#include <linux/security.h>
#include <linux/memcontrol.h>
#include <linux/syscalls.h>
+#include <linux/gfp.h>
#include "internal.h"
/*
* migrate_prep() needs to be called before we start compiling a list of pages
- * to be migrated using isolate_lru_page().
+ * to be migrated using isolate_lru_page(). If scheduling work on other CPUs is
+ * undesirable, use migrate_prep_local()
*/
int migrate_prep(void)
{
return 0;
}
+/* Do the necessary work of migrate_prep but not if it involves other CPUs */
+int migrate_prep_local(void)
+{
+ lru_add_drain();
+
+ return 0;
+}
+
/*
* Add isolated pages on the list back to the LRU under page lock
* to avoid leaking evictable pages back onto unevictable list.
- *
- * returns the number of pages put back.
*/
-int putback_lru_pages(struct list_head *l)
+void putback_lru_pages(struct list_head *l)
{
struct page *page;
struct page *page2;
- int count = 0;
list_for_each_entry_safe(page, page2, l, lru) {
list_del(&page->lru);
dec_zone_page_state(page, NR_ISOLATED_ANON +
page_is_file_cache(page));
putback_lru_page(page);
- count++;
}
- return count;
}
/*
page_add_file_rmap(new);
/* No need to invalidate - it was non-present before */
- update_mmu_cache(vma, addr, pte);
+ update_mmu_cache(vma, addr, ptep);
unlock:
pte_unmap_unlock(ptep, ptl);
out:
*/
static void migrate_page_copy(struct page *newpage, struct page *page)
{
- int anon;
-
copy_highpage(newpage, page);
if (PageError(page))
ClearPageSwapCache(page);
ClearPagePrivate(page);
set_page_private(page, 0);
- /* page->mapping contains a flag for PageAnon() */
- anon = PageAnon(page);
page->mapping = NULL;
/*
* < 0 - error code
* == 0 - success
*/
-static int move_to_new_page(struct page *newpage, struct page *page)
+static int move_to_new_page(struct page *newpage, struct page *page,
+ int remap_swapcache)
{
struct address_space *mapping;
int rc;
else
rc = fallback_migrate_page(mapping, newpage, page);
- if (!rc)
- remove_migration_ptes(page, newpage);
- else
+ if (rc) {
newpage->mapping = NULL;
+ } else {
+ if (remap_swapcache)
+ remove_migration_ptes(page, newpage);
+ }
unlock_page(newpage);
int rc = 0;
int *result = NULL;
struct page *newpage = get_new_page(page, private, &result);
+ int remap_swapcache = 1;
int rcu_locked = 0;
int charge = 0;
struct mem_cgroup *mem = NULL;
+ struct anon_vma *anon_vma = NULL;
if (!newpage)
return -ENOMEM;
if (PageAnon(page)) {
rcu_read_lock();
rcu_locked = 1;
+
+ /* Determine how to safely use anon_vma */
+ if (!page_mapped(page)) {
+ if (!PageSwapCache(page))
+ goto rcu_unlock;
+
+ /*
+ * We cannot be sure that the anon_vma of an unmapped
+ * swapcache page is safe to use because we don't
+ * know in advance if the VMA that this page belonged
+ * to still exists. If the VMA and others sharing the
+ * data have been freed, then the anon_vma could
+ * already be invalid.
+ *
+ * To avoid this possibility, swapcache pages get
+ * migrated but are not remapped when migration
+ * completes
+ */
+ remap_swapcache = 0;
+ } else {
+ /*
+ * Take a reference count on the anon_vma if the
+ * page is mapped so that it is guaranteed to
+ * exist when the page is remapped later
+ */
+ anon_vma = page_anon_vma(page);
+ atomic_inc(&anon_vma->external_refcount);
+ }
}
/*
skip_unmap:
if (!page_mapped(page))
- rc = move_to_new_page(newpage, page);
+ rc = move_to_new_page(newpage, page, remap_swapcache);
- if (rc)
+ if (rc && remap_swapcache)
remove_migration_ptes(page, page);
rcu_unlock:
+
+ /* Drop an anon_vma reference if we took one */
+ if (anon_vma && atomic_dec_and_lock(&anon_vma->external_refcount, &anon_vma->lock)) {
+ int empty = list_empty(&anon_vma->head);
+ spin_unlock(&anon_vma->lock);
+ if (empty)
+ anon_vma_free(anon_vma);
+ }
+
if (rcu_locked)
rcu_read_unlock();
uncharge:
goto out_pm;
err = -ENODEV;
+ if (node < 0 || node >= MAX_NUMNODES)
+ goto out_pm;
+
if (!node_state(node, N_HIGH_MEMORY))
goto out_pm;
#define DO_PAGES_STAT_CHUNK_NR 16
const void __user *chunk_pages[DO_PAGES_STAT_CHUNK_NR];
int chunk_status[DO_PAGES_STAT_CHUNK_NR];
- unsigned long i, chunk_nr = DO_PAGES_STAT_CHUNK_NR;
- int err;
- for (i = 0; i < nr_pages; i += chunk_nr) {
- if (chunk_nr > nr_pages - i)
- chunk_nr = nr_pages - i;
+ while (nr_pages) {
+ unsigned long chunk_nr;
- err = copy_from_user(chunk_pages, &pages[i],
- chunk_nr * sizeof(*chunk_pages));
- if (err) {
- err = -EFAULT;
- goto out;
- }
+ chunk_nr = nr_pages;
+ if (chunk_nr > DO_PAGES_STAT_CHUNK_NR)
+ chunk_nr = DO_PAGES_STAT_CHUNK_NR;
+
+ if (copy_from_user(chunk_pages, pages, chunk_nr * sizeof(*chunk_pages)))
+ break;
do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status);
- err = copy_to_user(&status[i], chunk_status,
- chunk_nr * sizeof(*chunk_status));
- if (err) {
- err = -EFAULT;
- goto out;
- }
- }
- err = 0;
+ if (copy_to_user(status, chunk_status, chunk_nr * sizeof(*status)))
+ break;
-out:
- return err;
+ pages += chunk_nr;
+ status += chunk_nr;
+ nr_pages -= chunk_nr;
+ }
+ return nr_pages ? -EFAULT : 0;
}
/*