extern int mem_cgroup_newpage_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask);
-extern int mem_cgroup_charge_migrate_fixup(struct page *page,
- struct mm_struct *mm, gfp_t gfp_mask);
/* for swap handling */
extern int mem_cgroup_try_charge(struct mm_struct *mm,
gfp_t gfp_mask, struct mem_cgroup **ptr);
((cgroup) == mem_cgroup_from_task((mm)->owner))
extern int
-mem_cgroup_prepare_migration(struct page *page, struct page *newpage);
-extern void mem_cgroup_end_migration(struct page *page);
+mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr);
+extern void mem_cgroup_end_migration(struct mem_cgroup *mem,
+ struct page *oldpage, struct page *newpage);
/*
* For memory reclaim.
return 0;
}
-static inline int mem_cgroup_charge_migrate_fixup(struct page *page,
- struct mm_struct *mm, gfp_t gfp_mask)
-{
- return 0;
-}
-
static inline int mem_cgroup_try_charge(struct mm_struct *mm,
gfp_t gfp_mask, struct mem_cgroup **ptr)
{
}
static inline int
-mem_cgroup_prepare_migration(struct page *page, struct page *newpage)
+mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
{
return 0;
}
-static inline void mem_cgroup_end_migration(struct page *page)
+static inline void mem_cgroup_end_migration(struct mem_cgroup *mem,
+ struct page *oldpage,
+ struct page *newpage)
{
}
MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
}
-/*
- * same as mem_cgroup_newpage_charge(), now.
- * But what we assume is different from newpage, and this is special case.
- * treat this in special function. easy for maintenance.
- */
-
-int mem_cgroup_charge_migrate_fixup(struct page *page,
- struct mm_struct *mm, gfp_t gfp_mask)
-{
- if (mem_cgroup_subsys.disabled)
- return 0;
-
- if (PageCompound(page))
- return 0;
-
- if (page_mapped(page) || (page->mapping && !PageAnon(page)))
- return 0;
-
- if (unlikely(!mm))
- mm = &init_mm;
-
- return mem_cgroup_charge_common(page, mm, gfp_mask,
- MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
-}
-
-
-
-
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask)
{
MEM_CGROUP_CHARGE_TYPE_SHMEM, NULL);
}
-
void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
{
struct page_cgroup *pc;
}
/*
- * Before starting migration, account against new page.
+ * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
+ * page belongs to.
*/
-int mem_cgroup_prepare_migration(struct page *page, struct page *newpage)
+int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
{
struct page_cgroup *pc;
struct mem_cgroup *mem = NULL;
- enum charge_type ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
int ret = 0;
if (mem_cgroup_subsys.disabled)
if (PageCgroupUsed(pc)) {
mem = pc->mem_cgroup;
css_get(&mem->css);
- if (PageCgroupCache(pc)) {
- if (page_is_file_cache(page))
- ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
- else
- ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
- }
}
unlock_page_cgroup(pc);
+
if (mem) {
- ret = mem_cgroup_charge_common(newpage, NULL,
- GFP_HIGHUSER_MOVABLE,
- ctype, mem);
+ ret = mem_cgroup_try_charge(NULL, GFP_HIGHUSER_MOVABLE, &mem);
css_put(&mem->css);
}
+ *ptr = mem;
return ret;
}
/* remove redundant charge if migration failed*/
-void mem_cgroup_end_migration(struct page *newpage)
+void mem_cgroup_end_migration(struct mem_cgroup *mem,
+ struct page *oldpage, struct page *newpage)
{
+ struct page *target, *unused;
+ struct page_cgroup *pc;
+ enum charge_type ctype;
+
+ if (!mem)
+ return;
+
+ /* at migration success, oldpage->mapping is NULL. */
+ if (oldpage->mapping) {
+ target = oldpage;
+ unused = NULL;
+ } else {
+ target = newpage;
+ unused = oldpage;
+ }
+
+ if (PageAnon(target))
+ ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
+ else if (page_is_file_cache(target))
+ ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
+ else
+ ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
+
+ /* unused page is not on radix-tree now. */
+ if (unused && ctype != MEM_CGROUP_CHARGE_TYPE_MAPPED)
+ __mem_cgroup_uncharge_common(unused, ctype);
+
+ pc = lookup_page_cgroup(target);
/*
- * At success, page->mapping is not NULL.
- * special rollback care is necessary when
- * 1. at migration failure. (newpage->mapping is cleared in this case)
- * 2. the newpage was moved but not remapped again because the task
- * exits and the newpage is obsolete. In this case, the new page
- * may be a swapcache. So, we just call mem_cgroup_uncharge_page()
- * always for avoiding mess. The page_cgroup will be removed if
- * unnecessary. File cache pages is still on radix-tree. Don't
- * care it.
+ * __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup.
+ * So, double-counting is effectively avoided.
+ */
+ __mem_cgroup_commit_charge(mem, pc, ctype);
+
+ /*
+ * Both of oldpage and newpage are still under lock_page().
+ * Then, we don't have to care about race in radix-tree.
+ * But we have to be careful that this page is unmapped or not.
+ *
+ * There is a case for !page_mapped(). At the start of
+ * migration, oldpage was mapped. But now, it's zapped.
+ * But we know *target* page is not freed/reused under us.
+ * mem_cgroup_uncharge_page() does all necessary checks.
*/
- if (!newpage->mapping)
- __mem_cgroup_uncharge_common(newpage,
- MEM_CGROUP_CHARGE_TYPE_FORCE);
- else if (PageAnon(newpage))
- mem_cgroup_uncharge_page(newpage);
+ if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
+ mem_cgroup_uncharge_page(target);
}
/*
if (!is_migration_entry(entry) || migration_entry_to_page(entry) != old)
goto out;
- /*
- * Yes, ignore the return value from a GFP_ATOMIC mem_cgroup_charge.
- * Failure is not an option here: we're now expected to remove every
- * migration pte, and will cause crashes otherwise. Normally this
- * is not an issue: mem_cgroup_prepare_migration bumped up the old
- * page_cgroup count for safety, that's now attached to the new page,
- * so this charge should just be another incrementation of the count,
- * to keep in balance with rmap.c's mem_cgroup_uncharging. But if
- * there's been a force_empty, those reference counts may no longer
- * be reliable, and this charge can actually fail: oh well, we don't
- * make the situation any worse by proceeding as if it had succeeded.
- */
- mem_cgroup_charge_migrate_fixup(new, mm, GFP_ATOMIC);
-
get_page(new);
pte = pte_mkold(mk_pte(new, vma->vm_page_prot));
if (is_write_migration_entry(entry))
anon = PageAnon(page);
page->mapping = NULL;
- if (!anon) /* This page was removed from radix-tree. */
- mem_cgroup_uncharge_cache_page(page);
-
/*
* If any waiters have accumulated on the new page then
* wake them up.
struct page *newpage = get_new_page(page, private, &result);
int rcu_locked = 0;
int charge = 0;
+ struct mem_cgroup *mem;
if (!newpage)
return -ENOMEM;
goto move_newpage;
}
- charge = mem_cgroup_prepare_migration(page, newpage);
- if (charge == -ENOMEM) {
- rc = -ENOMEM;
- goto move_newpage;
- }
/* prepare cgroup just returns 0 or -ENOMEM */
- BUG_ON(charge);
-
rc = -EAGAIN;
+
if (!trylock_page(page)) {
if (!force)
goto move_newpage;
lock_page(page);
}
+ /* charge against new page */
+ charge = mem_cgroup_prepare_migration(page, &mem);
+ if (charge == -ENOMEM) {
+ rc = -ENOMEM;
+ goto unlock;
+ }
+ BUG_ON(charge);
+
if (PageWriteback(page)) {
if (!force)
- goto unlock;
+ goto uncharge;
wait_on_page_writeback(page);
}
/*
rcu_unlock:
if (rcu_locked)
rcu_read_unlock();
-
+uncharge:
+ if (!charge)
+ mem_cgroup_end_migration(mem, page, newpage);
unlock:
unlock_page(page);
}
move_newpage:
- if (!charge)
- mem_cgroup_end_migration(newpage);
/*
* Move the new page to the LRU. If migration was not successful
git.openpandora.org / pandora-kernel.git / commitdiff