Add the --enable-mremap option.
Add the --enable-mremap option, and disable the use of mremap(2) by
default, for the same reason that freeing chunks via munmap(2) is
disabled by default on Linux: semi-permanent VM map fragmentation.
diff --git a/configure.ac b/configure.ac
index 3b32b88..a09db7d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -372,16 +372,6 @@
AC_DEFINE([JEMALLOC_TLS_MODEL], [ ])
fi
-JE_COMPILABLE([mremap(...MREMAP_FIXED...)], [
-#define _GNU_SOURCE
-#include <sys/mman.h>
-], [
-void *p = mremap((void *)0, 0, 0, MREMAP_MAYMOVE|MREMAP_FIXED, (void *)0);
-], [je_cv_mremap_fixed])
-if test "x${je_cv_mremap_fixed}" = "xyes" ; then
- AC_DEFINE([JEMALLOC_MREMAP_FIXED], [ ])
-fi
-
dnl Support optional additions to rpath.
AC_ARG_WITH([rpath],
[AS_HELP_STRING([--with-rpath=<rpath>], [Colon-separated rpath (ELF systems only)])],
@@ -743,6 +733,33 @@
fi
AC_SUBST([enable_tcache])
+dnl Disable mremap() for huge realloc() by default.
+AC_ARG_ENABLE([mremap],
+ [AS_HELP_STRING([--enable-mremap], [Enable mremap(2) for huge realloc()])],
+[if test "x$enable_mremap" = "xno" ; then
+ enable_mremap="0"
+else
+ enable_mremap="1"
+fi
+],
+[enable_mremap="0"]
+)
+if test "x$enable_mremap" = "x1" ; then
+ JE_COMPILABLE([mremap(...MREMAP_FIXED...)], [
+#define _GNU_SOURCE
+#include <sys/mman.h>
+], [
+void *p = mremap((void *)0, 0, 0, MREMAP_MAYMOVE|MREMAP_FIXED, (void *)0);
+], [je_cv_mremap_fixed])
+ if test "x${je_cv_mremap_fixed}" = "xno" ; then
+ enable_mremap="0"
+ fi
+fi
+if test "x$enable_mremap" = "x1" ; then
+ AC_DEFINE([JEMALLOC_MREMAP], [ ])
+fi
+AC_SUBST([enable_mremap])
+
dnl Enable VM deallocation via munmap() by default.
AC_ARG_ENABLE([munmap],
[AS_HELP_STRING([--disable-munmap], [Disable VM deallocation via munmap(2)])],
@@ -1261,6 +1278,7 @@
AC_MSG_RESULT([utrace : ${enable_utrace}])
AC_MSG_RESULT([valgrind : ${enable_valgrind}])
AC_MSG_RESULT([xmalloc : ${enable_xmalloc}])
+AC_MSG_RESULT([mremap : ${enable_mremap}])
AC_MSG_RESULT([munmap : ${enable_munmap}])
AC_MSG_RESULT([dss : ${enable_dss}])
AC_MSG_RESULT([lazy_lock : ${enable_lazy_lock}])