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

src/util.cpp

@@ -72,6 +72,10 @@
 #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()
@@ -792,6 +796,16 @@ void RenameThread(const char* name)
 
 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__)