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>

1 files changed, 21 insertions, 6 deletions

diff --git a/Documentation/cgroups/resource_counter.txt b/Documentation/cgroups/resource_counter.txt
index f196ac1d7d25..95b24d766eab 100644
--- a/Documentation/cgroups/resource_counter.txt
+++ b/Documentation/cgroups/resource_counter.txt
@@ -47,13 +47,18 @@ to work with it.
 
 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 @@ to work with it.
           * 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