Merge pull request #935 from DamianDuy/changeBucketGenerationFor1

[umf] change default MinBucketSize and ensure buckets are generated from the min size 8

Author: pbalcer

source/common/umf_pools/disjoint_pool.cpp

@@ -293,6 +293,8 @@ class DisjointPool::AllocImpl {
         // Generate buckets sized such as: 64, 96, 128, 192, ..., CutOff.
         // Powers of 2 and the value halfway between the powers of 2.
         auto Size1 = params.MinBucketSize;
+        // Buckets sized smaller than the bucket default size- 8 aren't needed.
+        Size1 = std::max(Size1, MIN_BUCKET_DEFAULT_SIZE);
         auto Size2 = Size1 + Size1 / 2;
         for (; Size2 < CutOff; Size1 *= 2, Size2 *= 2) {
             Buckets.push_back(std::make_unique<Bucket>(Size1, *this));

source/common/umf_pools/disjoint_pool.hpp

@@ -17,6 +17,8 @@
 
 namespace usm {
 
+inline constexpr size_t MIN_BUCKET_DEFAULT_SIZE = 8;
+
 // Configuration for specific USM allocator instance
 class DisjointPoolConfig {
   public:
@@ -46,7 +48,7 @@ class DisjointPoolConfig {
 
     // Holds the minimum bucket size valid for allocation of a memory type.
     // This value must be a power of 2.
-    size_t MinBucketSize = 1;
+    size_t MinBucketSize = MIN_BUCKET_DEFAULT_SIZE;
 
     // Holds size of the pool managed by the allocator.
     size_t CurPoolSize = 0;