lib: objagg: implement optimization hints assembly and use hints for object creation

Implement simple greedy algo to find more optimized root-delta tree for
a given objagg instance. This "hints" can be used by a driver to:
1) check if the hints are better (driver's choice) than the original
   objagg tree. Driver does comparison of objagg stats and hints stats.
2) use the hints to create a new objagg instance which will construct
   the root-delta tree according to the passed hints. Currently, only a
   simple greedy algorithm is implemented. Basically it finds the roots
   according to the maximal possible user count including deltas.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 2 deletions

diff --git a/include/linux/objagg.h b/include/linux/objagg.h
index 34f38c186ea0..a675286df1af 100644
--- a/include/linux/objagg.h
+++ b/include/linux/objagg.h
@@ -6,14 +6,19 @@
 
 struct objagg_ops {
         size_t obj_size;
+        bool (*delta_check)(void *priv, const void *parent_obj,
+                            const void *obj);
+        int (*hints_obj_cmp)(const void *obj1, const void *obj2);
         void * (*delta_create)(void *priv, void *parent_obj, void *obj);
         void (*delta_destroy)(void *priv, void *delta_priv);
-        void * (*root_create)(void *priv, void *obj);
+        void * (*root_create)(void *priv, void *obj, unsigned int root_id);
+#define OBJAGG_OBJ_ROOT_ID_INVALID UINT_MAX
         void (*root_destroy)(void *priv, void *root_priv);
 };
 
 struct objagg;
 struct objagg_obj;
+struct objagg_hints;
 
 const void *objagg_obj_root_priv(const struct objagg_obj *objagg_obj);
 const void *objagg_obj_delta_priv(const struct objagg_obj *objagg_obj);
@@ -21,7 +26,8 @@ const void *objagg_obj_raw(const struct objagg_obj *objagg_obj);
 
 struct objagg_obj *objagg_obj_get(struct objagg *objagg, void *obj);
 void objagg_obj_put(struct objagg *objagg, struct objagg_obj *objagg_obj);
-struct objagg *objagg_create(const struct objagg_ops *ops, void *priv);
+struct objagg *objagg_create(const struct objagg_ops *ops,
+                             struct objagg_hints *hints, void *priv);
 void objagg_destroy(struct objagg *objagg);
 
 struct objagg_obj_stats {
@@ -43,4 +49,14 @@ struct objagg_stats {
 const struct objagg_stats *objagg_stats_get(struct objagg *objagg);
 void objagg_stats_put(const struct objagg_stats *objagg_stats);
 
+enum objagg_opt_algo_type {
+        OBJAGG_OPT_ALGO_SIMPLE_GREEDY,
+};
+
+struct objagg_hints *objagg_hints_get(struct objagg *objagg,
+                                      enum objagg_opt_algo_type opt_algo_type);
+void objagg_hints_put(struct objagg_hints *objagg_hints);
+const struct objagg_stats *
+objagg_hints_stats_get(struct objagg_hints *objagg_hints);
+
 #endif