1 files changed, 77 insertions, 0 deletions
diff --git a/src/rocksdb/port/jemalloc_helper.h b/src/rocksdb/port/jemalloc_helper.h
new file mode 100644
index 000000000..f6f72f8cb
--- /dev/null
+++ b/src/rocksdb/port/jemalloc_helper.h
@@ -0,0 +1,77 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#pragma once
+
+#if defined(__clang__)
+// glibc's `posix_memalign()` declaration specifies `throw()` while clang's
+// declaration does not. There is a hack in clang to make its re-declaration
+// compatible with glibc's if they are declared consecutively. That hack breaks
+// if yet another `posix_memalign()` declaration comes between glibc's and
+// clang's declarations. Include "mm_malloc.h" here ensures glibc's and clang's
+// declarations both come before "jemalloc.h"'s `posix_memalign()` declaration.
+//
+// This problem could also be avoided if "jemalloc.h"'s `posix_memalign()`
+// declaration did not specify `throw()` when built with clang.
+#include <mm_malloc.h>
+#endif
+
+#ifdef ROCKSDB_JEMALLOC
+#ifdef __FreeBSD__
+#include <malloc_np.h>
+#else
+#define JEMALLOC_MANGLE
+#include <jemalloc/jemalloc.h>
+#endif
+
+#ifndef JEMALLOC_CXX_THROW
+#define JEMALLOC_CXX_THROW
+#endif
+
+#if defined(OS_WIN) && defined(_MSC_VER)
+
+// MSVC does not have weak symbol support. As long as ROCKSDB_JEMALLOC is
+// defined, Jemalloc memory allocator is used.
+static inline bool HasJemalloc() { return true; }
+
+#else
+
+// Declare non-standard jemalloc APIs as weak symbols. We can null-check these
+// symbols to detect whether jemalloc is linked with the binary.
+extern "C" void* mallocx(size_t, int) __attribute__((__weak__));
+extern "C" void* rallocx(void*, size_t, int) __attribute__((__weak__));
+extern "C" size_t xallocx(void*, size_t, size_t, int) __attribute__((__weak__));
+extern "C" size_t sallocx(const void*, int) __attribute__((__weak__));
+extern "C" void dallocx(void*, int) __attribute__((__weak__));
+extern "C" void sdallocx(void*, size_t, int) __attribute__((__weak__));
+extern "C" size_t nallocx(size_t, int) __attribute__((__weak__));
+extern "C" int mallctl(const char*, void*, size_t*, void*, size_t)
+    __attribute__((__weak__));
+extern "C" int mallctlnametomib(const char*, size_t*, size_t*)
+    __attribute__((__weak__));
+extern "C" int mallctlbymib(const size_t*, size_t, void*, size_t*, void*,
+                            size_t) __attribute__((__weak__));
+extern "C" void malloc_stats_print(void (*)(void*, const char*), void*,
+                                   const char*) __attribute__((__weak__));
+extern "C" size_t malloc_usable_size(JEMALLOC_USABLE_SIZE_CONST void*)
+    JEMALLOC_CXX_THROW __attribute__((__weak__));
+
+// Check if Jemalloc is linked with the binary. Note the main program might be
+// using a different memory allocator even this method return true.
+// It is loosely based on folly::usingJEMalloc(), minus the check that actually
+// allocate memory and see if it is through jemalloc, to handle the dlopen()
+// case:
+// https://github.com/facebook/folly/blob/76cf8b5841fb33137cfbf8b224f0226437c855bc/folly/memory/Malloc.h#L147
+static inline bool HasJemalloc() {
+  return mallocx != nullptr && rallocx != nullptr && xallocx != nullptr &&
+         sallocx != nullptr && dallocx != nullptr && sdallocx != nullptr &&
+         nallocx != nullptr && mallctl != nullptr &&
+         mallctlnametomib != nullptr && mallctlbymib != nullptr &&
+         malloc_stats_print != nullptr && malloc_usable_size != nullptr;
+}
+
+#endif
+
+#endif  // ROCKSDB_JEMALLOC