Ticket #395: fix_hint.patch

uspace/lib/c/generic/malloc.c

@@ -683 +683 @@
                 return NULL;
         
         size_t falign = lcm(align, BASE_ALIGN);
-        size_t real_size = GROSS_SIZE(ALIGN_UP(size, falign));
+
+        /*
+         * This is minimal block size where we can allocate in.
+         * The alignment is checked in malloc_area().
+         */
+        size_t real_size = GROSS_SIZE(size);
+        /*
+         * When growing the heap, we need to allocate at least this much
+         * space.
+         * Generally, to allocate x bytes aligned at y, we need at least
+         * space x + y bytes.
+         * Here we add some extra space (through ALIGN_UP(..., BASE_ALIGN))
+         * just to be on the safe side.
+         * Notice that we need to take care of all structures as growing
+         * the heap might bring a new AS area.
+         */
+        size_t grow_size = ALIGN_UP(sizeof(heap_area_t), BASE_ALIGN)
+            + ALIGN_UP(sizeof(heap_block_head_t), BASE_ALIGN)
+            + falign
+            + ALIGN_UP(size, BASE_ALIGN)
+            + ALIGN_UP(sizeof(heap_block_foot_t), BASE_ALIGN);
         
         bool retry = false;
         heap_block_head_t *split;
@@ -716 +736 @@
         
         if (!retry) {
                 /* Try to grow the heap space */
-                if (heap_grow(real_size)) {
+                if (heap_grow(grow_size)) {
                         retry = true;
                         goto loop;
                 }