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-rw-r--r--mm/migrate.c131
1 files changed, 45 insertions, 86 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index 0bc640fd68fa..efddbf0926b2 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -21,6 +21,7 @@
#include <linux/mm_inline.h>
#include <linux/nsproxy.h>
#include <linux/pagevec.h>
+#include <linux/ksm.h>
#include <linux/rmap.h>
#include <linux/topology.h>
#include <linux/cpu.h>
@@ -78,8 +79,8 @@ int putback_lru_pages(struct list_head *l)
/*
* Restore a potential migration pte to a working pte entry
*/
-static void remove_migration_pte(struct vm_area_struct *vma,
- struct page *old, struct page *new)
+static int remove_migration_pte(struct page *new, struct vm_area_struct *vma,
+ unsigned long addr, void *old)
{
struct mm_struct *mm = vma->vm_mm;
swp_entry_t entry;
@@ -88,40 +89,37 @@ static void remove_migration_pte(struct vm_area_struct *vma,
pmd_t *pmd;
pte_t *ptep, pte;
spinlock_t *ptl;
- unsigned long addr = page_address_in_vma(new, vma);
-
- if (addr == -EFAULT)
- return;
pgd = pgd_offset(mm, addr);
if (!pgd_present(*pgd))
- return;
+ goto out;
pud = pud_offset(pgd, addr);
if (!pud_present(*pud))
- return;
+ goto out;
pmd = pmd_offset(pud, addr);
if (!pmd_present(*pmd))
- return;
+ goto out;
ptep = pte_offset_map(pmd, addr);
if (!is_swap_pte(*ptep)) {
pte_unmap(ptep);
- return;
+ goto out;
}
ptl = pte_lockptr(mm, pmd);
spin_lock(ptl);
pte = *ptep;
if (!is_swap_pte(pte))
- goto out;
+ goto unlock;
entry = pte_to_swp_entry(pte);
- if (!is_migration_entry(entry) || migration_entry_to_page(entry) != old)
- goto out;
+ if (!is_migration_entry(entry) ||
+ migration_entry_to_page(entry) != old)
+ goto unlock;
get_page(new);
pte = pte_mkold(mk_pte(new, vma->vm_page_prot));
@@ -137,58 +135,10 @@ static void remove_migration_pte(struct vm_area_struct *vma,
/* No need to invalidate - it was non-present before */
update_mmu_cache(vma, addr, pte);
-
-out:
+unlock:
pte_unmap_unlock(ptep, ptl);
-}
-
-/*
- * Note that remove_file_migration_ptes will only work on regular mappings,
- * Nonlinear mappings do not use migration entries.
- */
-static void remove_file_migration_ptes(struct page *old, struct page *new)
-{
- struct vm_area_struct *vma;
- struct address_space *mapping = new->mapping;
- struct prio_tree_iter iter;
- pgoff_t pgoff = new->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
-
- if (!mapping)
- return;
-
- spin_lock(&mapping->i_mmap_lock);
-
- vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff)
- remove_migration_pte(vma, old, new);
-
- spin_unlock(&mapping->i_mmap_lock);
-}
-
-/*
- * Must hold mmap_sem lock on at least one of the vmas containing
- * the page so that the anon_vma cannot vanish.
- */
-static void remove_anon_migration_ptes(struct page *old, struct page *new)
-{
- struct anon_vma *anon_vma;
- struct vm_area_struct *vma;
- unsigned long mapping;
-
- mapping = (unsigned long)new->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_migration_pte(vma, old, new);
-
- spin_unlock(&anon_vma->lock);
+out:
+ return SWAP_AGAIN;
}
/*
@@ -197,10 +147,7 @@ static void remove_anon_migration_ptes(struct page *old, struct page *new)
*/
static void remove_migration_ptes(struct page *old, struct page *new)
{
- if (PageAnon(new))
- remove_anon_migration_ptes(old, new);
- else
- remove_file_migration_ptes(old, new);
+ rmap_walk(new, remove_migration_pte, old);
}
/*
@@ -341,8 +288,8 @@ static void migrate_page_copy(struct page *newpage, struct page *page)
if (TestClearPageActive(page)) {
VM_BUG_ON(PageUnevictable(page));
SetPageActive(newpage);
- } else
- unevictable_migrate_page(newpage, page);
+ } else if (TestClearPageUnevictable(page))
+ SetPageUnevictable(newpage);
if (PageChecked(page))
SetPageChecked(newpage);
if (PageMappedToDisk(page))
@@ -361,6 +308,7 @@ static void migrate_page_copy(struct page *newpage, struct page *page)
}
mlock_migrate_page(newpage, page);
+ ksm_migrate_page(newpage, page);
ClearPageSwapCache(page);
ClearPagePrivate(page);
@@ -580,9 +528,9 @@ static int move_to_new_page(struct page *newpage, struct page *page)
else
rc = fallback_migrate_page(mapping, newpage, page);
- if (!rc) {
+ if (!rc)
remove_migration_ptes(page, newpage);
- } else
+ else
newpage->mapping = NULL;
unlock_page(newpage);
@@ -595,7 +543,7 @@ static int move_to_new_page(struct page *newpage, struct page *page)
* to the newly allocated page in newpage.
*/
static int unmap_and_move(new_page_t get_new_page, unsigned long private,
- struct page *page, int force)
+ struct page *page, int force, int offlining)
{
int rc = 0;
int *result = NULL;
@@ -621,6 +569,20 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
lock_page(page);
}
+ /*
+ * Only memory hotplug's offline_pages() caller has locked out KSM,
+ * and can safely migrate a KSM page. The other cases have skipped
+ * PageKsm along with PageReserved - but it is only now when we have
+ * the page lock that we can be certain it will not go KSM beneath us
+ * (KSM will not upgrade a page from PageAnon to PageKsm when it sees
+ * its pagecount raised, but only here do we take the page lock which
+ * serializes that).
+ */
+ if (PageKsm(page) && !offlining) {
+ rc = -EBUSY;
+ goto unlock;
+ }
+
/* charge against new page */
charge = mem_cgroup_prepare_migration(page, &mem);
if (charge == -ENOMEM) {
@@ -737,7 +699,7 @@ move_newpage:
* Return: Number of pages not migrated or error code.
*/
int migrate_pages(struct list_head *from,
- new_page_t get_new_page, unsigned long private)
+ new_page_t get_new_page, unsigned long private, int offlining)
{
int retry = 1;
int nr_failed = 0;
@@ -746,13 +708,6 @@ int migrate_pages(struct list_head *from,
struct page *page2;
int swapwrite = current->flags & PF_SWAPWRITE;
int rc;
- unsigned long flags;
-
- local_irq_save(flags);
- list_for_each_entry(page, from, lru)
- __inc_zone_page_state(page, NR_ISOLATED_ANON +
- page_is_file_cache(page));
- local_irq_restore(flags);
if (!swapwrite)
current->flags |= PF_SWAPWRITE;
@@ -764,7 +719,7 @@ int migrate_pages(struct list_head *from,
cond_resched();
rc = unmap_and_move(get_new_page, private,
- page, pass > 2);
+ page, pass > 2, offlining);
switch(rc) {
case -ENOMEM:
@@ -860,7 +815,8 @@ static int do_move_page_to_node_array(struct mm_struct *mm,
if (!page)
goto set_status;
- if (PageReserved(page)) /* Check for zero page */
+ /* Use PageReserved to check for zero page */
+ if (PageReserved(page) || PageKsm(page))
goto put_and_set;
pp->page = page;
@@ -878,8 +834,11 @@ static int do_move_page_to_node_array(struct mm_struct *mm,
goto put_and_set;
err = isolate_lru_page(page);
- if (!err)
+ if (!err) {
list_add_tail(&page->lru, &pagelist);
+ inc_zone_page_state(page, NR_ISOLATED_ANON +
+ page_is_file_cache(page));
+ }
put_and_set:
/*
* Either remove the duplicate refcount from
@@ -894,7 +853,7 @@ set_status:
err = 0;
if (!list_empty(&pagelist))
err = migrate_pages(&pagelist, new_page_node,
- (unsigned long)pm);
+ (unsigned long)pm, 0);
up_read(&mm->mmap_sem);
return err;
@@ -1015,7 +974,7 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
err = -ENOENT;
/* Use PageReserved to check for zero page */
- if (!page || PageReserved(page))
+ if (!page || PageReserved(page) || PageKsm(page))
goto set_status;
err = page_to_nid(page);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-20 09:37:28 +0100