res_counter: update documentation
After the introduction of resource counters hierarchies
(28dbc4b6a01fb579a9441c7b81e3d3413dc452df) the prototypes of
res_counter_init() and res_counter_charge() have been changed.
Keep the documentation consistent with the actual function prototypes.
Signed-off-by: Andrea Righi <righi.andrea@gmail.com>
Cc: Paul Menage <menage@google.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/cgroups/resource_counter.txt b/Documentation/cgroups/resource_counter.txt
index f196ac1..95b24d7 100644
--- a/Documentation/cgroups/resource_counter.txt
+++ b/Documentation/cgroups/resource_counter.txt
@@ -47,13 +47,18 @@
2. Basic accounting routines
- a. void res_counter_init(struct res_counter *rc)
+ a. void res_counter_init(struct res_counter *rc,
+ struct res_counter *rc_parent)
Initializes the resource counter. As usual, should be the first
routine called for a new counter.
- b. int res_counter_charge[_locked]
- (struct res_counter *rc, unsigned long val)
+ The struct res_counter *parent can be used to define a hierarchical
+ child -> parent relationship directly in the res_counter structure,
+ NULL can be used to define no relationship.
+
+ c. int res_counter_charge(struct res_counter *rc, unsigned long val,
+ struct res_counter **limit_fail_at)
When a resource is about to be allocated it has to be accounted
with the appropriate resource counter (controller should determine
@@ -67,15 +72,25 @@
* if the charging is performed first, then it should be uncharged
on error path (if the one is called).
- c. void res_counter_uncharge[_locked]
+ If the charging fails and a hierarchical dependency exists, the
+ limit_fail_at parameter is set to the particular res_counter element
+ where the charging failed.
+
+ d. int res_counter_charge_locked
+ (struct res_counter *rc, unsigned long val)
+
+ The same as res_counter_charge(), but it must not acquire/release the
+ res_counter->lock internally (it must be called with res_counter->lock
+ held).
+
+ e. void res_counter_uncharge[_locked]
(struct res_counter *rc, unsigned long val)
When a resource is released (freed) it should be de-accounted
from the resource counter it was accounted to. This is called
"uncharging".
- The _locked routines imply that the res_counter->lock is taken.
-
+ The _locked routines imply that the res_counter->lock is taken.
2.1 Other accounting routines