struct list_head lru; /* per cgroup LRU list */
struct page *page;
struct mem_cgroup *mem_cgroup;
- int ref_cnt; /* cached, mapped, migrating */
int flags;
};
#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */
enum charge_type {
MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
MEM_CGROUP_CHARGE_TYPE_MAPPED,
+ MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
};
/*
*/
if (pc) {
VM_BUG_ON(pc->page != page);
- VM_BUG_ON(pc->ref_cnt <= 0);
-
- pc->ref_cnt++;
+ VM_BUG_ON(!pc->mem_cgroup);
unlock_page_cgroup(page);
goto done;
}
* thread group leader migrates. It's possible that mm is not
* set, if so charge the init_mm (happens for pagecache usage).
*/
- if (!memcg) {
- if (!mm)
- mm = &init_mm;
-
+ if (likely(!memcg)) {
rcu_read_lock();
mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
/*
}
}
- pc->ref_cnt = 1;
pc->mem_cgroup = mem;
pc->page = page;
/*
int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
{
+ /*
+ * If already mapped, we don't have to account.
+ * If page cache, page->mapping has address_space.
+ * But page->mapping may have out-of-use anon_vma pointer,
+ * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
+ * is NULL.
+ */
+ 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)
{
- if (!mm)
+ if (unlikely(!mm))
mm = &init_mm;
return mem_cgroup_charge_common(page, mm, gfp_mask,
MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
}
-int mem_cgroup_getref(struct page *page)
-{
- struct page_cgroup *pc;
-
- if (mem_cgroup_subsys.disabled)
- return 0;
-
- lock_page_cgroup(page);
- pc = page_get_page_cgroup(page);
- VM_BUG_ON(!pc);
- pc->ref_cnt++;
- unlock_page_cgroup(page);
- return 0;
-}
-
/*
- * Uncharging is always a welcome operation, we never complain, simply
- * uncharge.
+ * uncharge if !page_mapped(page)
*/
-void mem_cgroup_uncharge_page(struct page *page)
+static void
+__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
{
struct page_cgroup *pc;
struct mem_cgroup *mem;
goto unlock;
VM_BUG_ON(pc->page != page);
- VM_BUG_ON(pc->ref_cnt <= 0);
- if (--(pc->ref_cnt) == 0) {
- mz = page_cgroup_zoneinfo(pc);
- spin_lock_irqsave(&mz->lru_lock, flags);
- __mem_cgroup_remove_list(mz, pc);
- spin_unlock_irqrestore(&mz->lru_lock, flags);
+ if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
+ && ((pc->flags & PAGE_CGROUP_FLAG_CACHE)
+ || page_mapped(page)))
+ goto unlock;
- page_assign_page_cgroup(page, NULL);
- unlock_page_cgroup(page);
+ mz = page_cgroup_zoneinfo(pc);
+ spin_lock_irqsave(&mz->lru_lock, flags);
+ __mem_cgroup_remove_list(mz, pc);
+ spin_unlock_irqrestore(&mz->lru_lock, flags);
- mem = pc->mem_cgroup;
- res_counter_uncharge(&mem->res, PAGE_SIZE);
- css_put(&mem->css);
+ page_assign_page_cgroup(page, NULL);
+ unlock_page_cgroup(page);
- kmem_cache_free(page_cgroup_cache, pc);
- return;
- }
+ mem = pc->mem_cgroup;
+ res_counter_uncharge(&mem->res, PAGE_SIZE);
+ css_put(&mem->css);
+ kmem_cache_free(page_cgroup_cache, pc);
+ return;
unlock:
unlock_page_cgroup(page);
}
+void mem_cgroup_uncharge_page(struct page *page)
+{
+ __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
+}
+
+void mem_cgroup_uncharge_cache_page(struct page *page)
+{
+ VM_BUG_ON(page_mapped(page));
+ __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
+}
+
/*
* Before starting migration, account against new page.
*/
return ret;
}
-/* remove redundant charge */
+/* remove redundant charge if migration failed*/
void mem_cgroup_end_migration(struct page *newpage)
{
- mem_cgroup_uncharge_page(newpage);
+ /*
+ * 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.
+ */
+ if (!newpage->mapping)
+ __mem_cgroup_uncharge_common(newpage,
+ MEM_CGROUP_CHARGE_TYPE_FORCE);
+ else if (PageAnon(newpage))
+ mem_cgroup_uncharge_page(newpage);
}
/*
* This routine traverse page_cgroup in given list and drop them all.
- * This routine ignores page_cgroup->ref_cnt.
* *And* this routine doesn't reclaim page itself, just removes page_cgroup.
*/
#define FORCE_UNCHARGE_BATCH (128)
* if it's under page migration.
*/
if (PageLRU(page)) {
- mem_cgroup_uncharge_page(page);
+ __mem_cgroup_uncharge_common(page,
+ MEM_CGROUP_CHARGE_TYPE_FORCE);
put_page(page);
if (--count <= 0) {
count = FORCE_UNCHARGE_BATCH;
error = 1;
if (!inode)
goto out;
- /* Precharge page while we can wait, compensate afterwards */
+ /* Precharge page using GFP_KERNEL while we can wait */
error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL);
if (error)
goto out;
error = radix_tree_preload(GFP_KERNEL);
- if (error)
- goto uncharge;
+ if (error) {
+ mem_cgroup_uncharge_cache_page(page);
+ goto out;
+ }
error = 1;
spin_lock(&info->lock);
ptr = shmem_swp_entry(info, idx, NULL);
- if (ptr && ptr->val == entry.val)
+ if (ptr && ptr->val == entry.val) {
error = add_to_page_cache(page, inode->i_mapping,
idx, GFP_NOWAIT);
+ /* does mem_cgroup_uncharge_cache_page on error */
+ } else /* we must compensate for our precharge above */
+ mem_cgroup_uncharge_cache_page(page);
+
if (error == -EEXIST) {
struct page *filepage = find_get_page(inode->i_mapping, idx);
error = 1;
shmem_swp_unmap(ptr);
spin_unlock(&info->lock);
radix_tree_preload_end();
-uncharge:
- mem_cgroup_uncharge_page(page);
out:
unlock_page(page);
page_cache_release(page);
page_cache_release(swappage);
goto failed;
}
- mem_cgroup_uncharge_page(swappage);
+ mem_cgroup_uncharge_cache_page(swappage);
}
page_cache_release(swappage);
goto repeat;
}
if (!filepage) {
+ int ret;
+
spin_unlock(&info->lock);
filepage = shmem_alloc_page(gfp, info, idx);
if (!filepage) {
swap = *entry;
shmem_swp_unmap(entry);
}
- if (error || swap.val || 0 != add_to_page_cache_lru(
- filepage, mapping, idx, GFP_NOWAIT)) {
+ ret = error || swap.val;
+ if (ret)
+ mem_cgroup_uncharge_cache_page(filepage);
+ else
+ ret = add_to_page_cache_lru(filepage, mapping,
+ idx, GFP_NOWAIT);
+ /*
+ * At add_to_page_cache_lru() failure, uncharge will
+ * be done automatically.
+ */
+ if (ret) {
spin_unlock(&info->lock);
- mem_cgroup_uncharge_page(filepage);
page_cache_release(filepage);
shmem_unacct_blocks(info->flags, 1);
shmem_free_blocks(inode, 1);
goto failed;
goto repeat;
}
- mem_cgroup_uncharge_page(filepage);
info->flags |= SHMEM_PAGEIN;
}
projects / linux-2.6 / commitdiff