[commit: ghc] master: configure.ac: Allow disabling of large-address-space (fba724c)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/fba724ccabd295fc37e71ba6c4f892822a831d19/ghc

>---------------------------------------------------------------

commit fba724ccabd295fc37e71ba6c4f892822a831d19
Author: Erik de Castro Lopo <erikd at mega-nerd.com>
Date:   Tue Aug 25 11:33:32 2015 +1000

    configure.ac: Allow disabling of large-address-space
    
    Recent changes (commit 0d1a8d09f4) for 64 bit platforms allowed GHC
    to mmap one huge (currently 1 terrabyte) memory region from which to
    do its own allocations. This is enabled by default, but it would be
    nice (even just from the point of view of testing) to be able to
    disable this at configure time.
    
    Test Plan: configure and grep mk/config.h for USE_LARGE_ADDRESS_SPACE
    
    Reviewers: austin, ezyang, bgamari, rwbarton
    
    Subscribers: thomie
    
    Differential Revision: https://phabricator.haskell.org/D1170
    
    GHC Trac Issues: #10791


>---------------------------------------------------------------

fba724ccabd295fc37e71ba6c4f892822a831d19
 configure.ac | 42 ++++++++++++++++++++++++++----------------
 1 file changed, 26 insertions(+), 16 deletions(-)

diff --git a/configure.ac b/configure.ac
index e7f9144..793ec0f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1066,24 +1066,34 @@ dnl runs out of paging file when we have multiple processes reserving
 dnl 1TB of address space, we get the following error:
 dnl    VirtualAlloc MEM_RESERVE 1099512676352 bytes failed: The paging file is too small for this operation to complete.
 dnl
+
+AC_ARG_ENABLE(large-address-space,
+    [AC_HELP_STRING([--enable-large-address-space],
+        [Use a single large address space on 64 bit systems (enabled by default on 64 bit platforms)])],
+    EnableLargeAddressSpace=$enableval,
+    EnableLargeAddressSpace=yes
+)
+
 use_large_address_space=no
 if test "$ac_cv_sizeof_void_p" -eq 8 ; then
-   if test "$ghc_host_os" = "darwin" ; then
-           use_large_address_space=yes
-   else
-      AC_CHECK_DECLS([MAP_NORESERVE, MADV_FREE, MADV_DONTNEED],[],[],
-[
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/mman.h>
-#include <fcntl.h>
-])
-      if test "$ac_cv_have_decl_MAP_NORESERVE" = "yes" &&
-         test "$ac_cv_have_decl_MADV_FREE" = "yes" ||
-         test "$ac_cv_have_decl_MADV_DONTNEED" = "yes" ; then
-              use_large_address_space=yes
-      fi
-   fi
+    if test "x$EnableLargeAddressSpace" = "xyes" ; then
+        if test "$ghc_host_os" = "darwin" ; then
+            use_large_address_space=yes
+        else
+            AC_CHECK_DECLS([MAP_NORESERVE, MADV_FREE, MADV_DONTNEED],[],[],
+                [
+                #include <unistd.h>
+                #include <sys/types.h>
+                #include <sys/mman.h>
+                #include <fcntl.h>
+            ])
+            if test "$ac_cv_have_decl_MAP_NORESERVE" = "yes" &&
+                test "$ac_cv_have_decl_MADV_FREE" = "yes" ||
+                test "$ac_cv_have_decl_MADV_DONTNEED" = "yes" ; then
+                    use_large_address_space=yes
+            fi
+        fi
+    fi
 fi
 if test "$use_large_address_space" = "yes" ; then
    AC_DEFINE([USE_LARGE_ADDRESS_SPACE], [1], [Enable single heap address space support])