diff --git a/libc/private/bionic_allocator.h b/libc/private/bionic_allocator.h
new file mode 100644
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--- /dev/null
+++ b/libc/private/bionic_allocator.h
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <errno.h>
+#include <stdlib.h>
+#include <sys/cdefs.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+#include <stddef.h>
+#include <unistd.h>
+
+const uint32_t kSmallObjectMaxSizeLog2 = 10;
+const uint32_t kSmallObjectMinSizeLog2 = 4;
+const uint32_t kSmallObjectAllocatorsCount = kSmallObjectMaxSizeLog2 - kSmallObjectMinSizeLog2 + 1;
+
+class BionicSmallObjectAllocator;
+
+// This structure is placed at the beginning of each addressable page
+// and has all information we need to find the corresponding memory allocator.
+struct page_info {
+  char signature[4];
+  uint32_t type;
+  union {
+    // we use allocated_size for large objects allocator
+    size_t allocated_size;
+    // and allocator_addr for small ones.
+    BionicSmallObjectAllocator* allocator_addr;
+  };
+};
+
+struct small_object_block_record {
+  small_object_block_record* next;
+  size_t free_blocks_cnt;
+};
+
+// This structure is placed at the beginning of each page managed by
+// BionicSmallObjectAllocator.  Note that a page_info struct is expected at the
+// beginning of each page as well, and therefore this structure contains a
+// page_info as its *first* field.
+struct small_object_page_info {
+  page_info info;  // Must be the first field.
+
+  // Doubly linked list for traversing all pages allocated by a
+  // BionicSmallObjectAllocator.
+  small_object_page_info* next_page;
+  small_object_page_info* prev_page;
+
+  // Linked list containing all free blocks in this page.
+  small_object_block_record* free_block_list;
+
+  // Free blocks counter.
+  size_t free_blocks_cnt;
+};
+
+class BionicSmallObjectAllocator {
+ public:
+  BionicSmallObjectAllocator(uint32_t type, size_t block_size);
+  void* alloc();
+  void free(void* ptr);
+
+  size_t get_block_size() const { return block_size_; }
+ private:
+  void alloc_page();
+  void free_page(small_object_page_info* page);
+  void add_to_page_list(small_object_page_info* page);
+  void remove_from_page_list(small_object_page_info* page);
+
+  const uint32_t type_;
+  const size_t block_size_;
+  const size_t blocks_per_page_;
+
+  size_t free_pages_cnt_;
+
+  small_object_page_info* page_list_;
+};
+
+class BionicAllocator {
+ public:
+  constexpr BionicAllocator() : allocators_(nullptr), allocators_buf_() {}
+  void* alloc(size_t size);
+
+  // Note that this implementation of realloc never shrinks allocation
+  void* realloc(void* ptr, size_t size);
+  void free(void* ptr);
+ private:
+  void* alloc_mmap(size_t size);
+  page_info* get_page_info(void* ptr);
+  BionicSmallObjectAllocator* get_small_object_allocator(uint32_t type);
+  void initialize_allocators();
+
+  BionicSmallObjectAllocator* allocators_;
+  uint8_t allocators_buf_[sizeof(BionicSmallObjectAllocator)*kSmallObjectAllocatorsCount];
+};