diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_persistent_allocator.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_persistent_allocator.cpp
index 1ca0375b8a54..04d4c2829a54 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_persistent_allocator.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_persistent_allocator.cpp
@@ -15,4 +15,21 @@ namespace __sanitizer {
 
 PersistentAllocator thePersistentAllocator;
 
+void *PersistentAllocator::refillAndAlloc(uptr size) {
+  // If failed, lock, retry and alloc new superblock.
+  SpinMutexLock l(&mtx);
+  for (;;) {
+    void *s = tryAlloc(size);
+    if (s)
+      return s;
+    atomic_store(&region_pos, 0, memory_order_relaxed);
+    uptr allocsz = 64 * 1024;
+    if (allocsz < size)
+      allocsz = size;
+    uptr mem = (uptr)MmapOrDie(allocsz, "stack depot");
+    atomic_store(&region_end, mem + allocsz, memory_order_release);
+    atomic_store(&region_pos, mem, memory_order_release);
+  }
+}
+
 }  // namespace __sanitizer
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_persistent_allocator.h b/compiler-rt/lib/sanitizer_common/sanitizer_persistent_allocator.h
index de4fb6ebc3cf..ae3a023d0786 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_persistent_allocator.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_persistent_allocator.h
@@ -26,6 +26,7 @@ class PersistentAllocator {
 
  private:
   void *tryAlloc(uptr size);
+  void *refillAndAlloc(uptr size);
   StaticSpinMutex mtx;  // Protects alloc of new blocks for region allocator.
   atomic_uintptr_t region_pos;  // Region allocator for Node's.
   atomic_uintptr_t region_end;
@@ -47,18 +48,7 @@ inline void *PersistentAllocator::alloc(uptr size) {
   // First, try to allocate optimisitically.
   void *s = tryAlloc(size);
   if (s) return s;
-  // If failed, lock, retry and alloc new superblock.
-  SpinMutexLock l(&mtx);
-  for (;;) {
-    s = tryAlloc(size);
-    if (s) return s;
-    atomic_store(&region_pos, 0, memory_order_relaxed);
-    uptr allocsz = 64 * 1024;
-    if (allocsz < size) allocsz = size;
-    uptr mem = (uptr)MmapOrDie(allocsz, "stack depot");
-    atomic_store(&region_end, mem + allocsz, memory_order_release);
-    atomic_store(&region_pos, mem, memory_order_release);
-  }
+  return refillAndAlloc(size);
 }
 
 extern PersistentAllocator thePersistentAllocator;