[PATCH] Kprobes: Track kprobe on a per_cpu basis - i386 changes
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / mm / truncate.c
blob29c18f68dc35cd9b1cc17ee6e5f21bf05d3658e7
1 /*
2 * mm/truncate.c - code for taking down pages from address_spaces
4 * Copyright (C) 2002, Linus Torvalds
6 * 10Sep2002 akpm@zip.com.au
7 * Initial version.
8 */
10 #include <linux/kernel.h>
11 #include <linux/mm.h>
12 #include <linux/module.h>
13 #include <linux/pagemap.h>
14 #include <linux/pagevec.h>
15 #include <linux/buffer_head.h> /* grr. try_to_release_page,
16 do_invalidatepage */
19 static inline void truncate_partial_page(struct page *page, unsigned partial)
21 memclear_highpage_flush(page, partial, PAGE_CACHE_SIZE-partial);
22 if (PagePrivate(page))
23 do_invalidatepage(page, partial);
27 * If truncate cannot remove the fs-private metadata from the page, the page
28 * becomes anonymous. It will be left on the LRU and may even be mapped into
29 * user pagetables if we're racing with filemap_nopage().
31 * We need to bale out if page->mapping is no longer equal to the original
32 * mapping. This happens a) when the VM reclaimed the page while we waited on
33 * its lock, b) when a concurrent invalidate_inode_pages got there first and
34 * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space.
36 static void
37 truncate_complete_page(struct address_space *mapping, struct page *page)
39 if (page->mapping != mapping)
40 return;
42 if (PagePrivate(page))
43 do_invalidatepage(page, 0);
45 clear_page_dirty(page);
46 ClearPageUptodate(page);
47 ClearPageMappedToDisk(page);
48 remove_from_page_cache(page);
49 page_cache_release(page); /* pagecache ref */
53 * This is for invalidate_inode_pages(). That function can be called at
54 * any time, and is not supposed to throw away dirty pages. But pages can
55 * be marked dirty at any time too. So we re-check the dirtiness inside
56 * ->tree_lock. That provides exclusion against the __set_page_dirty
57 * functions.
59 * Returns non-zero if the page was successfully invalidated.
61 static int
62 invalidate_complete_page(struct address_space *mapping, struct page *page)
64 if (page->mapping != mapping)
65 return 0;
67 if (PagePrivate(page) && !try_to_release_page(page, 0))
68 return 0;
70 write_lock_irq(&mapping->tree_lock);
71 if (PageDirty(page)) {
72 write_unlock_irq(&mapping->tree_lock);
73 return 0;
76 BUG_ON(PagePrivate(page));
77 __remove_from_page_cache(page);
78 write_unlock_irq(&mapping->tree_lock);
79 ClearPageUptodate(page);
80 page_cache_release(page); /* pagecache ref */
81 return 1;
84 /**
85 * truncate_inode_pages - truncate *all* the pages from an offset
86 * @mapping: mapping to truncate
87 * @lstart: offset from which to truncate
89 * Truncate the page cache at a set offset, removing the pages that are beyond
90 * that offset (and zeroing out partial pages).
92 * Truncate takes two passes - the first pass is nonblocking. It will not
93 * block on page locks and it will not block on writeback. The second pass
94 * will wait. This is to prevent as much IO as possible in the affected region.
95 * The first pass will remove most pages, so the search cost of the second pass
96 * is low.
98 * When looking at page->index outside the page lock we need to be careful to
99 * copy it into a local to avoid races (it could change at any time).
101 * We pass down the cache-hot hint to the page freeing code. Even if the
102 * mapping is large, it is probably the case that the final pages are the most
103 * recently touched, and freeing happens in ascending file offset order.
105 * Called under (and serialised by) inode->i_sem.
107 void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
109 const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
110 const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1);
111 struct pagevec pvec;
112 pgoff_t next;
113 int i;
115 if (mapping->nrpages == 0)
116 return;
118 pagevec_init(&pvec, 0);
119 next = start;
120 while (pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
121 for (i = 0; i < pagevec_count(&pvec); i++) {
122 struct page *page = pvec.pages[i];
123 pgoff_t page_index = page->index;
125 if (page_index > next)
126 next = page_index;
127 next++;
128 if (TestSetPageLocked(page))
129 continue;
130 if (PageWriteback(page)) {
131 unlock_page(page);
132 continue;
134 truncate_complete_page(mapping, page);
135 unlock_page(page);
137 pagevec_release(&pvec);
138 cond_resched();
141 if (partial) {
142 struct page *page = find_lock_page(mapping, start - 1);
143 if (page) {
144 wait_on_page_writeback(page);
145 truncate_partial_page(page, partial);
146 unlock_page(page);
147 page_cache_release(page);
151 next = start;
152 for ( ; ; ) {
153 cond_resched();
154 if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
155 if (next == start)
156 break;
157 next = start;
158 continue;
160 for (i = 0; i < pagevec_count(&pvec); i++) {
161 struct page *page = pvec.pages[i];
163 lock_page(page);
164 wait_on_page_writeback(page);
165 if (page->index > next)
166 next = page->index;
167 next++;
168 truncate_complete_page(mapping, page);
169 unlock_page(page);
171 pagevec_release(&pvec);
175 EXPORT_SYMBOL(truncate_inode_pages);
178 * invalidate_mapping_pages - Invalidate all the unlocked pages of one inode
179 * @mapping: the address_space which holds the pages to invalidate
180 * @start: the offset 'from' which to invalidate
181 * @end: the offset 'to' which to invalidate (inclusive)
183 * This function only removes the unlocked pages, if you want to
184 * remove all the pages of one inode, you must call truncate_inode_pages.
186 * invalidate_mapping_pages() will not block on IO activity. It will not
187 * invalidate pages which are dirty, locked, under writeback or mapped into
188 * pagetables.
190 unsigned long invalidate_mapping_pages(struct address_space *mapping,
191 pgoff_t start, pgoff_t end)
193 struct pagevec pvec;
194 pgoff_t next = start;
195 unsigned long ret = 0;
196 int i;
198 pagevec_init(&pvec, 0);
199 while (next <= end &&
200 pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
201 for (i = 0; i < pagevec_count(&pvec); i++) {
202 struct page *page = pvec.pages[i];
204 if (TestSetPageLocked(page)) {
205 next++;
206 continue;
208 if (page->index > next)
209 next = page->index;
210 next++;
211 if (PageDirty(page) || PageWriteback(page))
212 goto unlock;
213 if (page_mapped(page))
214 goto unlock;
215 ret += invalidate_complete_page(mapping, page);
216 unlock:
217 unlock_page(page);
218 if (next > end)
219 break;
221 pagevec_release(&pvec);
222 cond_resched();
224 return ret;
227 unsigned long invalidate_inode_pages(struct address_space *mapping)
229 return invalidate_mapping_pages(mapping, 0, ~0UL);
232 EXPORT_SYMBOL(invalidate_inode_pages);
235 * invalidate_inode_pages2_range - remove range of pages from an address_space
236 * @mapping: the address_space
237 * @start: the page offset 'from' which to invalidate
238 * @end: the page offset 'to' which to invalidate (inclusive)
240 * Any pages which are found to be mapped into pagetables are unmapped prior to
241 * invalidation.
243 * Returns -EIO if any pages could not be invalidated.
245 int invalidate_inode_pages2_range(struct address_space *mapping,
246 pgoff_t start, pgoff_t end)
248 struct pagevec pvec;
249 pgoff_t next;
250 int i;
251 int ret = 0;
252 int did_range_unmap = 0;
253 int wrapped = 0;
255 pagevec_init(&pvec, 0);
256 next = start;
257 while (next <= end && !ret && !wrapped &&
258 pagevec_lookup(&pvec, mapping, next,
259 min(end - next, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) {
260 for (i = 0; !ret && i < pagevec_count(&pvec); i++) {
261 struct page *page = pvec.pages[i];
262 pgoff_t page_index;
263 int was_dirty;
265 lock_page(page);
266 if (page->mapping != mapping) {
267 unlock_page(page);
268 continue;
270 page_index = page->index;
271 next = page_index + 1;
272 if (next == 0)
273 wrapped = 1;
274 if (page_index > end) {
275 unlock_page(page);
276 break;
278 wait_on_page_writeback(page);
279 while (page_mapped(page)) {
280 if (!did_range_unmap) {
282 * Zap the rest of the file in one hit.
284 unmap_mapping_range(mapping,
285 page_index << PAGE_CACHE_SHIFT,
286 (end - page_index + 1)
287 << PAGE_CACHE_SHIFT,
289 did_range_unmap = 1;
290 } else {
292 * Just zap this page
294 unmap_mapping_range(mapping,
295 page_index << PAGE_CACHE_SHIFT,
296 PAGE_CACHE_SIZE, 0);
299 was_dirty = test_clear_page_dirty(page);
300 if (!invalidate_complete_page(mapping, page)) {
301 if (was_dirty)
302 set_page_dirty(page);
303 ret = -EIO;
305 unlock_page(page);
307 pagevec_release(&pvec);
308 cond_resched();
310 return ret;
312 EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);
315 * invalidate_inode_pages2 - remove all pages from an address_space
316 * @mapping: the address_space
318 * Any pages which are found to be mapped into pagetables are unmapped prior to
319 * invalidation.
321 * Returns -EIO if any pages could not be invalidated.
323 int invalidate_inode_pages2(struct address_space *mapping)
325 return invalidate_inode_pages2_range(mapping, 0, -1);
327 EXPORT_SYMBOL_GPL(invalidate_inode_pages2);