Avoid crossing the creek multiple times to get an empty bucket of water.

2 files changed, 14 insertions, 2 deletions

diff --git a/vespalib/src/vespa/vespalib/util/alloc.cpp b/vespalib/src/vespa/vespalib/util/alloc.cpp
index dff744a0a41..e4fb44bc618 100644
--- a/vespalib/src/vespa/vespalib/util/alloc.cpp
+++ b/vespalib/src/vespa/vespalib/util/alloc.cpp
@@ -213,6 +213,7 @@ alloc::AlignedHeapAllocator _G_4KalignedHeapAllocator(1024);
 alloc::AlignedHeapAllocator _G_1KalignedHeapAllocator(4096);
 alloc::AlignedHeapAllocator _G_512BalignedHeapAllocator(512);
 alloc::MMapAllocator _G_mmapAllocatorDefault;
+alloc::MemoryAllocator *_G_defaultAutAllocator = nullptr;
 
 }
 
@@ -466,6 +467,15 @@ Alloc::allocMMap(size_t sz)
 }
 
 Alloc
+Alloc::alloc()
+{
+    if (_G_defaultAutAllocator == nullptr) {
+        _G_defaultAutAllocator = &AutoAllocator::getDefault();
+    }
+    return Alloc(_G_defaultAutAllocator);
+}
+
+Alloc
 Alloc::alloc(size_t sz, size_t mmapLimit, size_t alignment)
 {
     return Alloc(&AutoAllocator::getAllocator(mmapLimit, alignment), sz);
diff --git a/vespalib/src/vespa/vespalib/util/alloc.h b/vespalib/src/vespa/vespalib/util/alloc.h
index 2c3de92c58e..b52cace45a5 100644
--- a/vespalib/src/vespa/vespalib/util/alloc.h
+++ b/vespalib/src/vespa/vespalib/util/alloc.h
@@ -88,7 +88,7 @@ public:
         std::swap(_allocator, rhs._allocator);
     }
     Alloc create(size_t sz) const {
-        return Alloc(_allocator, sz);
+        return (sz == 0) ? Alloc(_allocator) : Alloc(_allocator, sz);
     }
 
     static Alloc allocAlignedHeap(size_t sz, size_t alignment);
@@ -98,9 +98,11 @@ public:
      * Optional alignment is assumed to be <= system page size, since mmap
      * is always used when size is above limit.
      */
-    static Alloc alloc(size_t sz=0, size_t mmapLimit = MemoryAllocator::HUGEPAGE_SIZE, size_t alignment=0);
+    static Alloc alloc(size_t sz, size_t mmapLimit = MemoryAllocator::HUGEPAGE_SIZE, size_t alignment=0);
+    static Alloc alloc();
 private:
     Alloc(const MemoryAllocator * allocator, size_t sz) : _alloc(allocator->alloc(sz)), _allocator(allocator) { }
+    Alloc(const MemoryAllocator * allocator) : _alloc(nullptr, 0), _allocator(allocator) { }
     void clear() {
         _alloc.first = nullptr;
         _alloc.second = 0;