bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
}
+static int try_lock_page_cgroup(struct page *page)
+{
+ return bit_spin_trylock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
+}
+
static void unlock_page_cgroup(struct page *page)
{
bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
struct mem_cgroup_per_zone *mz;
unsigned long flags;
- pc = page_get_page_cgroup(page);
- if (!pc)
+ /*
+ * We cannot lock_page_cgroup while holding zone's lru_lock,
+ * because other holders of lock_page_cgroup can be interrupted
+ * with an attempt to rotate_reclaimable_page. But we cannot
+ * safely get to page_cgroup without it, so just try_lock it:
+ * mem_cgroup_isolate_pages allows for page left on wrong list.
+ */
+ if (!try_lock_page_cgroup(page))
return;
- mz = page_cgroup_zoneinfo(pc);
- spin_lock_irqsave(&mz->lru_lock, flags);
- __mem_cgroup_move_lists(pc, active);
- spin_unlock_irqrestore(&mz->lru_lock, flags);
+ pc = page_get_page_cgroup(page);
+ if (pc) {
+ mz = page_cgroup_zoneinfo(pc);
+ spin_lock_irqsave(&mz->lru_lock, flags);
+ __mem_cgroup_move_lists(pc, active);
+ spin_unlock_irqrestore(&mz->lru_lock, flags);
+ }
+ unlock_page_cgroup(page);
}
/*
goto retry;
}
page_assign_page_cgroup(page, pc);
- unlock_page_cgroup(page);
mz = page_cgroup_zoneinfo(pc);
spin_lock_irqsave(&mz->lru_lock, flags);
__mem_cgroup_add_list(pc);
spin_unlock_irqrestore(&mz->lru_lock, flags);
+ unlock_page_cgroup(page);
done:
return 0;
out:
VM_BUG_ON(pc->ref_cnt <= 0);
if (--(pc->ref_cnt) == 0) {
- 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(pc);
spin_unlock_irqrestore(&mz->lru_lock, flags);
+ page_assign_page_cgroup(page, NULL);
+ unlock_page_cgroup(page);
+
mem = pc->mem_cgroup;
res_counter_uncharge(&mem->res, PAGE_SIZE);
css_put(&mem->css);
return;
}
- 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(pc);
spin_unlock_irqrestore(&mz->lru_lock, flags);
+ page_assign_page_cgroup(page, NULL);
+ unlock_page_cgroup(page);
+
pc->page = newpage;
lock_page_cgroup(newpage);
page_assign_page_cgroup(newpage, pc);
- unlock_page_cgroup(newpage);
mz = page_cgroup_zoneinfo(pc);
spin_lock_irqsave(&mz->lru_lock, flags);
__mem_cgroup_add_list(pc);
spin_unlock_irqrestore(&mz->lru_lock, flags);
+
+ unlock_page_cgroup(newpage);
}
/*
{
struct page_cgroup *pc;
struct page *page;
- int count;
+ int count = FORCE_UNCHARGE_BATCH;
unsigned long flags;
struct list_head *list;
else
list = &mz->inactive_list;
- if (list_empty(list))
- return;
-retry:
- count = FORCE_UNCHARGE_BATCH;
spin_lock_irqsave(&mz->lru_lock, flags);
-
- while (--count && !list_empty(list)) {
+ while (!list_empty(list)) {
pc = list_entry(list->prev, struct page_cgroup, lru);
page = pc->page;
- lock_page_cgroup(page);
- if (page_get_page_cgroup(page) == pc) {
- page_assign_page_cgroup(page, NULL);
- unlock_page_cgroup(page);
- __mem_cgroup_remove_list(pc);
- res_counter_uncharge(&mem->res, PAGE_SIZE);
- css_put(&mem->css);
- kfree(pc);
- } else {
- /* racing uncharge: let page go then retry */
- unlock_page_cgroup(page);
- break;
+ get_page(page);
+ spin_unlock_irqrestore(&mz->lru_lock, flags);
+ mem_cgroup_uncharge_page(page);
+ put_page(page);
+ if (--count <= 0) {
+ count = FORCE_UNCHARGE_BATCH;
+ cond_resched();
}
+ spin_lock_irqsave(&mz->lru_lock, flags);
}
-
spin_unlock_irqrestore(&mz->lru_lock, flags);
- if (!list_empty(list)) {
- cond_resched();
- goto retry;
- }
}
/*