Addressing CR feedback

2019-01-16 17:03:15 +00:00
parent c4e6af4bad
commit ab57c86e3a
2 changed files with 22 additions and 10 deletions
--- a/src/mem/alloc.h
+++ b/src/mem/alloc.h
@@ -38,10 +38,17 @@ namespace snmalloc
    PMMediumslab = 2
  };

+#ifndef SNMALLOC_MAX_FLATPAGEMAP_SIZE
+// Use flat map is under a single node.
+#  define SNMALLOC_MAX_FLATPAGEMAP_SIZE PAGEMAP_NODE_SIZE
+#endif
+  static constexpr bool USE_FLATPAGEMAP = SNMALLOC_MAX_FLATPAGEMAP_SIZE >=
+    sizeof(FlatPagemap<SUPERSLAB_BITS, uint8_t>);
+
  using SuperslabPagemap = std::conditional_t<
-    bits::is64(),
-    Pagemap<SUPERSLAB_BITS, uint8_t, 0>,
-    FlatPagemap<SUPERSLAB_BITS, uint8_t>>;
+    USE_FLATPAGEMAP,
+    FlatPagemap<SUPERSLAB_BITS, uint8_t>,
+    Pagemap<SUPERSLAB_BITS, uint8_t, 0>>;

  HEADER_GLOBAL SuperslabPagemap global_pagemap;
  /**