It is one logical function, no need to have it split up.
Also, get rid of some checks from the inner function that ensured the
sanity of the outer function.
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
include/linux/page_cgroup.h | 5 ---
mm/memcontrol.c | 66 +++++++++++++++++++------------------------
2 files changed, 29 insertions(+), 42 deletions(-)
diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
index 363bbc8..6b63679 100644
--- a/include/linux/page_cgroup.h
+++ b/include/linux/page_cgroup.h
@@ -99,11 +99,6 @@ static inline void unlock_page_cgroup(struct page_cgroup *pc)
bit_spin_unlock(PCG_LOCK, &pc->flags);
}
-static inline int page_is_cgroup_locked(struct page_cgroup *pc)
-{
- return bit_spin_is_locked(PCG_LOCK, &pc->flags);
-}
-
static inline void move_lock_page_cgroup(struct page_cgroup *pc,
unsigned long *flags)
{
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 77a3f87..5eb0dc2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2174,33 +2174,49 @@ void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
#endif
/**
- * __mem_cgroup_move_account - move account of the page
+ * mem_cgroup_move_account - move account of the page
* @pc: page_cgroup of the page.
* @from: mem_cgroup which the page is moved from.
* @to: mem_cgroup which the page is moved to. @from != @to.
* @uncharge: whether we should call uncharge and css_put against @from.
+ * @charge_size: number of bytes to charge (regular or huge page)
*
* The caller must confirm following.
* - page is not on LRU (isolate_page() is useful.)
- * - the pc is locked, used, and ->mem_cgroup points to @from.
+ * - compound_lock is held when charge_size > PAGE_SIZE
*
* This function doesn't do "charge" nor css_get to new cgroup. It should be
* done by a caller(__mem_cgroup_try_charge would be usefull). If @uncharge is
* true, this function does "uncharge" from old cgroup, but it doesn't if
* @uncharge is false, so a caller should do "uncharge".
*/
-
-static void __mem_cgroup_move_account(struct page_cgroup *pc,
- struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge,
- int charge_size)
+static int mem_cgroup_move_account(struct page_cgroup *pc,
+ struct mem_cgroup *from, struct mem_cgroup *to,
+ bool uncharge, int charge_size)
{
int nr_pages = charge_size >> PAGE_SHIFT;
+ unsigned long flags;
+ int ret;
VM_BUG_ON(from == to);
VM_BUG_ON(PageLRU(pc->page));
- VM_BUG_ON(!page_is_cgroup_locked(pc));
- VM_BUG_ON(!PageCgroupUsed(pc));
- VM_BUG_ON(pc->mem_cgroup != from);
+ /*
+ * The page is isolated from LRU. So, collapse function
+ * will not handle this page. But page splitting can happen.
+ * Do this check under compound_page_lock(). The caller should
+ * hold it.
+ */
+ ret = -EBUSY;
+ if (charge_size > PAGE_SIZE && !PageTransHuge(pc->page))
+ goto out;
+
+ lock_page_cgroup(pc);
+
+ ret = -EINVAL;
+ if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
+ goto unlock;
+
+ move_lock_page_cgroup(pc, &flags);
if (PageCgroupFileMapped(pc)) {
/* Update mapped_file data for mem_cgroup */
@@ -2224,40 +2240,16 @@ static void __mem_cgroup_move_account(struct page_cgroup *pc,
* garanteed that "to" is never removed. So, we don't check rmdir
* status here.
*/
-}
-
-/*
- * check whether the @pc is valid for moving account and call
- * __mem_cgroup_move_account()
- */
-static int mem_cgroup_move_account(struct page_cgroup *pc,
- struct mem_cgroup *from, struct mem_cgroup *to,
- bool uncharge, int charge_size)
-{
- int ret = -EINVAL;
- unsigned long flags;
- /*
- * The page is isolated from LRU. So, collapse function
- * will not handle this page. But page splitting can happen.
- * Do this check under compound_page_lock(). The caller should
- * hold it.
- */
- if ((charge_size > PAGE_SIZE) && !PageTransHuge(pc->page))
- return -EBUSY;
-
- lock_page_cgroup(pc);
- if (PageCgroupUsed(pc) && pc->mem_cgroup == from) {
- move_lock_page_cgroup(pc, &flags);
- __mem_cgroup_move_account(pc, from, to, uncharge, charge_size);
- move_unlock_page_cgroup(pc, &flags);
- ret = 0;
- }
+ move_unlock_page_cgroup(pc, &flags);
+ ret = 0;
+unlock:
unlock_page_cgroup(pc);
/*
* check events
*/
memcg_check_events(to, pc->page);
memcg_check_events(from, pc->page);
+out:
return ret;
}
--
1.7.4
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