[ur] Refactor ur_usm_pool_limits_desc_t

Remove capacity field - having a single limit for all buckets does not
make much sense. It's also hard to pick a correct value without any
runtime allocation statistics.

Rename maxPoolSize to maxUnfreedMemory to make it more clear.

Author: igchor

include/ur.py

@@ -905,8 +905,8 @@ class ur_usm_pool_limits_desc_t(Structure):
         ("pNext", c_void_p),                                            ## [in][optional] pointer to extension-specific structure
         ("maxPoolSize", c_size_t),                                      ## [in] Maximum size of a memory pool
         ("maxPoolableSize", c_size_t),                                  ## [in] Allocations up to this limit will be subject to pooling
-        ("capacity", c_size_t),                                         ## [in] When pooling, each bucket will hold a max of 4 unfreed slabs
-        ("slabMinSize", c_size_t)                                       ## [in] Minimum allocation size that will be requested from the driver
+        ("bucketCapacity", c_size_t),                                   ## [in] Maximum number of unfreed allocations in each bucket
+        ("minDriverAllocSize", c_size_t)                                ## [in] Minimum allocation size that will be requested from the driver
     ]
 
 ###############################################################################

include/ur_api.h

@@ -2083,8 +2083,8 @@ typedef struct ur_usm_pool_limits_desc_t {
     const void *pNext;         ///< [in][optional] pointer to extension-specific structure
     size_t maxPoolSize;        ///< [in] Maximum size of a memory pool
     size_t maxPoolableSize;    ///< [in] Allocations up to this limit will be subject to pooling
-    size_t capacity;           ///< [in] When pooling, each bucket will hold a max of 4 unfreed slabs
-    size_t slabMinSize;        ///< [in] Minimum allocation size that will be requested from the driver
+    size_t bucketCapacity;     ///< [in] Maximum number of unfreed allocations in each bucket
+    size_t minDriverAllocSize; ///< [in] Minimum allocation size that will be requested from the driver
 
 } ur_usm_pool_limits_desc_t;
 

scripts/core/usm.yml

@@ -130,16 +130,13 @@ name: $x_usm_pool_limits_desc_t
 base: $x_base_desc_t
 members:
     - type: "size_t"
-      name:  maxPoolSize
-      desc: "[in] Maximum size of a memory pool"
+      name:  maxUnfreedMemory
+      desc: "[in] Maximum amount of free memory kept in the pool"
     - type: "size_t"
       name:  maxPoolableSize
       desc: "[in] Allocations up to this limit will be subject to pooling"
     - type: "size_t"
-      name:  capacity
-      desc: "[in] When pooling, each bucket will hold a max of 4 unfreed slabs"
-    - type: "size_t"
-      name:  slabMinSize
+      name:  minDriverAllocSize
       desc: "[in] Minimum allocation size that will be requested from the driver"
 --- #--------------------------------------------------------------------------
 type: function