUG();
100 spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
101 page = NULL;
102 }
103 return page;
104}
105EXPORT_SYMBOL_GPL(balloon_page_dequeue);
106
107#ifdef CONFIG_BALLOON_COMPACTION
108
109static inline void __isolate_balloon_page(struct page *page)
110{
111 struct balloon_dev_info *b_dev_info = balloon_page_device(page);
112 unsigned long flags;
113
114 spin_lock_irqsave(&b_dev_info->pages_lock, flags);
115 ClearPagePrivate(page);
116 list_del(&page->lru);
117 b_dev_info->isolated_pages++;
118 spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
119}
120
121static inline void __putback_balloon_page(struct page *page)
122{
123 struct balloon_dev_info *b_dev_info = balloon_page_device(page);
124 unsigned long flags;
125
126 spin_lock_irqsave(&b_dev_info->pages_lock, flags);
127 SetPagePrivate(page);
128 list_add(&page->lru, &b_dev_info->pages);
129 b_dev_info->isolated_pages--;
130 spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
131}
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133
134bool balloon_page_isolate(struct page *page)
135{
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145 if (likely(get_page_unless_zero(page))) {
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157 if (likely(trylock_page(page))) {
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163 if (balloon_page_movable(page)) {
164 __isolate_balloon_page(page);
165 unlock_page(page);
166 return true;
167 }
168 unlock_page(page);
169 }
170 put_page(page);
171 }
172 return false;
173}
174
175
176void balloon_page_putback(struct page *page)
177{
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182 lock_page(page);
183
184 if (__is_movable_balloon_page(page)) {
185 __putback_balloon_page(page);
186
187 put_page(page);
188 } else {
189 WARN_ON(1);
190 dump_page(page, "not movable balloon page");
191 }
192 unlock_page(page);
193}
194
195
196int balloon_page_migrate(struct page *newpage,
197 struct page *page, enum migrate_mode mode)
198{
199 struct balloon_dev_info *balloon = balloon_page_device(page);
200 int rc = -EAGAIN;
201
202 VM_BUG_ON_PAGE(!PageLocked(page), page);
203 VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
204
205 if (WARN_ON(!__is_movable_balloon_page(page))) {
206 dump_page(page, "not movable balloon page");
207 return rc;
208 }
209
210 if (balloon && balloon->migratepage)
211 rc = balloon->migratepage(balloon, newpage, page, mode);
212
213 return rc;
214}
215#endif
216