Hey guys,
Recent changes to malloc on OpenBSD mean that nhc98 builds now die with
the "OS allocated a heap in high memory" error, as malloc is putting
things above the 0x80000000 line.
Switching the heap allocation to use mmap with a hint to allocate
somewhere lower fixes it at least on x86/openbsd. The ghc testsuite
runs, for example. The mmap code is stolen from MBlock.c in ghc.
Any options on this? Is it reasonable? (I'd like to use it as a custom
patch in the OpenBSD port of nhc98, but want to check I'm not doing
anything hideously wrong :)
-- Don
Here's what I'm doing:
--- src/runtime/Kernel/collector.c.orig Tue Mar 8 03:53:38 2005
+++ src/runtime/Kernel/collector.c Sat Oct 22 19:05:22 2005
@@ -7,6 +7,11 @@
/*#include "runtime.h" -- already included in node.h */
#include "mark.h"
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+
+
/*#define HEAPSIZE 100000 -- defined in top-level Makefile at config-time */
#define GCSTACKSIZE 20000
@@ -45,11 +50,22 @@ void initGc(Int hpSize,NodePtr *ihp,Int
{
Int totalSize = hpSize+spSize;
Int tableSize = (totalSize+WORDSIZE)/(WORDSIZE+1)+1; /* Last one for end of marked */
+ int size = (int)totalSize * sizeof(Node);
- if(NULL == (hpStart = malloc ((int)totalSize * sizeof(Node)))) {
- fprintf(stderr,"Not enough memory for heap and stack.\n");
- exit(-1);
- }
+ /* Ask for memory well below the 0x80000000 line. The nhc runtime
+ * reserves the high bit on addresses for its own purposes */
+ hpStart = mmap((void *)0x40000000, size,
+ PROT_EXEC|PROT_READ|PROT_WRITE,
+ MAP_PRIVATE|MAP_ANON, -1 , 0);
+
+ if (hpStart == MAP_FAILED) {
+ if (errno == ENOMEM) {
+ fprintf(stderr,"initGc: out of memory (requested %lu bytes)", size);
+ exit(-1);
+ } else {
+ fprintf(stderr, "initGc: mmap failed: %s", strerror(errno));
+ }
+ }
hpEnd = hpStart + totalSize;
