migrate.c (c3cc99ff5d24e2eeaf7ec2032e720681916990e3) migrate.c (e286781d5f2e9c846e012a39653a166e9d31777d)
1/*
2 * Memory Migration functionality - linux/mm/migration.c
3 *
4 * Copyright (C) 2006 Silicon Graphics, Inc., Christoph Lameter
5 *
6 * Page migration was first developed in the context of the memory hotplug
7 * project. The main authors of the migration code are:
8 *

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280 goto out;
281
282 entry = pte_to_swp_entry(pte);
283 if (!is_migration_entry(entry))
284 goto out;
285
286 page = migration_entry_to_page(entry);
287
1/*
2 * Memory Migration functionality - linux/mm/migration.c
3 *
4 * Copyright (C) 2006 Silicon Graphics, Inc., Christoph Lameter
5 *
6 * Page migration was first developed in the context of the memory hotplug
7 * project. The main authors of the migration code are:
8 *

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280 goto out;
281
282 entry = pte_to_swp_entry(pte);
283 if (!is_migration_entry(entry))
284 goto out;
285
286 page = migration_entry_to_page(entry);
287
288 get_page(page);
288 /*
289 * Once radix-tree replacement of page migration started, page_count
290 * *must* be zero. And, we don't want to call wait_on_page_locked()
291 * against a page without get_page().
292 * So, we use get_page_unless_zero(), here. Even failed, page fault
293 * will occur again.
294 */
295 if (!get_page_unless_zero(page))
296 goto out;
289 pte_unmap_unlock(ptep, ptl);
290 wait_on_page_locked(page);
291 put_page(page);
292 return;
293out:
294 pte_unmap_unlock(ptep, ptl);
295}
296
297/*
298 * Replace the page in the mapping.
299 *
300 * The number of remaining references must be:
301 * 1 for anonymous pages without a mapping
302 * 2 for pages with a mapping
303 * 3 for pages with a mapping and PagePrivate set.
304 */
305static int migrate_page_move_mapping(struct address_space *mapping,
306 struct page *newpage, struct page *page)
307{
297 pte_unmap_unlock(ptep, ptl);
298 wait_on_page_locked(page);
299 put_page(page);
300 return;
301out:
302 pte_unmap_unlock(ptep, ptl);
303}
304
305/*
306 * Replace the page in the mapping.
307 *
308 * The number of remaining references must be:
309 * 1 for anonymous pages without a mapping
310 * 2 for pages with a mapping
311 * 3 for pages with a mapping and PagePrivate set.
312 */
313static int migrate_page_move_mapping(struct address_space *mapping,
314 struct page *newpage, struct page *page)
315{
316 int expected_count;
308 void **pslot;
309
310 if (!mapping) {
311 /* Anonymous page without mapping */
312 if (page_count(page) != 1)
313 return -EAGAIN;
314 return 0;
315 }
316
317 write_lock_irq(&mapping->tree_lock);
318
319 pslot = radix_tree_lookup_slot(&mapping->page_tree,
320 page_index(page));
321
317 void **pslot;
318
319 if (!mapping) {
320 /* Anonymous page without mapping */
321 if (page_count(page) != 1)
322 return -EAGAIN;
323 return 0;
324 }
325
326 write_lock_irq(&mapping->tree_lock);
327
328 pslot = radix_tree_lookup_slot(&mapping->page_tree,
329 page_index(page));
330
322 if (page_count(page) != 2 + !!PagePrivate(page) ||
331 expected_count = 2 + !!PagePrivate(page);
332 if (page_count(page) != expected_count ||
323 (struct page *)radix_tree_deref_slot(pslot) != page) {
324 write_unlock_irq(&mapping->tree_lock);
325 return -EAGAIN;
326 }
327
333 (struct page *)radix_tree_deref_slot(pslot) != page) {
334 write_unlock_irq(&mapping->tree_lock);
335 return -EAGAIN;
336 }
337
338 if (!page_freeze_refs(page, expected_count)) {
339 write_unlock_irq(&mapping->tree_lock);
340 return -EAGAIN;
341 }
342
328 /*
329 * Now we know that no one else is looking at the page.
330 */
331 get_page(newpage); /* add cache reference */
332#ifdef CONFIG_SWAP
333 if (PageSwapCache(page)) {
334 SetPageSwapCache(newpage);
335 set_page_private(newpage, page_private(page));
336 }
337#endif
338
339 radix_tree_replace_slot(pslot, newpage);
340
343 /*
344 * Now we know that no one else is looking at the page.
345 */
346 get_page(newpage); /* add cache reference */
347#ifdef CONFIG_SWAP
348 if (PageSwapCache(page)) {
349 SetPageSwapCache(newpage);
350 set_page_private(newpage, page_private(page));
351 }
352#endif
353
354 radix_tree_replace_slot(pslot, newpage);
355
356 page_unfreeze_refs(page, expected_count);
341 /*
342 * Drop cache reference from old page.
343 * We know this isn't the last reference.
344 */
345 __put_page(page);
346
347 /*
348 * If moved to a different zone then also account

--- 754 unchanged lines hidden --- 		357 /*
358 * Drop cache reference from old page.
359 * We know this isn't the last reference.
360 */
361 __put_page(page);
362
363 /*
364 * If moved to a different zone then also account

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