/*
* Lock ordering in mm:
*
- * inode->i_sem (while writing or truncating, not reading or faulting)
+ * inode->i_mutex (while writing or truncating, not reading or faulting)
* inode->i_alloc_sem
*
* When a page fault occurs in writing from user to file, down_read
- * of mmap_sem nests within i_sem; in sys_msync, i_sem nests within
- * down_read of mmap_sem; i_sem and down_write of mmap_sem are never
- * taken together; in truncation, i_sem is taken outermost.
+ * 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.
*
* mm->mmap_sem
* page->flags PG_locked (lock_page)
* mapping->i_mmap_lock
* anon_vma->lock
- * mm->page_table_lock
- * zone->lru_lock (in mark_page_accessed)
- * swap_list_lock (in swap_free etc's swap_info_get)
+ * mm->page_table_lock or pte_lock
+ * zone->lru_lock (in mark_page_accessed, isolate_lru_page)
+ * swap_lock (in swap_duplicate, swap_info_get)
* mmlist_lock (in mmput, drain_mmlist and others)
- * swap_device_lock (in swap_duplicate, swap_info_get)
* 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)
#include <linux/init.h>
#include <linux/rmap.h>
#include <linux/rcupdate.h>
+#include <linux/module.h>
#include <linux/vs_memory.h>
#include <asm/tlbflush.h>
-//#define RMAP_DEBUG /* can be enabled only for debugging */
-
-kmem_cache_t *anon_vma_cachep;
+struct kmem_cache *anon_vma_cachep;
static inline void validate_anon_vma(struct vm_area_struct *find_vma)
{
-#ifdef RMAP_DEBUG
+#ifdef CONFIG_DEBUG_VM
struct anon_vma *anon_vma = find_vma->anon_vma;
struct vm_area_struct *vma;
unsigned int mapcount = 0;
anon_vma_free(anon_vma);
}
-static void anon_vma_ctor(void *data, kmem_cache_t *cachep, unsigned long flags)
+static void anon_vma_ctor(void *data, struct kmem_cache *cachep,
+ unsigned long flags)
{
if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
SLAB_CTOR_CONSTRUCTOR) {
return anon_vma;
}
+#ifdef CONFIG_MIGRATION
+/*
+ * Remove an anonymous page from swap replacing the swap pte's
+ * through real pte's pointing to valid pages and then releasing
+ * the page from the swap cache.
+ *
+ * Must hold page lock on page and mmap_sem of one vma that contains
+ * the page.
+ */
+void remove_from_swap(struct page *page)
+{
+ struct anon_vma *anon_vma;
+ struct vm_area_struct *vma;
+ unsigned long mapping;
+
+ if (!PageSwapCache(page))
+ return;
+
+ mapping = (unsigned long)page->mapping;
+
+ if (!mapping || (mapping & PAGE_MAPPING_ANON) == 0)
+ return;
+
+ /*
+ * We hold the mmap_sem lock. So no need to call page_lock_anon_vma.
+ */
+ anon_vma = (struct anon_vma *) (mapping - PAGE_MAPPING_ANON);
+ spin_lock(&anon_vma->lock);
+
+ list_for_each_entry(vma, &anon_vma->head, anon_vma_node)
+ remove_vma_swap(vma, page);
+
+ spin_unlock(&anon_vma->lock);
+ delete_from_swap_cache(page);
+}
+EXPORT_SYMBOL(remove_from_swap);
+#endif
+
/*
* At what user virtual address is page expected in vma?
*/
/*
* At what user virtual address is page expected in vma? checking that the
- * page matches the vma: currently only used by unuse_process, on anon pages.
+ * page matches the vma: currently only used on anon pages, by unuse_vma;
*/
unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
{
(void *)page->mapping - PAGE_MAPPING_ANON)
return -EFAULT;
} else if (page->mapping && !(vma->vm_flags & VM_NONLINEAR)) {
- if (vma->vm_file->f_mapping != page->mapping)
+ if (!vma->vm_file ||
+ vma->vm_file->f_mapping != page->mapping)
return -EFAULT;
} else
return -EFAULT;
/*
* Check that @page is mapped at @address into @mm.
*
- * On success returns with mapped pte and locked mm->page_table_lock.
+ * On success returns with pte mapped and locked.
*/
-static pte_t *page_check_address(struct page *page, struct mm_struct *mm,
- unsigned long address)
+pte_t *page_check_address(struct page *page, struct mm_struct *mm,
+ unsigned long address, spinlock_t **ptlp)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
+ spinlock_t *ptl;
- /*
- * We need the page_table_lock to protect us from page faults,
- * munmap, fork, etc...
- */
- spin_lock(&mm->page_table_lock);
pgd = pgd_offset(mm, address);
- if (likely(pgd_present(*pgd))) {
- pud = pud_offset(pgd, address);
- if (likely(pud_present(*pud))) {
- pmd = pmd_offset(pud, address);
- if (likely(pmd_present(*pmd))) {
- pte = pte_offset_map(pmd, address);
- if (likely(pte_present(*pte) &&
- page_to_pfn(page) == pte_pfn(*pte)))
- return pte;
- pte_unmap(pte);
- }
- }
+ 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;
+ }
+
+ ptl = pte_lockptr(mm, pmd);
+ spin_lock(ptl);
+ if (pte_present(*pte) && page_to_pfn(page) == pte_pfn(*pte)) {
+ *ptlp = ptl;
+ return pte;
}
- spin_unlock(&mm->page_table_lock);
- return ERR_PTR(-ENOENT);
+ pte_unmap_unlock(pte, ptl);
+ return NULL;
}
/*
* repeatedly from either page_referenced_anon or page_referenced_file.
*/
static int page_referenced_one(struct page *page,
- struct vm_area_struct *vma, unsigned int *mapcount, int ignore_token)
+ struct vm_area_struct *vma, unsigned int *mapcount)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long address;
pte_t *pte;
+ spinlock_t *ptl;
int referenced = 0;
- if (!get_mm_counter(mm, rss))
- goto out;
address = vma_address(page, vma);
if (address == -EFAULT)
goto out;
- pte = page_check_address(page, mm, address);
- if (!IS_ERR(pte)) {
- if (ptep_clear_flush_young(vma, address, pte))
- referenced++;
+ pte = page_check_address(page, mm, address, &ptl);
+ if (!pte)
+ goto out;
- if (mm != current->mm && !ignore_token && has_swap_token(mm))
- referenced++;
+ if (ptep_clear_flush_young(vma, address, pte))
+ referenced++;
- (*mapcount)--;
- pte_unmap(pte);
- spin_unlock(&mm->page_table_lock);
- }
+ /* Pretend the page is referenced if the task has the
+ swap token and is in the middle of a page fault. */
+ if (mm != current->mm && has_swap_token(mm) &&
+ rwsem_is_locked(&mm->mmap_sem))
+ referenced++;
+
+ (*mapcount)--;
+ pte_unmap_unlock(pte, ptl);
out:
return referenced;
}
-static int page_referenced_anon(struct page *page, int ignore_token)
+static int page_referenced_anon(struct page *page)
{
unsigned int mapcount;
struct anon_vma *anon_vma;
mapcount = page_mapcount(page);
list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {
- referenced += page_referenced_one(page, vma, &mapcount,
- ignore_token);
+ referenced += page_referenced_one(page, vma, &mapcount);
if (!mapcount)
break;
}
*
* This function is only called from page_referenced for object-based pages.
*/
-static int page_referenced_file(struct page *page, int ignore_token)
+static int page_referenced_file(struct page *page)
{
unsigned int mapcount;
struct address_space *mapping = page->mapping;
referenced++;
break;
}
- referenced += page_referenced_one(page, vma, &mapcount,
- ignore_token);
+ referenced += page_referenced_one(page, vma, &mapcount);
if (!mapcount)
break;
}
* Quick test_and_clear_referenced for all mappings to a page,
* returns the number of ptes which referenced the page.
*/
-int page_referenced(struct page *page, int is_locked, int ignore_token)
+int page_referenced(struct page *page, int is_locked)
{
int referenced = 0;
- if (!swap_token_default_timeout)
- ignore_token = 1;
-
if (page_test_and_clear_young(page))
referenced++;
if (page_mapped(page) && page->mapping) {
if (PageAnon(page))
- referenced += page_referenced_anon(page, ignore_token);
+ referenced += page_referenced_anon(page);
else if (is_locked)
- referenced += page_referenced_file(page, ignore_token);
+ referenced += page_referenced_file(page);
else if (TestSetPageLocked(page))
referenced++;
else {
if (page->mapping)
- referenced += page_referenced_file(page,
- ignore_token);
+ referenced += page_referenced_file(page);
unlock_page(page);
}
}
}
/**
- * page_add_anon_rmap - add pte mapping to an anonymous page
+ * 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
- *
- * The caller needs to hold the mm->page_table_lock.
*/
-void page_add_anon_rmap(struct page *page,
+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;
- pgoff_t index;
- BUG_ON(PageReserved(page));
BUG_ON(!anon_vma);
+ anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
+ page->mapping = (struct address_space *) anon_vma;
- inc_mm_counter(vma->vm_mm, anon_rss);
+ page->index = linear_page_index(vma, address);
- anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
- index = (address - vma->vm_start) >> PAGE_SHIFT;
- index += vma->vm_pgoff;
- index >>= PAGE_CACHE_SHIFT - PAGE_SHIFT;
-
- if (atomic_inc_and_test(&page->_mapcount)) {
- page->index = index;
- page->mapping = (struct address_space *) anon_vma;
- inc_page_state(nr_mapped);
- }
+ /*
+ * nr_mapped state can be updated without turning off
+ * interrupts because it is not modified via interrupt.
+ */
+ __inc_page_state(nr_mapped);
+}
+
+/**
+ * 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
+ *
+ * The caller needs to hold the pte lock.
+ */
+void page_add_anon_rmap(struct page *page,
+ struct vm_area_struct *vma, unsigned long address)
+{
+ if (atomic_inc_and_test(&page->_mapcount))
+ __page_set_anon_rmap(page, vma, address);
/* else checking page index and mapping is racy */
}
+/*
+ * 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);
+}
+
/**
* page_add_file_rmap - add pte mapping to a file page
* @page: the page to add the mapping to
*
- * The caller needs to hold the mm->page_table_lock.
+ * The caller needs to hold the pte lock.
*/
void page_add_file_rmap(struct page *page)
{
- BUG_ON(PageAnon(page));
- if (!pfn_valid(page_to_pfn(page)) || PageReserved(page))
- return;
-
if (atomic_inc_and_test(&page->_mapcount))
- inc_page_state(nr_mapped);
+ __inc_page_state(nr_mapped);
}
/**
* page_remove_rmap - take down pte mapping from a page
* @page: page to remove mapping from
*
- * Caller needs to hold the mm->page_table_lock.
+ * The caller needs to hold the pte lock.
*/
void page_remove_rmap(struct page *page)
{
- BUG_ON(PageReserved(page));
-
if (atomic_add_negative(-1, &page->_mapcount)) {
+#ifdef CONFIG_DEBUG_VM
+ if (unlikely(page_mapcount(page) < 0)) {
+ printk (KERN_EMERG "Eeek! page_mapcount(page) went negative! (%d)\n", page_mapcount(page));
+ printk (KERN_EMERG " page->flags = %lx\n", page->flags);
+ printk (KERN_EMERG " page->count = %x\n", page_count(page));
+ printk (KERN_EMERG " page->mapping = %p\n", page->mapping);
+ }
+#endif
BUG_ON(page_mapcount(page) < 0);
/*
* It would be tidy to reset the PageAnon mapping here,
*/
if (page_test_and_clear_dirty(page))
set_page_dirty(page);
- dec_page_state(nr_mapped);
+ __dec_page_state(nr_mapped);
}
}
* Subfunctions of try_to_unmap: try_to_unmap_one called
* repeatedly from either try_to_unmap_anon or try_to_unmap_file.
*/
-static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
+static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
+ int ignore_refs)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long address;
pte_t *pte;
pte_t pteval;
+ spinlock_t *ptl;
int ret = SWAP_AGAIN;
- if (!get_mm_counter(mm, rss))
- goto out;
address = vma_address(page, vma);
if (address == -EFAULT)
goto out;
- pte = page_check_address(page, mm, address);
- if (IS_ERR(pte))
+ pte = page_check_address(page, mm, address, &ptl);
+ if (!pte)
goto out;
/*
* If it's recently referenced (perhaps page_referenced
* skipped over this mm) then we should reactivate it.
*/
- if ((vma->vm_flags & (VM_LOCKED|VM_RESERVED)) ||
- ptep_clear_flush_young(vma, address, pte)) {
- ret = SWAP_FAIL;
- goto out_unmap;
- }
-
- /*
- * Don't pull an anonymous page out from under get_user_pages.
- * GUP carefully breaks COW and raises page count (while holding
- * page_table_lock, as we have here) to make sure that the page
- * cannot be freed. If we unmap that page here, a user write
- * access to the virtual address will bring back the page, but
- * its raised count will (ironically) be taken to mean it's not
- * an exclusive swap page, do_wp_page will replace it by a copy
- * page, and the user never get to see the data GUP was holding
- * the original page for.
- *
- * This test is also useful for when swapoff (unuse_process) has
- * to drop page lock: its reference to the page stops existing
- * ptes from being unmapped, so swapoff can make progress.
- */
- if (PageSwapCache(page) &&
- page_count(page) != page_mapcount(page) + 2) {
+ if ((vma->vm_flags & VM_LOCKED) ||
+ (ptep_clear_flush_young(vma, address, pte)
+ && !ignore_refs)) {
ret = SWAP_FAIL;
goto out_unmap;
}
if (pte_dirty(pteval))
set_page_dirty(page);
+ /* Update high watermark before we lower rss */
+ update_hiwater_rss(mm);
+
if (PageAnon(page)) {
- swp_entry_t entry = { .val = page->private };
+ swp_entry_t entry = { .val = page_private(page) };
/*
* Store the swap location in the pte.
* See handle_pte_fault() ...
swap_duplicate(entry);
if (list_empty(&mm->mmlist)) {
spin_lock(&mmlist_lock);
- list_add(&mm->mmlist, &init_mm.mmlist);
+ if (list_empty(&mm->mmlist))
+ list_add(&mm->mmlist, &init_mm.mmlist);
spin_unlock(&mmlist_lock);
}
set_pte_at(mm, address, pte, swp_entry_to_pte(entry));
BUG_ON(pte_file(*pte));
dec_mm_counter(mm, anon_rss);
- }
+ } else
+ dec_mm_counter(mm, file_rss);
- dec_mm_counter(mm, rss);
page_remove_rmap(page);
page_cache_release(page);
out_unmap:
- pte_unmap(pte);
- spin_unlock(&mm->page_table_lock);
+ pte_unmap_unlock(pte, ptl);
out:
return ret;
}
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
- pte_t *pte, *original_pte;
+ pte_t *pte;
pte_t pteval;
+ spinlock_t *ptl;
struct page *page;
unsigned long address;
unsigned long end;
- unsigned long pfn;
-
- /*
- * We need the page_table_lock to protect us from page faults,
- * munmap, fork, etc...
- */
- spin_lock(&mm->page_table_lock);
address = (vma->vm_start + cursor) & CLUSTER_MASK;
end = address + CLUSTER_SIZE;
pgd = pgd_offset(mm, address);
if (!pgd_present(*pgd))
- goto out_unlock;
+ return;
pud = pud_offset(pgd, address);
if (!pud_present(*pud))
- goto out_unlock;
+ return;
pmd = pmd_offset(pud, address);
if (!pmd_present(*pmd))
- goto out_unlock;
-
- for (original_pte = pte = pte_offset_map(pmd, address);
- address < end; pte++, address += PAGE_SIZE) {
+ return;
- if (!pte_present(*pte))
- continue;
+ pte = pte_offset_map_lock(mm, pmd, address, &ptl);
- pfn = pte_pfn(*pte);
- if (!pfn_valid(pfn))
- continue;
+ /* Update high watermark before we lower rss */
+ update_hiwater_rss(mm);
- page = pfn_to_page(pfn);
- BUG_ON(PageAnon(page));
- if (PageReserved(page))
+ for (; address < end; pte++, address += PAGE_SIZE) {
+ if (!pte_present(*pte))
continue;
+ page = vm_normal_page(vma, address, *pte);
+ BUG_ON(!page || PageAnon(page));
if (ptep_clear_flush_young(vma, address, pte))
continue;
/* Nuke the page table entry. */
- flush_cache_page(vma, address, pfn);
+ flush_cache_page(vma, address, pte_pfn(*pte));
pteval = ptep_clear_flush(vma, address, pte);
/* If nonlinear, store the file page offset in the pte. */
page_remove_rmap(page);
page_cache_release(page);
- dec_mm_counter(mm, rss);
+ dec_mm_counter(mm, file_rss);
(*mapcount)--;
}
-
- pte_unmap(original_pte);
-out_unlock:
- spin_unlock(&mm->page_table_lock);
+ pte_unmap_unlock(pte - 1, ptl);
}
-static int try_to_unmap_anon(struct page *page)
+static int try_to_unmap_anon(struct page *page, int ignore_refs)
{
struct anon_vma *anon_vma;
struct vm_area_struct *vma;
return ret;
list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {
- ret = try_to_unmap_one(page, vma);
+ ret = try_to_unmap_one(page, vma, ignore_refs);
if (ret == SWAP_FAIL || !page_mapped(page))
break;
}
*
* This function is only called from try_to_unmap for object-based pages.
*/
-static int try_to_unmap_file(struct page *page)
+static int try_to_unmap_file(struct page *page, int ignore_refs)
{
struct address_space *mapping = page->mapping;
pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
spin_lock(&mapping->i_mmap_lock);
vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
- ret = try_to_unmap_one(page, vma);
+ ret = try_to_unmap_one(page, vma, ignore_refs);
if (ret == SWAP_FAIL || !page_mapped(page))
goto out;
}
list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
shared.vm_set.list) {
- if (vma->vm_flags & (VM_LOCKED|VM_RESERVED))
+ if (vma->vm_flags & VM_LOCKED)
continue;
cursor = (unsigned long) vma->vm_private_data;
if (cursor > max_nl_cursor)
do {
list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
shared.vm_set.list) {
- if (vma->vm_flags & (VM_LOCKED|VM_RESERVED))
+ if (vma->vm_flags & VM_LOCKED)
continue;
cursor = (unsigned long) vma->vm_private_data;
- while (get_mm_counter(vma->vm_mm, rss) &&
- cursor < max_nl_cursor &&
+ while ( cursor < max_nl_cursor &&
cursor < vma->vm_end - vma->vm_start) {
try_to_unmap_cluster(cursor, &mapcount, vma);
cursor += CLUSTER_SIZE;
* in locked vmas). Reset cursor on all unreserved nonlinear
* vmas, now forgetting on which ones it had fallen behind.
*/
- list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
- shared.vm_set.list) {
- if (!(vma->vm_flags & VM_RESERVED))
- vma->vm_private_data = NULL;
- }
+ list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
+ vma->vm_private_data = NULL;
out:
spin_unlock(&mapping->i_mmap_lock);
return ret;
* SWAP_AGAIN - we missed a mapping, try again later
* SWAP_FAIL - the page is unswappable
*/
-int try_to_unmap(struct page *page)
+int try_to_unmap(struct page *page, int ignore_refs)
{
int ret;
- BUG_ON(PageReserved(page));
BUG_ON(!PageLocked(page));
if (PageAnon(page))
- ret = try_to_unmap_anon(page);
+ ret = try_to_unmap_anon(page, ignore_refs);
else
- ret = try_to_unmap_file(page);
+ ret = try_to_unmap_file(page, ignore_refs);
if (!page_mapped(page))
ret = SWAP_SUCCESS;
git://git.onelab.eu / linux-2.6.git / blobdiff