From 42d3060568945271f36af6fa6ec7c25dfeae9708 Mon Sep 17 00:00:00 2001
From: "Wladimir J. van der Laan" <laanwj@gmail.com>
Date: Fri, 31 Mar 2017 10:36:18 +0200
Subject: [PATCH] Merge #10120: util: Work around (virtual) memory exhaustion
 on 32-bit w/ glibc

625488a util: Work around (virtual) memory exhaustion on 32-bit w/ glibc (Wladimir J. van der Laan)

Tree-SHA512: 99b610a8cf9561998af90e16fc19320fddd30c987e8f33325d63df0f56d70235b94d9482e80f28154d4b33a3ecf4961686380c444ec18d1da5e8804a8b6f4de1
---
 configure.ac |  8 ++++++++
 src/util.cpp | 14 ++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/configure.ac b/configure.ac
index 57acbb5d7b..29f271b11c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -558,6 +558,14 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/socket.h>]],
  [ AC_MSG_RESULT(no)]
 )
 
+dnl Check for mallopt(M_ARENA_MAX) (to set glibc arenas)
+AC_MSG_CHECKING(for mallopt M_ARENA_MAX)
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <malloc.h>]],
+ [[ mallopt(M_ARENA_MAX, 1); ]])],
+ [ AC_MSG_RESULT(yes); AC_DEFINE(HAVE_MALLOPT_ARENA_MAX, 1,[Define this symbol if you have mallopt with M_ARENA_MAX]) ],
+ [ AC_MSG_RESULT(no)]
+)
+
 AC_MSG_CHECKING([for visibility attribute])
 AC_LINK_IFELSE([AC_LANG_SOURCE([
   int foo_def( void ) __attribute__((visibility("default")));
diff --git a/src/util.cpp b/src/util.cpp
index 838fa41dd8..18391c53a1 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -75,6 +75,10 @@
 #include <sys/prctl.h>
 #endif
 
+#ifdef HAVE_MALLOPT_ARENA_MAX
+#include <malloc.h>
+#endif
+
 #include <boost/algorithm/string/case_conv.hpp> // for to_lower()
 #include <boost/algorithm/string/join.hpp>
 #include <boost/algorithm/string/predicate.hpp> // for startswith() and endswith()
@@ -903,6 +907,16 @@ std::string GetThreadName()
 
 void SetupEnvironment()
 {
+#ifdef HAVE_MALLOPT_ARENA_MAX
+    // glibc-specific: On 32-bit systems set the number of arenas to 1.
+    // By default, since glibc 2.10, the C library will create up to two heap
+    // arenas per core. This is known to cause excessive virtual address space
+    // usage in our usage. Work around it by setting the maximum number of
+    // arenas to 1.
+    if (sizeof(void*) == 4) {
+        mallopt(M_ARENA_MAX, 1);
+    }
+#endif
     // On most POSIX systems (e.g. Linux, but not BSD) the environment's locale
     // may be invalid, in which case the "C" locale is used as fallback.
 #if !defined(WIN32) && !defined(MAC_OSX) && !defined(__FreeBSD__) && !defined(__OpenBSD__)