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mm/rmap.c
24.5 KB
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/* * mm/rmap.c - physical to virtual reverse mappings * * Copyright 2001, Rik van Riel <riel@conectiva.com.br> * Released under the General Public License (GPL). * * Simple, low overhead reverse mapping scheme. * Please try to keep this thing as modular as possible. * * Provides methods for unmapping each kind of mapped page: * the anon methods track anonymous pages, and * the file methods track pages belonging to an inode. * * Original design by Rik van Riel <riel@conectiva.com.br> 2001 * File methods by Dave McCracken <dmccr@us.ibm.com> 2003, 2004 * Anonymous methods by Andrea Arcangeli <andrea@suse.de> 2004 * Contributions by Hugh Dickins <hugh@veritas.com> 2003, 2004 */ /* * Lock ordering in mm: * |
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* inode->i_mutex (while writing or truncating, not reading or faulting) |
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* inode->i_alloc_sem * * When a page fault occurs in writing from user to file, down_read |
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* of mmap_sem nests within i_mutex; in sys_msync, i_mutex nests within * down_read of mmap_sem; i_mutex and down_write of mmap_sem are never * taken together; in truncation, i_mutex is taken outermost. |
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* * mm->mmap_sem * page->flags PG_locked (lock_page) * mapping->i_mmap_lock * anon_vma->lock |
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* mm->page_table_lock or pte_lock |
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* zone->lru_lock (in mark_page_accessed, isolate_lru_page) |
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* swap_lock (in swap_duplicate, swap_info_get) |
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* mmlist_lock (in mmput, drain_mmlist and others) |
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* mapping->private_lock (in __set_page_dirty_buffers) * inode_lock (in set_page_dirty's __mark_inode_dirty) * sb_lock (within inode_lock in fs/fs-writeback.c) * mapping->tree_lock (widely used, in set_page_dirty, * in arch-dependent flush_dcache_mmap_lock, * within inode_lock in __sync_single_inode) */ #include <linux/mm.h> #include <linux/pagemap.h> #include <linux/swap.h> #include <linux/swapops.h> #include <linux/slab.h> #include <linux/init.h> #include <linux/rmap.h> #include <linux/rcupdate.h> |
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#include <linux/module.h> |
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#include <asm/tlbflush.h> |
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struct kmem_cache *anon_vma_cachep; |
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static inline void validate_anon_vma(struct vm_area_struct *find_vma) { |
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#ifdef CONFIG_DEBUG_VM |
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struct anon_vma *anon_vma = find_vma->anon_vma; struct vm_area_struct *vma; unsigned int mapcount = 0; int found = 0; list_for_each_entry(vma, &anon_vma->head, anon_vma_node) { mapcount++; BUG_ON(mapcount > 100000); if (vma == find_vma) found = 1; } BUG_ON(!found); #endif } /* This must be called under the mmap_sem. */ int anon_vma_prepare(struct vm_area_struct *vma) { struct anon_vma *anon_vma = vma->anon_vma; might_sleep(); if (unlikely(!anon_vma)) { struct mm_struct *mm = vma->vm_mm; struct anon_vma *allocated, *locked; anon_vma = find_mergeable_anon_vma(vma); if (anon_vma) { allocated = NULL; locked = anon_vma; spin_lock(&locked->lock); } else { anon_vma = anon_vma_alloc(); if (unlikely(!anon_vma)) return -ENOMEM; allocated = anon_vma; locked = NULL; } /* page_table_lock to protect against threads */ spin_lock(&mm->page_table_lock); if (likely(!vma->anon_vma)) { vma->anon_vma = anon_vma; |
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list_add_tail(&vma->anon_vma_node, &anon_vma->head); |
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allocated = NULL; } spin_unlock(&mm->page_table_lock); if (locked) spin_unlock(&locked->lock); if (unlikely(allocated)) anon_vma_free(allocated); } return 0; } void __anon_vma_merge(struct vm_area_struct *vma, struct vm_area_struct *next) { BUG_ON(vma->anon_vma != next->anon_vma); list_del(&next->anon_vma_node); } void __anon_vma_link(struct vm_area_struct *vma) { struct anon_vma *anon_vma = vma->anon_vma; if (anon_vma) { |
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list_add_tail(&vma->anon_vma_node, &anon_vma->head); |
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validate_anon_vma(vma); } } void anon_vma_link(struct vm_area_struct *vma) { struct anon_vma *anon_vma = vma->anon_vma; if (anon_vma) { spin_lock(&anon_vma->lock); |
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list_add_tail(&vma->anon_vma_node, &anon_vma->head); |
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validate_anon_vma(vma); spin_unlock(&anon_vma->lock); } } void anon_vma_unlink(struct vm_area_struct *vma) { struct anon_vma *anon_vma = vma->anon_vma; int empty; if (!anon_vma) return; spin_lock(&anon_vma->lock); validate_anon_vma(vma); list_del(&vma->anon_vma_node); /* We must garbage collect the anon_vma if it's empty */ empty = list_empty(&anon_vma->head); spin_unlock(&anon_vma->lock); if (empty) anon_vma_free(anon_vma); } |
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static void anon_vma_ctor(void *data, struct kmem_cache *cachep, unsigned long flags) |
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{ if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == SLAB_CTOR_CONSTRUCTOR) { struct anon_vma *anon_vma = data; spin_lock_init(&anon_vma->lock); INIT_LIST_HEAD(&anon_vma->head); } } void __init anon_vma_init(void) { anon_vma_cachep = kmem_cache_create("anon_vma", sizeof(struct anon_vma), 0, SLAB_DESTROY_BY_RCU|SLAB_PANIC, anon_vma_ctor, NULL); } /* * Getting a lock on a stable anon_vma from a page off the LRU is * tricky: page_lock_anon_vma rely on RCU to guard against the races. */ static struct anon_vma *page_lock_anon_vma(struct page *page) { struct anon_vma *anon_vma = NULL; unsigned long anon_mapping; rcu_read_lock(); anon_mapping = (unsigned long) page->mapping; if (!(anon_mapping & PAGE_MAPPING_ANON)) goto out; if (!page_mapped(page)) goto out; anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON); spin_lock(&anon_vma->lock); out: rcu_read_unlock(); return anon_vma; } /* * At what user virtual address is page expected in vma? */ static inline unsigned long vma_address(struct page *page, struct vm_area_struct *vma) { pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); unsigned long address; address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); if (unlikely(address < vma->vm_start || address >= vma->vm_end)) { /* page should be within any vma from prio_tree_next */ BUG_ON(!PageAnon(page)); return -EFAULT; } return address; } /* * At what user virtual address is page expected in vma? checking that the |
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* page matches the vma: currently only used on anon pages, by unuse_vma; |
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*/ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma) { if (PageAnon(page)) { if ((void *)vma->anon_vma != (void *)page->mapping - PAGE_MAPPING_ANON) return -EFAULT; } else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) { |
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if (!vma->vm_file || vma->vm_file->f_mapping != page->mapping) |
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return -EFAULT; } else return -EFAULT; return vma_address(page, vma); } /* |
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* Check that @page is mapped at @address into @mm. * |
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* On success returns with pte mapped and locked. |
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*/ |
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pte_t *page_check_address(struct page *page, struct mm_struct *mm, |
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unsigned long address, spinlock_t **ptlp) |
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{ pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t *pte; |
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spinlock_t *ptl; |
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|
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pgd = pgd_offset(mm, address); |
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if (!pgd_present(*pgd)) return NULL; pud = pud_offset(pgd, address); if (!pud_present(*pud)) return NULL; pmd = pmd_offset(pud, address); if (!pmd_present(*pmd)) return NULL; pte = pte_offset_map(pmd, address); /* Make a quick check before getting the lock */ if (!pte_present(*pte)) { pte_unmap(pte); return NULL; } |
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ptl = pte_lockptr(mm, pmd); |
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spin_lock(ptl); if (pte_present(*pte) && page_to_pfn(page) == pte_pfn(*pte)) { *ptlp = ptl; return pte; |
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} |
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pte_unmap_unlock(pte, ptl); return NULL; |
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} /* |
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* Subfunctions of page_referenced: page_referenced_one called * repeatedly from either page_referenced_anon or page_referenced_file. */ static int page_referenced_one(struct page *page, |
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struct vm_area_struct *vma, unsigned int *mapcount) |
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{ struct mm_struct *mm = vma->vm_mm; unsigned long address; |
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pte_t *pte; |
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spinlock_t *ptl; |
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int referenced = 0; |
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address = vma_address(page, vma); if (address == -EFAULT) goto out; |
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pte = page_check_address(page, mm, address, &ptl); if (!pte) goto out; |
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|
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if (ptep_clear_flush_young(vma, address, pte)) referenced++; |
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|
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/* Pretend the page is referenced if the task has the swap token and is in the middle of a page fault. */ |
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if (mm != current->mm && has_swap_token(mm) && |
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rwsem_is_locked(&mm->mmap_sem)) referenced++; (*mapcount)--; pte_unmap_unlock(pte, ptl); |
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out: return referenced; } |
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static int page_referenced_anon(struct page *page) |
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{ unsigned int mapcount; struct anon_vma *anon_vma; struct vm_area_struct *vma; int referenced = 0; anon_vma = page_lock_anon_vma(page); if (!anon_vma) return referenced; mapcount = page_mapcount(page); list_for_each_entry(vma, &anon_vma->head, anon_vma_node) { |
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referenced += page_referenced_one(page, vma, &mapcount); |
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if (!mapcount) break; } spin_unlock(&anon_vma->lock); return referenced; } /** * page_referenced_file - referenced check for object-based rmap * @page: the page we're checking references on. * * For an object-based mapped page, find all the places it is mapped and * check/clear the referenced flag. This is done by following the page->mapping * pointer, then walking the chain of vmas it holds. It returns the number * of references it found. * * This function is only called from page_referenced for object-based pages. */ |
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static int page_referenced_file(struct page *page) |
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{ unsigned int mapcount; struct address_space *mapping = page->mapping; pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); struct vm_area_struct *vma; struct prio_tree_iter iter; int referenced = 0; /* * The caller's checks on page->mapping and !PageAnon have made * sure that this is a file page: the check for page->mapping * excludes the case just before it gets set on an anon page. */ BUG_ON(PageAnon(page)); /* * The page lock not only makes sure that page->mapping cannot * suddenly be NULLified by truncation, it makes sure that the * structure at mapping cannot be freed and reused yet, * so we can safely take mapping->i_mmap_lock. */ BUG_ON(!PageLocked(page)); spin_lock(&mapping->i_mmap_lock); /* * i_mmap_lock does not stabilize mapcount at all, but mapcount * is more likely to be accurate if we note it after spinning. */ mapcount = page_mapcount(page); vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { if ((vma->vm_flags & (VM_LOCKED|VM_MAYSHARE)) == (VM_LOCKED|VM_MAYSHARE)) { referenced++; break; } |
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referenced += page_referenced_one(page, vma, &mapcount); |
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if (!mapcount) break; } spin_unlock(&mapping->i_mmap_lock); return referenced; } /** * page_referenced - test if the page was referenced * @page: the page to test * @is_locked: caller holds lock on the page * * Quick test_and_clear_referenced for all mappings to a page, * returns the number of ptes which referenced the page. */ |
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int page_referenced(struct page *page, int is_locked) |
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{ int referenced = 0; |
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if (page_test_and_clear_young(page)) referenced++; if (TestClearPageReferenced(page)) referenced++; if (page_mapped(page) && page->mapping) { if (PageAnon(page)) |
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referenced += page_referenced_anon(page); |
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else if (is_locked) |
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referenced += page_referenced_file(page); |
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else if (TestSetPageLocked(page)) referenced++; else { if (page->mapping) |
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referenced += page_referenced_file(page); |
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unlock_page(page); } } return referenced; } |
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static int page_mkclean_one(struct page *page, struct vm_area_struct *vma) { struct mm_struct *mm = vma->vm_mm; unsigned long address; pte_t *pte, entry; spinlock_t *ptl; int ret = 0; address = vma_address(page, vma); if (address == -EFAULT) goto out; pte = page_check_address(page, mm, address, &ptl); if (!pte) goto out; if (!pte_dirty(*pte) && !pte_write(*pte)) goto unlock; entry = ptep_get_and_clear(mm, address, pte); entry = pte_mkclean(entry); entry = pte_wrprotect(entry); ptep_establish(vma, address, pte, entry); lazy_mmu_prot_update(entry); ret = 1; unlock: pte_unmap_unlock(pte, ptl); out: return ret; } static int page_mkclean_file(struct address_space *mapping, struct page *page) { pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); struct vm_area_struct *vma; struct prio_tree_iter iter; int ret = 0; BUG_ON(PageAnon(page)); spin_lock(&mapping->i_mmap_lock); vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { if (vma->vm_flags & VM_SHARED) ret += page_mkclean_one(page, vma); } spin_unlock(&mapping->i_mmap_lock); return ret; } int page_mkclean(struct page *page) { int ret = 0; BUG_ON(!PageLocked(page)); if (page_mapped(page)) { struct address_space *mapping = page_mapping(page); if (mapping) ret = page_mkclean_file(mapping, page); } return ret; } |
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/** |
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* page_set_anon_rmap - setup new anonymous rmap * @page: the page to add the mapping to * @vma: the vm area in which the mapping is added * @address: the user virtual address mapped */ static void __page_set_anon_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address) { struct anon_vma *anon_vma = vma->anon_vma; BUG_ON(!anon_vma); anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON; page->mapping = (struct address_space *) anon_vma; page->index = linear_page_index(vma, address); |
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/* * nr_mapped state can be updated without turning off * interrupts because it is not modified via interrupt. */ |
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__inc_zone_page_state(page, NR_ANON_PAGES); |
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} /** |
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* page_add_anon_rmap - add pte mapping to an anonymous page * @page: the page to add the mapping to * @vma: the vm area in which the mapping is added * @address: the user virtual address mapped * |
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* The caller needs to hold the pte lock. |
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*/ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address) { |
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if (atomic_inc_and_test(&page->_mapcount)) __page_set_anon_rmap(page, vma, address); |
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/* else checking page index and mapping is racy */ } |
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/* * page_add_new_anon_rmap - add pte mapping to a new anonymous page * @page: the page to add the mapping to * @vma: the vm area in which the mapping is added * @address: the user virtual address mapped * * Same as page_add_anon_rmap but must only be called on *new* pages. * This means the inc-and-test can be bypassed. */ void page_add_new_anon_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address) { atomic_set(&page->_mapcount, 0); /* elevate count by 1 (starts at -1) */ __page_set_anon_rmap(page, vma, address); } |
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/** * page_add_file_rmap - add pte mapping to a file page * @page: the page to add the mapping to * |
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* The caller needs to hold the pte lock. |
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*/ void page_add_file_rmap(struct page *page) { |
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if (atomic_inc_and_test(&page->_mapcount)) |
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__inc_zone_page_state(page, NR_FILE_MAPPED); |
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} /** * page_remove_rmap - take down pte mapping from a page * @page: page to remove mapping from * |
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* The caller needs to hold the pte lock. |
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*/ void page_remove_rmap(struct page *page) { |
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if (atomic_add_negative(-1, &page->_mapcount)) { |
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if (unlikely(page_mapcount(page) < 0)) { |
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printk (KERN_EMERG "Eeek! page_mapcount(page) went negative! (%d) ", page_mapcount(page)); printk (KERN_EMERG " page->flags = %lx ", page->flags); printk (KERN_EMERG " page->count = %x ", page_count(page)); printk (KERN_EMERG " page->mapping = %p ", page->mapping); |
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BUG(); |
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} |
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|
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/* * It would be tidy to reset the PageAnon mapping here, * but that might overwrite a racing page_add_anon_rmap * which increments mapcount after us but sets mapping * before us: so leave the reset to free_hot_cold_page, * and remember that it's only reliable while mapped. * Leaving it set also helps swapoff to reinstate ptes * faster for those pages still in swapcache. */ if (page_test_and_clear_dirty(page)) set_page_dirty(page); |
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__dec_zone_page_state(page, PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED); |
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} } /* * Subfunctions of try_to_unmap: try_to_unmap_one called * repeatedly from either try_to_unmap_anon or try_to_unmap_file. */ |
a48d07afd [PATCH] Direct Mi... |
599 |
static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, |
7352349a1 [PATCH] page migr... |
600 |
int migration) |
1da177e4c Linux-2.6.12-rc2 |
601 602 603 |
{ struct mm_struct *mm = vma->vm_mm; unsigned long address; |
1da177e4c Linux-2.6.12-rc2 |
604 605 |
pte_t *pte; pte_t pteval; |
c0718806c [PATCH] mm: rmap ... |
606 |
spinlock_t *ptl; |
1da177e4c Linux-2.6.12-rc2 |
607 |
int ret = SWAP_AGAIN; |
1da177e4c Linux-2.6.12-rc2 |
608 609 610 |
address = vma_address(page, vma); if (address == -EFAULT) goto out; |
c0718806c [PATCH] mm: rmap ... |
611 612 |
pte = page_check_address(page, mm, address, &ptl); if (!pte) |
81b4082dc [PATCH] mm: rmap.... |
613 |
goto out; |
1da177e4c Linux-2.6.12-rc2 |
614 615 616 617 618 619 |
/* * If the page is mlock()d, we cannot swap it out. * If it's recently referenced (perhaps page_referenced * skipped over this mm) then we should reactivate it. */ |
e6a1530d6 [PATCH] Allow mig... |
620 621 |
if (!migration && ((vma->vm_flags & VM_LOCKED) || (ptep_clear_flush_young(vma, address, pte)))) { |
1da177e4c Linux-2.6.12-rc2 |
622 623 624 |
ret = SWAP_FAIL; goto out_unmap; } |
1da177e4c Linux-2.6.12-rc2 |
625 626 627 628 629 630 631 |
/* Nuke the page table entry. */ flush_cache_page(vma, address, page_to_pfn(page)); pteval = ptep_clear_flush(vma, address, pte); /* Move the dirty bit to the physical page now the pte is gone. */ if (pte_dirty(pteval)) set_page_dirty(page); |
365e9c87a [PATCH] mm: updat... |
632 633 |
/* Update high watermark before we lower rss */ update_hiwater_rss(mm); |
1da177e4c Linux-2.6.12-rc2 |
634 |
if (PageAnon(page)) { |
4c21e2f24 [PATCH] mm: split... |
635 |
swp_entry_t entry = { .val = page_private(page) }; |
0697212a4 [PATCH] Swapless ... |
636 637 638 639 640 641 642 643 644 645 646 647 648 |
if (PageSwapCache(page)) { /* * Store the swap location in the pte. * See handle_pte_fault() ... */ swap_duplicate(entry); if (list_empty(&mm->mmlist)) { spin_lock(&mmlist_lock); if (list_empty(&mm->mmlist)) list_add(&mm->mmlist, &init_mm.mmlist); spin_unlock(&mmlist_lock); } |
442c9137d [PATCH] More page... |
649 |
dec_mm_counter(mm, anon_rss); |
04e62a29b [PATCH] More page... |
650 |
#ifdef CONFIG_MIGRATION |
0697212a4 [PATCH] Swapless ... |
651 652 653 654 655 656 657 658 |
} else { /* * Store the pfn of the page in a special migration * pte. do_swap_page() will wait until the migration * pte is removed and then restart fault handling. */ BUG_ON(!migration); entry = make_migration_entry(page, pte_write(pteval)); |
04e62a29b [PATCH] More page... |
659 |
#endif |
1da177e4c Linux-2.6.12-rc2 |
660 661 662 |
} set_pte_at(mm, address, pte, swp_entry_to_pte(entry)); BUG_ON(pte_file(*pte)); |
4294621f4 [PATCH] mm: rss =... |
663 |
} else |
04e62a29b [PATCH] More page... |
664 665 666 667 668 669 670 671 |
#ifdef CONFIG_MIGRATION if (migration) { /* Establish migration entry for a file page */ swp_entry_t entry; entry = make_migration_entry(page, pte_write(pteval)); set_pte_at(mm, address, pte, swp_entry_to_pte(entry)); } else #endif |
4294621f4 [PATCH] mm: rss =... |
672 |
dec_mm_counter(mm, file_rss); |
1da177e4c Linux-2.6.12-rc2 |
673 |
|
04e62a29b [PATCH] More page... |
674 |
|
1da177e4c Linux-2.6.12-rc2 |
675 676 677 678 |
page_remove_rmap(page); page_cache_release(page); out_unmap: |
c0718806c [PATCH] mm: rmap ... |
679 |
pte_unmap_unlock(pte, ptl); |
1da177e4c Linux-2.6.12-rc2 |
680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 |
out: return ret; } /* * objrmap doesn't work for nonlinear VMAs because the assumption that * offset-into-file correlates with offset-into-virtual-addresses does not hold. * Consequently, given a particular page and its ->index, we cannot locate the * ptes which are mapping that page without an exhaustive linear search. * * So what this code does is a mini "virtual scan" of each nonlinear VMA which * maps the file to which the target page belongs. The ->vm_private_data field * holds the current cursor into that scan. Successive searches will circulate * around the vma's virtual address space. * * So as more replacement pressure is applied to the pages in a nonlinear VMA, * more scanning pressure is placed against them as well. Eventually pages * will become fully unmapped and are eligible for eviction. * * For very sparsely populated VMAs this is a little inefficient - chances are * there there won't be many ptes located within the scan cluster. In this case * maybe we could scan further - to the end of the pte page, perhaps. */ #define CLUSTER_SIZE min(32*PAGE_SIZE, PMD_SIZE) #define CLUSTER_MASK (~(CLUSTER_SIZE - 1)) static void try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount, struct vm_area_struct *vma) { struct mm_struct *mm = vma->vm_mm; pgd_t *pgd; pud_t *pud; pmd_t *pmd; |
c0718806c [PATCH] mm: rmap ... |
713 |
pte_t *pte; |
1da177e4c Linux-2.6.12-rc2 |
714 |
pte_t pteval; |
c0718806c [PATCH] mm: rmap ... |
715 |
spinlock_t *ptl; |
1da177e4c Linux-2.6.12-rc2 |
716 717 718 |
struct page *page; unsigned long address; unsigned long end; |
1da177e4c Linux-2.6.12-rc2 |
719 |
|
1da177e4c Linux-2.6.12-rc2 |
720 721 722 723 724 725 726 727 728 |
address = (vma->vm_start + cursor) & CLUSTER_MASK; end = address + CLUSTER_SIZE; if (address < vma->vm_start) address = vma->vm_start; if (end > vma->vm_end) end = vma->vm_end; pgd = pgd_offset(mm, address); if (!pgd_present(*pgd)) |
c0718806c [PATCH] mm: rmap ... |
729 |
return; |
1da177e4c Linux-2.6.12-rc2 |
730 731 732 |
pud = pud_offset(pgd, address); if (!pud_present(*pud)) |
c0718806c [PATCH] mm: rmap ... |
733 |
return; |
1da177e4c Linux-2.6.12-rc2 |
734 735 736 |
pmd = pmd_offset(pud, address); if (!pmd_present(*pmd)) |
c0718806c [PATCH] mm: rmap ... |
737 738 739 |
return; pte = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4c Linux-2.6.12-rc2 |
740 |
|
365e9c87a [PATCH] mm: updat... |
741 742 |
/* Update high watermark before we lower rss */ update_hiwater_rss(mm); |
c0718806c [PATCH] mm: rmap ... |
743 |
for (; address < end; pte++, address += PAGE_SIZE) { |
1da177e4c Linux-2.6.12-rc2 |
744 745 |
if (!pte_present(*pte)) continue; |
6aab341e0 mm: re-architect ... |
746 747 |
page = vm_normal_page(vma, address, *pte); BUG_ON(!page || PageAnon(page)); |
1da177e4c Linux-2.6.12-rc2 |
748 749 750 751 752 |
if (ptep_clear_flush_young(vma, address, pte)) continue; /* Nuke the page table entry. */ |
eca351336 [PATCH] Fix missi... |
753 |
flush_cache_page(vma, address, pte_pfn(*pte)); |
1da177e4c Linux-2.6.12-rc2 |
754 755 756 757 758 759 760 761 762 763 764 765 |
pteval = ptep_clear_flush(vma, address, pte); /* If nonlinear, store the file page offset in the pte. */ if (page->index != linear_page_index(vma, address)) set_pte_at(mm, address, pte, pgoff_to_pte(page->index)); /* Move the dirty bit to the physical page now the pte is gone. */ if (pte_dirty(pteval)) set_page_dirty(page); page_remove_rmap(page); page_cache_release(page); |
4294621f4 [PATCH] mm: rss =... |
766 |
dec_mm_counter(mm, file_rss); |
1da177e4c Linux-2.6.12-rc2 |
767 768 |
(*mapcount)--; } |
c0718806c [PATCH] mm: rmap ... |
769 |
pte_unmap_unlock(pte - 1, ptl); |
1da177e4c Linux-2.6.12-rc2 |
770 |
} |
7352349a1 [PATCH] page migr... |
771 |
static int try_to_unmap_anon(struct page *page, int migration) |
1da177e4c Linux-2.6.12-rc2 |
772 773 774 775 776 777 778 779 780 781 |
{ struct anon_vma *anon_vma; struct vm_area_struct *vma; int ret = SWAP_AGAIN; anon_vma = page_lock_anon_vma(page); if (!anon_vma) return ret; list_for_each_entry(vma, &anon_vma->head, anon_vma_node) { |
7352349a1 [PATCH] page migr... |
782 |
ret = try_to_unmap_one(page, vma, migration); |
1da177e4c Linux-2.6.12-rc2 |
783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 |
if (ret == SWAP_FAIL || !page_mapped(page)) break; } spin_unlock(&anon_vma->lock); return ret; } /** * try_to_unmap_file - unmap file page using the object-based rmap method * @page: the page to unmap * * Find all the mappings of a page using the mapping pointer and the vma chains * contained in the address_space struct it points to. * * This function is only called from try_to_unmap for object-based pages. */ |
7352349a1 [PATCH] page migr... |
799 |
static int try_to_unmap_file(struct page *page, int migration) |
1da177e4c Linux-2.6.12-rc2 |
800 801 802 803 804 805 806 807 808 809 810 811 812 |
{ struct address_space *mapping = page->mapping; pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); struct vm_area_struct *vma; struct prio_tree_iter iter; int ret = SWAP_AGAIN; unsigned long cursor; unsigned long max_nl_cursor = 0; unsigned long max_nl_size = 0; unsigned int mapcount; spin_lock(&mapping->i_mmap_lock); vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { |
7352349a1 [PATCH] page migr... |
813 |
ret = try_to_unmap_one(page, vma, migration); |
1da177e4c Linux-2.6.12-rc2 |
814 815 816 817 818 819 820 821 822 |
if (ret == SWAP_FAIL || !page_mapped(page)) goto out; } if (list_empty(&mapping->i_mmap_nonlinear)) goto out; list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) { |
e6a1530d6 [PATCH] Allow mig... |
823 |
if ((vma->vm_flags & VM_LOCKED) && !migration) |
1da177e4c Linux-2.6.12-rc2 |
824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 |
continue; cursor = (unsigned long) vma->vm_private_data; if (cursor > max_nl_cursor) max_nl_cursor = cursor; cursor = vma->vm_end - vma->vm_start; if (cursor > max_nl_size) max_nl_size = cursor; } if (max_nl_size == 0) { /* any nonlinears locked or reserved */ ret = SWAP_FAIL; goto out; } /* * We don't try to search for this page in the nonlinear vmas, * and page_referenced wouldn't have found it anyway. Instead * just walk the nonlinear vmas trying to age and unmap some. * The mapcount of the page we came in with is irrelevant, * but even so use it as a guide to how hard we should try? */ mapcount = page_mapcount(page); if (!mapcount) goto out; cond_resched_lock(&mapping->i_mmap_lock); max_nl_size = (max_nl_size + CLUSTER_SIZE - 1) & CLUSTER_MASK; if (max_nl_cursor == 0) max_nl_cursor = CLUSTER_SIZE; do { list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) { |
e6a1530d6 [PATCH] Allow mig... |
857 |
if ((vma->vm_flags & VM_LOCKED) && !migration) |
1da177e4c Linux-2.6.12-rc2 |
858 859 |
continue; cursor = (unsigned long) vma->vm_private_data; |
839b9685e [PATCH] rmap: don... |
860 |
while ( cursor < max_nl_cursor && |
1da177e4c Linux-2.6.12-rc2 |
861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 |
cursor < vma->vm_end - vma->vm_start) { try_to_unmap_cluster(cursor, &mapcount, vma); cursor += CLUSTER_SIZE; vma->vm_private_data = (void *) cursor; if ((int)mapcount <= 0) goto out; } vma->vm_private_data = (void *) max_nl_cursor; } cond_resched_lock(&mapping->i_mmap_lock); max_nl_cursor += CLUSTER_SIZE; } while (max_nl_cursor <= max_nl_size); /* * Don't loop forever (perhaps all the remaining pages are * in locked vmas). Reset cursor on all unreserved nonlinear * vmas, now forgetting on which ones it had fallen behind. */ |
101d2be76 [PATCH] unpaged: ... |
879 880 |
list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) vma->vm_private_data = NULL; |
1da177e4c Linux-2.6.12-rc2 |
881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 |
out: spin_unlock(&mapping->i_mmap_lock); return ret; } /** * try_to_unmap - try to remove all page table mappings to a page * @page: the page to get unmapped * * Tries to remove all the page table entries which are mapping this * page, used in the pageout path. Caller must hold the page lock. * Return values are: * * SWAP_SUCCESS - we succeeded in removing all mappings * SWAP_AGAIN - we missed a mapping, try again later * SWAP_FAIL - the page is unswappable */ |
7352349a1 [PATCH] page migr... |
898 |
int try_to_unmap(struct page *page, int migration) |
1da177e4c Linux-2.6.12-rc2 |
899 900 |
{ int ret; |
1da177e4c Linux-2.6.12-rc2 |
901 902 903 |
BUG_ON(!PageLocked(page)); if (PageAnon(page)) |
7352349a1 [PATCH] page migr... |
904 |
ret = try_to_unmap_anon(page, migration); |
1da177e4c Linux-2.6.12-rc2 |
905 |
else |
7352349a1 [PATCH] page migr... |
906 |
ret = try_to_unmap_file(page, migration); |
1da177e4c Linux-2.6.12-rc2 |
907 908 909 910 911 |
if (!page_mapped(page)) ret = SWAP_SUCCESS; return ret; } |
81b4082dc [PATCH] mm: rmap.... |
912 |