X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/276b2d9b83a3e3afcd449fb53a2dd8d662070036..932b32f3ce5bb1d33aff7fa54faf1229ee68eb6d:/src/xbt/mmalloc/mmalloc.c

diff --git a/src/xbt/mmalloc/mmalloc.c b/src/xbt/mmalloc/mmalloc.c
index a5a0192026..3e9bdf2034 100644
--- a/src/xbt/mmalloc/mmalloc.c
+++ b/src/xbt/mmalloc/mmalloc.c
@@ -16,18 +16,25 @@
 
 /* Prototypes for local functions */
 
-static int initialize(struct mdesc *mdp);
-static void *morecore(struct mdesc *mdp, size_t size);
-static void *align(struct mdesc *mdp, size_t size);
-
-/* Aligned allocation.  */
+static int initialize(xbt_mheap_t mdp);
+static void *register_morecore(xbt_mheap_t mdp, size_t size);
+static void *align(xbt_mheap_t mdp, size_t size);
 
+/* Allocation aligned on block boundary */
 static void *align(struct mdesc *mdp, size_t size)
 {
   void *result;
   unsigned long int adj;
 
   result = mmorecore(mdp, size);
+
+  /* if this reservation does not fill up the last block of our resa,
+   * complete the reservation by also asking for the full lastest block.
+   *
+   * Also, the returned block is aligned to the end of block (but I've
+   * no fucking idea of why, actually -- http://abstrusegoose.com/432 --
+   * but not doing so seems to lead to issues).
+   */
   adj = RESIDUAL(result, BLOCKSIZE);
   if (adj != 0) {
     adj = BLOCKSIZE - adj;
@@ -37,9 +44,9 @@ static void *align(struct mdesc *mdp, size_t size)
   return (result);
 }
 
-/* Set everything up and remember that we have.  */
-
-static int initialize(struct mdesc *mdp)
+/* Finish the initialization of the mheap. If we want to inline it
+ * properly, we need to make the align function publicly visible, too  */
+static int initialize(xbt_mheap_t mdp)
 {
   mdp->heapsize = HEAP / BLOCKSIZE;
   mdp->heapinfo = (malloc_info *)
@@ -48,18 +55,18 @@ static int initialize(struct mdesc *mdp)
     return (0);
   }
   memset((void *) mdp->heapinfo, 0, mdp->heapsize * sizeof(malloc_info));
-  mdp->heapinfo[0].free.size = 0;
-  mdp->heapinfo[0].free.next = mdp->heapinfo[0].free.prev = 0;
+  mdp->heapinfo[0].type=-1;
+  mdp->heapinfo[0].free_block.size = 0;
+  mdp->heapinfo[0].free_block.next = mdp->heapinfo[0].free_block.prev = 0;
   mdp->heapindex = 0;
   mdp->heapbase = (void *) mdp->heapinfo;
   mdp->flags |= MMALLOC_INITIALIZED;
   return (1);
 }
 
-/* Get neatly aligned memory, initializing or
-   growing the heap info table as necessary. */
-
-static void *morecore(struct mdesc *mdp, size_t size)
+/* Get neatly aligned memory from the low level layers, and register it
+ * into the heap info table as necessary. */
+static void *register_morecore(struct mdesc *mdp, size_t size)
 {
   void *result;
   malloc_info *newinfo, *oldinfo;
@@ -70,27 +77,26 @@ static void *morecore(struct mdesc *mdp, size_t size)
     return (NULL);
   }
 
-  /* Check if we need to grow the info table.  */
+  /* Check if we need to grow the info table (in a multiplicative manner)  */
   if ((size_t) BLOCK((char *) result + size) > mdp->heapsize) {
+
     newsize = mdp->heapsize;
-    while ((size_t) BLOCK((char *) result + size) > newsize) {
+    while ((size_t) BLOCK((char *) result + size) > newsize)
       newsize *= 2;
-    }
-    newinfo = (malloc_info *) align(mdp, newsize * sizeof(malloc_info));
-    if (newinfo == NULL) {
-      mmorecore(mdp, -size);
-      return (NULL);
-    }
-    memset((void *) newinfo, 0, newsize * sizeof(malloc_info));
-    memcpy((void *) newinfo, (void *) mdp->heapinfo,
-           mdp->heapsize * sizeof(malloc_info));
+
+    /* Copy old info into new location */
     oldinfo = mdp->heapinfo;
-    newinfo[BLOCK(oldinfo)].busy.type = 0;
-    newinfo[BLOCK(oldinfo)].busy.info.block.size
-        = BLOCKIFY(mdp->heapsize * sizeof(malloc_info));
-    newinfo[BLOCK(oldinfo)].busy.info.block.busy_size = size;
+    newinfo = (malloc_info *) align(mdp, newsize * sizeof(malloc_info));
+    memset(newinfo, 0, newsize * sizeof(malloc_info));
+    memcpy(newinfo, oldinfo, mdp->heapsize * sizeof(malloc_info));
     mdp->heapinfo = newinfo;
-    __mmalloc_free(mdp, (void *) oldinfo);
+
+    /* mark the space previously occupied by the block info as free by first marking it
+     * as occupied in the regular way, and then freing it */
+    newinfo[BLOCK(oldinfo)].type = 0;
+    newinfo[BLOCK(oldinfo)].busy_block.size = BLOCKIFY(mdp->heapsize * sizeof(malloc_info));
+    newinfo[BLOCK(oldinfo)].busy_block.busy_size = size;
+    mfree(mdp, (void *) oldinfo);
     mdp->heapsize = newsize;
   }
 
@@ -149,8 +155,8 @@ void *mmalloc(xbt_mheap_t mdp, size_t size)
         next->next->prev = next->prev;
       }
       block = BLOCK(result);
-      if (--mdp->heapinfo[block].busy.info.frag.nfree != 0) {
-        mdp->heapinfo[block].busy.info.frag.first =
+      if (--mdp->heapinfo[block].busy_frag.nfree != 0) {
+        mdp->heapinfo[block].busy_frag.first =
             RESIDUAL(next->next, BLOCKSIZE) >> log;
       }
 
@@ -177,9 +183,9 @@ void *mmalloc(xbt_mheap_t mdp, size_t size)
 
       /* Initialize the nfree and first counters for this block.  */
       block = BLOCK(result);
-      mdp->heapinfo[block].busy.type = log;
-      mdp->heapinfo[block].busy.info.frag.nfree = i - 1;
-      mdp->heapinfo[block].busy.info.frag.first = i - 1;
+      mdp->heapinfo[block].type = log;
+      mdp->heapinfo[block].busy_frag.nfree = i - 1;
+      mdp->heapinfo[block].busy_frag.first = i - 1;
     }
   } else {
     /* Large allocation to receive one or more blocks.
@@ -188,34 +194,39 @@ void *mmalloc(xbt_mheap_t mdp, size_t size)
        space we will have to get more memory from the system.  */
     blocks = BLOCKIFY(size);
     start = block = MALLOC_SEARCH_START;
-    while (mdp->heapinfo[block].free.size < blocks) {
-      block = mdp->heapinfo[block].free.next;
+    while (mdp->heapinfo[block].free_block.size < blocks) {
+    	if (mdp->heapinfo[block].type >=0) {
+    		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;
       if (block == start) {
         /* Need to get more from the system.  Check to see if
            the new core will be contiguous with the final free
            block; if so we don't need to get as much.  */
-        block = mdp->heapinfo[0].free.prev;
-        lastblocks = mdp->heapinfo[block].free.size;
+        block = mdp->heapinfo[0].free_block.prev;
+        lastblocks = mdp->heapinfo[block].free_block.size;
         if (mdp->heaplimit != 0 &&
             block + lastblocks == mdp->heaplimit &&
             mmorecore(mdp, 0) == ADDRESS(block + lastblocks) &&
-            (morecore(mdp, (blocks - lastblocks) * BLOCKSIZE)) != NULL) {
+            (register_morecore(mdp, (blocks - lastblocks) * BLOCKSIZE)) != NULL) {
           /* Which block we are extending (the `final free
              block' referred to above) might have changed, if
              it got combined with a freed info table.  */
-          block = mdp->heapinfo[0].free.prev;
+          block = mdp->heapinfo[0].free_block.prev;
 
-          mdp->heapinfo[block].free.size += (blocks - lastblocks);
+          mdp->heapinfo[block].free_block.size += (blocks - lastblocks);
           continue;
         }
-        result = morecore(mdp, blocks * BLOCKSIZE);
+        result = register_morecore(mdp, blocks * BLOCKSIZE);
         if (result == NULL) {
           return (NULL);
         }
         block = BLOCK(result);
-        mdp->heapinfo[block].busy.type = 0;
-        mdp->heapinfo[block].busy.info.block.size = blocks;
-	mdp->heapinfo[block].busy.info.block.busy_size = size;
+        mdp->heapinfo[block].type = 0;
+        mdp->heapinfo[block].busy_block.size = blocks;
+	mdp->heapinfo[block].busy_block.busy_size = size;
         return (result);
       }
     }
@@ -223,30 +234,30 @@ void *mmalloc(xbt_mheap_t mdp, size_t size)
     /* At this point we have found a suitable free list entry.
        Figure out how to remove what we need from the list. */
     result = ADDRESS(block);
-    if (mdp->heapinfo[block].free.size > blocks) {
+    if (mdp->heapinfo[block].free_block.size > blocks) {
       /* The block we found has a bit left over,
          so relink the tail end back into the free list. */
-      mdp->heapinfo[block + blocks].free.size
-          = mdp->heapinfo[block].free.size - blocks;
-      mdp->heapinfo[block + blocks].free.next
-          = mdp->heapinfo[block].free.next;
-      mdp->heapinfo[block + blocks].free.prev
-          = mdp->heapinfo[block].free.prev;
-      mdp->heapinfo[mdp->heapinfo[block].free.prev].free.next
-          = mdp->heapinfo[mdp->heapinfo[block].free.next].free.prev
+      mdp->heapinfo[block + blocks].free_block.size
+          = mdp->heapinfo[block].free_block.size - blocks;
+      mdp->heapinfo[block + blocks].free_block.next
+          = mdp->heapinfo[block].free_block.next;
+      mdp->heapinfo[block + blocks].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;
     } else {
       /* The block exactly matches our requirements,
          so just remove it from the list. */
-      mdp->heapinfo[mdp->heapinfo[block].free.next].free.prev
-          = mdp->heapinfo[block].free.prev;
-      mdp->heapinfo[mdp->heapinfo[block].free.prev].free.next
-          = mdp->heapindex = mdp->heapinfo[block].free.next;
+      mdp->heapinfo[mdp->heapinfo[block].free_block.next].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->heapinfo[block].busy.type = 0;
-    mdp->heapinfo[block].busy.info.block.size = blocks;
-    mdp->heapinfo[block].busy.info.block.busy_size = size;
+    mdp->heapinfo[block].type = 0;
+    mdp->heapinfo[block].busy_block.size = blocks;
+    mdp->heapinfo[block].busy_block.busy_size = size;
   }
   //printf("(%s) Done mallocing. Result is %p\n",xbt_thread_self_name(),result);fflush(stdout);
   return (result);