[project @ 2004-11-10 03:20:31 by wolfgang]

Implement the mblock map for 64-bit architectures.
Fairly primitive data structure, but one 4GB-block, described by a
12-bit block map, is cached for speed.

Note that I've nuked the ia64-specific version (I think ia64 wants to
use the general 64-bit solution, too).

1 files changed, 21 insertions, 20 deletions

diff --git a/ghc/rts/MBlock.h b/ghc/rts/MBlock.h
index b44f6ddd1d..8d2a9792be 100644
--- a/ghc/rts/MBlock.h
+++ b/ghc/rts/MBlock.h
@@ -47,39 +47,40 @@ extern void * getMBlocks(nat n);
    will be quickly cached (indeed, performance measurements showed no
    measurable difference between doing the table lookup and using a
    constant comparison).
+
+   On 64-bit machines, we cache one 12-bit block map that describes
+   4096 megablocks or 4GB of memory. If HEAP_ALLOCED is called for
+   an address that is not in the cache, it calls slowIsHeapAlloced
+   (see MBlock.c) which will find the block map for the 4GB block in
+   question.
    -------------------------------------------------------------------------- */
 
+#if SIZEOF_VOID_P == 4
 extern StgWord8 mblock_map[];
 
-#if SIZEOF_VOID_P == 4
 /* On a 32-bit machine a 4KB table is always sufficient */
 # define MBLOCK_MAP_SIZE	4096
 # define MBLOCK_MAP_ENTRY(p)	((StgWord)(p) >> MBLOCK_SHIFT)
 # define HEAP_ALLOCED(p)	mblock_map[MBLOCK_MAP_ENTRY(p)]
-# define MARK_HEAP_ALLOCED(p)	(mblock_map[MBLOCK_MAP_ENTRY(p)] = 1)
-
-#elif defined(ia64_TARGET_ARCH)
-/* Instead of trying to cover the whole 64-bit address space (which would
- * require a better data structure), we assume that mmap allocates mappings
- * from the bottom of region 1, and track some portion of address space from
- * there upwards (currently 4GB). */
-# define MBLOCK_MAP_SIZE	4096
-# define MBLOCK_MAP_ENTRY(p)	(((StgWord)(p) - (1UL << 61)) >> MBLOCK_SHIFT)
-# define HEAP_ALLOCED(p)	((MBLOCK_MAP_ENTRY(p) < MBLOCK_MAP_SIZE) \
-					&& mblock_map[MBLOCK_MAP_ENTRY(p)])
-# define MARK_HEAP_ALLOCED(p)	((MBLOCK_MAP_ENTRY(p) < MBLOCK_MAP_SIZE) \
-					&& (mblock_map[MBLOCK_MAP_ENTRY(p)] = 1))
 
 #elif SIZEOF_VOID_P == 8
-/* XXX: This is a HACK, and will not work in general!  We just use the
- * lower 32 bits of the address, and do the same as for the 32-bit
- * version.  As long as the OS gives us memory in a roughly linear
- * fashion, it won't go wrong until we've allocated 4G.  */
+
 # define MBLOCK_MAP_SIZE	4096
 # define MBLOCK_MAP_ENTRY(p)	(((StgWord)(p) & 0xffffffff) >> MBLOCK_SHIFT)
-# define HEAP_ALLOCED(p)	(mblock_map[MBLOCK_MAP_ENTRY(p)])
-# define MARK_HEAP_ALLOCED(p)	(mblock_map[MBLOCK_MAP_ENTRY(p)] = 1)
 
+typedef struct {
+    StgWord32	addrHigh32;
+    StgWord8	mblocks[MBLOCK_MAP_SIZE];
+} MBlockMap;
+
+extern MBlockMap *mblock_cache;
+
+StgBool slowIsHeapAlloced(void *p);
+
+# define HEAP_ALLOCED(p)  					\
+	( ((((StgWord)(p)) >> 32) == mblock_cache->addrHigh32)	\
+	? mblock_cache->mblocks[MBLOCK_MAP_ENTRY(p)]		\
+	: slowIsHeapAlloced(p) )
 
 #else
 # error HEAP_ALLOCED not defined