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Diffstat (limited to 'mm/rmap.c')
-rw-r--r--mm/rmap.c146
1 files changed, 74 insertions, 72 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index 450f5241b5a5..914d04b98bee 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -32,7 +32,7 @@
* page->flags PG_locked (lock_page)
* mapping->i_mmap_lock
* anon_vma->lock
- * mm->page_table_lock
+ * mm->page_table_lock or pte_lock
* zone->lru_lock (in mark_page_accessed)
* swap_lock (in swap_duplicate, swap_info_get)
* mmlist_lock (in mmput, drain_mmlist and others)
@@ -244,37 +244,44 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
/*
* 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.
*/
pte_t *page_check_address(struct page *page, struct mm_struct *mm,
- unsigned long address)
+ 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;
}
/*
@@ -287,24 +294,28 @@ static int page_referenced_one(struct page *page,
struct mm_struct *mm = vma->vm_mm;
unsigned long address;
pte_t *pte;
+ spinlock_t *ptl;
int referenced = 0;
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 && !ignore_token && has_swap_token(mm) &&
+ rwsem_is_locked(&mm->mmap_sem))
+ referenced++;
+
+ (*mapcount)--;
+ pte_unmap_unlock(pte, ptl);
out:
return referenced;
}
@@ -434,15 +445,11 @@ int page_referenced(struct page *page, int is_locked, int ignore_token)
* @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.
+ * The caller needs to hold the pte lock.
*/
void page_add_anon_rmap(struct page *page,
struct vm_area_struct *vma, unsigned long address)
{
- BUG_ON(PageReserved(page));
-
- inc_mm_counter(vma->vm_mm, anon_rss);
-
if (atomic_inc_and_test(&page->_mapcount)) {
struct anon_vma *anon_vma = vma->anon_vma;
@@ -461,13 +468,12 @@ void page_add_anon_rmap(struct page *page,
* 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;
+ BUG_ON(!pfn_valid(page_to_pfn(page)));
if (atomic_inc_and_test(&page->_mapcount))
inc_page_state(nr_mapped);
@@ -477,12 +483,10 @@ void page_add_file_rmap(struct page *page)
* 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)) {
BUG_ON(page_mapcount(page) < 0);
/*
@@ -510,14 +514,15 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
unsigned long address;
pte_t *pte;
pte_t pteval;
+ spinlock_t *ptl;
int ret = SWAP_AGAIN;
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;
/*
@@ -541,8 +546,11 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
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() ...
@@ -551,21 +559,21 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma)
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;
}
@@ -599,19 +607,14 @@ static void try_to_unmap_cluster(unsigned long cursor,
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;
if (address < vma->vm_start)
@@ -621,30 +624,33 @@ static void try_to_unmap_cluster(unsigned long cursor,
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;
+ return;
+
+ pte = pte_offset_map_lock(mm, pmd, address, &ptl);
- for (original_pte = pte = pte_offset_map(pmd, address);
- address < end; pte++, address += PAGE_SIZE) {
+ /* Update high watermark before we lower rss */
+ update_hiwater_rss(mm);
+ for (; address < end; pte++, address += PAGE_SIZE) {
if (!pte_present(*pte))
continue;
pfn = pte_pfn(*pte);
- if (!pfn_valid(pfn))
+ if (unlikely(!pfn_valid(pfn))) {
+ print_bad_pte(vma, *pte, address);
continue;
+ }
page = pfn_to_page(pfn);
BUG_ON(PageAnon(page));
- if (PageReserved(page))
- continue;
if (ptep_clear_flush_young(vma, address, pte))
continue;
@@ -663,13 +669,10 @@ static void try_to_unmap_cluster(unsigned long cursor,
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)
@@ -806,7 +809,6 @@ int try_to_unmap(struct page *page)
{
int ret;
- BUG_ON(PageReserved(page));
BUG_ON(!PageLocked(page));
if (PageAnon(page))