Merge the smp and threaded RTS ways

[ghc-hetmet.git] / ghc / rts / BlockAlloc.c

diff --git a/ghc/rts/BlockAlloc.c b/ghc/rts/BlockAlloc.c
index e6a176b..5e0e321 100644 (file)
--- a/ghc/rts/BlockAlloc.c
+++ b/ghc/rts/BlockAlloc.c
@@ -1,7 +1,6 @@
 /* -----------------------------------------------------------------------------
- * $Id: BlockAlloc.c,v 1.8 2001/07/23 10:47:16 simonmar Exp $
  *
- * (c) The GHC Team 1998-2000
+ * (c) The GHC Team 1998-2006
  * 
  * The block allocator and free list manager.
  *
@@ -16,17 +15,22 @@
  *
  * ---------------------------------------------------------------------------*/
 
+#include "PosixSource.h"
 #include "Rts.h"
 #include "RtsFlags.h"
 #include "RtsUtils.h"
 #include "BlockAlloc.h"
 #include "MBlock.h"
+#include "Storage.h"
+
+#include <string.h>
 
 static void    initMBlock(void *mblock);
 static bdescr *allocMegaGroup(nat mblocks);
 static void    freeMegaGroup(bdescr *bd);
 
-static bdescr *free_list;
+// In THREADED_RTS mode, the free list is protected by sm_mutex.
+static bdescr *free_list = NULL;
 
 /* -----------------------------------------------------------------------------
    Initialisation
@@ -34,14 +38,14 @@ static bdescr *free_list;
 
 void initBlockAllocator(void)
 {
-  free_list = NULL;
+    // The free list starts off NULL
 }
 
 /* -----------------------------------------------------------------------------
    Allocation
    -------------------------------------------------------------------------- */
 
-static inline void
+STATIC_INLINE void
 initGroup(nat n, bdescr *head)
 {
   bdescr *bd;
@@ -49,9 +53,11 @@ initGroup(nat n, bdescr *head)
 
   if (n != 0) {
     head->blocks = n;
-    head->free = head->start;
+    head->free   = head->start;
+    head->link   = NULL;
     for (i=1, bd = head+1; i < n; i++, bd++) {
       bd->free = 0;
+      bd->blocks = 0;
       bd->link = head;
     }
   }
@@ -63,6 +69,9 @@ allocGroup(nat n)
   void *mblock;
   bdescr *bd, **last;
 
+  ASSERT_SM_LOCK();
+  ASSERT(n != 0);
+
   if (n > BLOCKS_PER_MBLOCK) {
     return allocMegaGroup(BLOCKS_TO_MBLOCKS(n));
   }
@@ -73,9 +82,8 @@ allocGroup(nat n)
       *last = bd->link;
       /* no initialisation necessary - this is already a
        * self-contained block group. */
-#ifdef DEBUG
       bd->free = bd->start;    /* block isn't free now */
-#endif
+      bd->link = NULL;
       return bd;
     }
     if (bd->blocks >  n) {     /* block too big... */
@@ -99,11 +107,31 @@ allocGroup(nat n)
 }
 
 bdescr *
+allocGroup_lock(nat n)
+{
+    bdescr *bd;
+    ACQUIRE_SM_LOCK;
+    bd = allocGroup(n);
+    RELEASE_SM_LOCK;
+    return bd;
+}
+
+bdescr *
 allocBlock(void)
 {
   return allocGroup(1);
 }
 
+bdescr *
+allocBlock_lock(void)
+{
+    bdescr *bd;
+    ACQUIRE_SM_LOCK;
+    bd = allocBlock();
+    RELEASE_SM_LOCK;
+    return bd;
+}
+
 /* -----------------------------------------------------------------------------
    Any request larger than BLOCKS_PER_MBLOCK needs a megablock group.
    First, search the free list for enough contiguous megablocks to
@@ -188,19 +216,21 @@ allocMegaGroup(nat n)
  * pointer to the newly enlarged group p.
  */
 
-static inline bdescr *
+STATIC_INLINE bdescr *
 coalesce(bdescr *p)
 {
   bdescr *bd, *q;
-  nat i;
+  nat i, blocks;
 
   q = p->link;
   if (q != NULL && p->start + p->blocks * BLOCK_SIZE_W == q->start) {
     /* can coalesce */
     p->blocks += q->blocks;
     p->link    = q->link;
-    for (i = 0, bd = q; i < q->blocks; bd++, i++) {
+    blocks = q->blocks;
+    for (i = 0, bd = q; i < blocks; bd++, i++) {
        bd->free = 0;
+       bd->blocks = 0;
        bd->link = p;
     }
     return p;
@@ -213,19 +243,20 @@ freeGroup(bdescr *p)
 {
   bdescr *bd, *last;
   
+  ASSERT_SM_LOCK();
+
   /* are we dealing with a megablock group? */
   if (p->blocks > BLOCKS_PER_MBLOCK) {
     freeMegaGroup(p);
     return;
   }
 
-#ifdef DEBUG
+
   p->free = (void *)-1;  /* indicates that this block is free */
   p->step = NULL;
   p->gen_no = 0;
   /* fill the block group with garbage if sanity checking is on */
   IF_DEBUG(sanity,memset(p->start, 0xaa, p->blocks * BLOCK_SIZE));
-#endif
 
   /* find correct place in free list to place new group */
   last = NULL;
@@ -250,16 +281,25 @@ freeGroup(bdescr *p)
   IF_DEBUG(sanity, checkFreeListSanity());
 }
 
+void
+freeGroup_lock(bdescr *p)
+{
+    ACQUIRE_SM_LOCK;
+    freeGroup(p);
+    RELEASE_SM_LOCK;
+}
+
 static void
 freeMegaGroup(bdescr *p)
 {
   nat n;
+  void *q = p;
 
-  n = p->blocks * BLOCK_SIZE / MBLOCK_SIZE + 1;
-  for (; n > 0; (W_)p += MBLOCK_SIZE, n--) {
-    initMBlock((void *)((W_)p & ~MBLOCK_MASK));
-    initGroup(BLOCKS_PER_MBLOCK, p);
-    freeGroup(p);
+  n = ((bdescr *)q)->blocks * BLOCK_SIZE / MBLOCK_SIZE + 1;
+  for (; n > 0; q += MBLOCK_SIZE, n--) {
+    initMBlock(MBLOCK_ROUND_DOWN(q));
+    initGroup(BLOCKS_PER_MBLOCK, (bdescr *)q);
+    freeGroup((bdescr *)q);
   }
 }
 
@@ -274,6 +314,14 @@ freeChain(bdescr *bd)
   }
 }
 
+void
+freeChain_lock(bdescr *bd)
+{
+    ACQUIRE_SM_LOCK;
+    freeChain(bd);
+    RELEASE_SM_LOCK;
+}
+
 static void
 initMBlock(void *mblock)
 {
@@ -288,7 +336,7 @@ initMBlock(void *mblock)
 
   /* Initialise the start field of each block descriptor
    */
-  for (; block <= LAST_BLOCK(mblock); bd += 1, (lnat)block += BLOCK_SIZE) {
+  for (; block <= LAST_BLOCK(mblock); bd += 1, block += BLOCK_SIZE) {
     bd->start = block;
   }
 }
@@ -298,6 +346,18 @@ initMBlock(void *mblock)
    -------------------------------------------------------------------------- */
 
 #ifdef DEBUG
+static void
+checkWellFormedGroup( bdescr *bd )
+{
+    nat i;
+
+    for (i = 1; i < bd->blocks; i++) {
+       ASSERT(bd[i].blocks == 0);
+       ASSERT(bd[i].free   == 0);
+       ASSERT(bd[i].link   == bd);
+    }
+}
+
 void
 checkFreeListSanity(void)
 {
@@ -305,9 +365,10 @@ checkFreeListSanity(void)
 
   for (bd = free_list; bd != NULL; bd = bd->link) {
     IF_DEBUG(block_alloc,
-            fprintf(stderr,"group at 0x%x, length %d blocks\n", 
-                    (nat)bd->start, bd->blocks));
+            debugBelch("group at 0x%p, length %d blocks\n", 
+                       bd->start, bd->blocks));
     ASSERT(bd->blocks > 0);
+    checkWellFormedGroup(bd);
     if (bd->link != NULL) {
       /* make sure we're fully coalesced */
       ASSERT(bd->start + bd->blocks * BLOCK_SIZE_W != bd->link->start);