set size to -1 for free fragments in new fragmented block

[simgrid.git] / src / xbt / mmalloc / mmalloc.c

diff --git a/src/xbt/mmalloc/mmalloc.c b/src/xbt/mmalloc/mmalloc.c
index ce35d8a..c54fb4c 100644 (file)
--- a/src/xbt/mmalloc/mmalloc.c
+++ b/src/xbt/mmalloc/mmalloc.c
@@ -106,8 +106,15 @@ static void *register_morecore(struct mdesc *mdp, size_t size)
 }
 
 /* Allocate memory from the heap.  */
-
-void *mmalloc(xbt_mheap_t mdp, size_t size)
+void *mmalloc(xbt_mheap_t mdp, size_t size) {
+  void *res= mmalloc_no_memset(mdp,size);
+  memset(res,0,size);
+  return res;
+}
+/* Spliting mmalloc this way is mandated by a trick in mrealloc, that gives
+   back the memory of big blocks to the system before reallocating them: we don't
+   want to loose the beginning of the area when this happens */
+void *mmalloc_no_memset(xbt_mheap_t mdp, size_t size)
 {
   void *result;
   size_t block, blocks, lastblocks, start;
@@ -161,7 +168,7 @@ void *mmalloc(xbt_mheap_t mdp, size_t size)
       }
       if (--mdp->heapinfo[block].busy_frag.nfree != 0) {
         mdp->heapinfo[block].busy_frag.first =
-    RESIDUAL(next->next, BLOCKSIZE) >> log;
+          RESIDUAL(next->next, BLOCKSIZE) >> log;
       }
 
       /* Update the statistics.  */
@@ -170,20 +177,17 @@ void *mmalloc(xbt_mheap_t mdp, size_t size)
       mdp -> heapstats.chunks_free--;
       mdp -> heapstats.bytes_free -= 1 << log;
 
-      memset(result, 0, requested_size);
-      
     } else {
       /* No free fragments of the desired size, so get a new block
          and break it into fragments, returning the first.  */
       //printf("(%s) No free fragment...",xbt_thread_self_name());
 
       result = mmalloc(mdp, BLOCKSIZE); // does not return NULL
-      memset(result, 0, requested_size);
 
-      /* Link all fragments but the first into the free list, and mark their requested size to 0.  */
+      /* Link all fragments but the first into the free list, and mark their requested size to -1.  */
       block = BLOCK(result);
       for (i = 1; i < (size_t) (BLOCKSIZE >> log); ++i) {
-      mdp->heapinfo[block].busy_frag.frag_size[i] = 0;
+        mdp->heapinfo[block].busy_frag.frag_size[i] = -1;
         next = (struct list *) ((char *) result + (i << log));
         next->next = mdp->fraghead[log].next;
         next->prev = &mdp->fraghead[log];
@@ -213,8 +217,8 @@ void *mmalloc(xbt_mheap_t mdp, size_t size)
     start = block = MALLOC_SEARCH_START;
     while (mdp->heapinfo[block].free_block.size < blocks) {
       if (mdp->heapinfo[block].type >=0) { // Don't trust xbt_die and friends in malloc-level library, you fool!
-  fprintf(stderr,"Internal error: found a free block not marked as such (block=%lu type=%lu). Please report this bug.\n",(unsigned long)block,(unsigned long)mdp->heapinfo[block].type);
-  abort();
+        fprintf(stderr,"Internal error: found a free block not marked as such (block=%lu type=%lu). Please report this bug.\n",(unsigned long)block,(unsigned long)mdp->heapinfo[block].type);
+        abort();
       }
 
       block = mdp->heapinfo[block].free_block.next;
@@ -237,16 +241,16 @@ void *mmalloc(xbt_mheap_t mdp, size_t size)
           continue;
         }
         result = register_morecore(mdp, blocks * BLOCKSIZE);
-  memset(result, 0, requested_size);
 
         block = BLOCK(result);
-        for (it=0;it<blocks;it++)
-    mdp->heapinfo[block+it].type = 0;
+        for (it=0;it<blocks;it++){
+          mdp->heapinfo[block+it].type = 0;
+        }
         mdp->heapinfo[block].busy_block.size = blocks;
         mdp->heapinfo[block].busy_block.busy_size = requested_size;
         mdp->heapinfo[block].busy_block.bt_size=xbt_backtrace_no_malloc(mdp->heapinfo[block].busy_block.bt,XBT_BACKTRACE_SIZE);
-  mdp -> heapstats.chunks_used++;
-  mdp -> heapstats.bytes_used += blocks * BLOCKSIZE;
+        mdp -> heapstats.chunks_used++;
+        mdp -> heapstats.bytes_used += blocks * BLOCKSIZE;
         return result;
       }
       /* Need large block(s), but found some in the existing heap */
@@ -259,25 +263,26 @@ void *mmalloc(xbt_mheap_t mdp, size_t size)
       /* The block we found has a bit left over,
          so relink the tail end back into the free list. */
       mdp->heapinfo[block + blocks].free_block.size
-  = mdp->heapinfo[block].free_block.size - blocks;
+        = mdp->heapinfo[block].free_block.size - blocks;
       mdp->heapinfo[block + blocks].free_block.next
-  = mdp->heapinfo[block].free_block.next;
+        = mdp->heapinfo[block].free_block.next;
       mdp->heapinfo[block + blocks].free_block.prev
-  = mdp->heapinfo[block].free_block.prev;
+        = mdp->heapinfo[block].free_block.prev;
       mdp->heapinfo[mdp->heapinfo[block].free_block.prev].free_block.next
-  = mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
-  = mdp->heapindex = block + blocks;
+        = mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
+        = mdp->heapindex = block + blocks;
     } else {
       /* The block exactly matches our requirements,
          so just remove it from the list. */
       mdp->heapinfo[mdp->heapinfo[block].free_block.next].free_block.prev
-  = mdp->heapinfo[block].free_block.prev;
+        = mdp->heapinfo[block].free_block.prev;
       mdp->heapinfo[mdp->heapinfo[block].free_block.prev].free_block.next
-  = mdp->heapindex = mdp->heapinfo[block].free_block.next;
+        = mdp->heapindex = mdp->heapinfo[block].free_block.next;
     }
 
-    for (it=0;it<blocks;it++)
+    for (it=0;it<blocks;it++){
       mdp->heapinfo[block+it].type = 0;
+    }
     mdp->heapinfo[block].busy_block.size = blocks;
     mdp->heapinfo[block].busy_block.busy_size = requested_size;
     //mdp->heapinfo[block].busy_block.bt_size = 0;
@@ -286,6 +291,7 @@ void *mmalloc(xbt_mheap_t mdp, size_t size)
     mdp -> heapstats.chunks_used++;
     mdp -> heapstats.bytes_used += blocks * BLOCKSIZE;
     mdp -> heapstats.bytes_free -= blocks * BLOCKSIZE;
+
   }
   //printf("(%s) Done mallocing. Result is %p\n",xbt_thread_self_name(),result);fflush(stdout);
   return (result);