further little clarifications in mmalloc comments

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

diff --git a/src/xbt/mmalloc/mmalloc.c b/src/xbt/mmalloc/mmalloc.c
index a3d29c4..82876e5 100644 (file)
--- 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 *)
@@ -56,10 +63,9 @@ static int initialize(struct mdesc *mdp)
   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;
@@ -100,9 +106,8 @@ static void *morecore(struct mdesc *mdp, size_t size)
 
 /* Allocate memory from the heap.  */
 
-void *mmalloc(void *md, size_t size)
+void *mmalloc(xbt_mheap_t mdp, size_t size)
 {
-  struct mdesc *mdp;
   void *result;
   size_t block, blocks, lastblocks, start;
   register size_t i;
@@ -115,7 +120,6 @@ void *mmalloc(void *md, size_t size)
   if (size == 0)
     size = 1;
 
-  mdp = MD_TO_MDP(md);
 //  printf("(%s) Mallocing %d bytes on %p (default: %p)...",xbt_thread_self_name(),size,mdp,__mmalloc_default_mdp);fflush(stdout);
 
   if (!(mdp->flags & MMALLOC_INITIALIZED)) {
@@ -160,7 +164,7 @@ void *mmalloc(void *md, size_t size)
       /* 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(md, BLOCKSIZE);
+      result = mmalloc(mdp, BLOCKSIZE);
       //printf("(%s) Fragment: %p...",xbt_thread_self_name(),result);
       if (result == NULL) {
         return (NULL);
@@ -201,7 +205,7 @@ void *mmalloc(void *md, size_t 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.  */
@@ -210,7 +214,7 @@ void *mmalloc(void *md, size_t size)
           mdp->heapinfo[block].free.size += (blocks - lastblocks);
           continue;
         }
-        result = morecore(mdp, blocks * BLOCKSIZE);
+        result = register_morecore(mdp, blocks * BLOCKSIZE);
         if (result == NULL) {
           return (NULL);
         }