[PATCH 1/7] res_counter: add a function res_counter_move_parent().

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

This function is used for moving accounting information to its
parent in the hierarchy of res_counter.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
---
 include/linux/res_counter.h |    3 +++
 kernel/res_counter.c        |   13 +++++++++++++
 2 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index da81af0..8919d3c 100644
--- a/include/linux/res_counter.h
+++ b/include/linux/res_counter.h
@@ -135,6 +135,9 @@ int __must_check res_counter_charge_nofail(struct res_counter *counter,
 void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val);
 void res_counter_uncharge(struct res_counter *counter, unsigned long val);
 
+/* move resource to parent counter...i.e. just forget accounting in a child */
+void res_counter_move_parent(struct res_counter *counter, unsigned long val);
+
 /**
  * res_counter_margin - calculate chargeable space of a counter
  * @cnt: the counter
diff --git a/kernel/res_counter.c b/kernel/res_counter.c
index d508363..fafebf0 100644
--- a/kernel/res_counter.c
+++ b/kernel/res_counter.c
@@ -113,6 +113,19 @@ void res_counter_uncharge(struct res_counter *counter, unsigned long val)
 	local_irq_restore(flags);
 }
 
+/*
+ * In hierarchical accounting, child's usage is accounted into ancestors.
+ * To move local usage to its parent, just forget current level usage.
+ */
+void res_counter_move_parent(struct res_counter *counter, unsigned long val)
+{
+	unsigned long flags;
+
+	BUG_ON(!counter->parent);
+	spin_lock_irqsave(&counter->lock, flags);
+	res_counter_uncharge_locked(counter, val);
+	spin_unlock_irqrestore(&counter->lock, flags);
+}
 
 static inline unsigned long long *
 res_counter_member(struct res_counter *counter, int member)
-- 
1.7.4.1


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