malloc: enable memory hotplug support

[dpdk.git] / lib / librte_eal / common / malloc_elem.c

diff --git a/lib/librte_eal/common/malloc_elem.c b/lib/librte_eal/common/malloc_elem.c
index 9db416f..ee79dcd 100644 (file)
--- a/lib/librte_eal/common/malloc_elem.c
+++ b/lib/librte_eal/common/malloc_elem.c
@@ -447,6 +447,98 @@ malloc_elem_free(struct malloc_elem *elem)
        return elem;
 }
 
+/* assume all checks were already done */
+void
+malloc_elem_hide_region(struct malloc_elem *elem, void *start, size_t len)
+{
+       struct malloc_elem *hide_start, *hide_end, *prev, *next;
+       size_t len_before, len_after;
+
+       hide_start = start;
+       hide_end = RTE_PTR_ADD(start, len);
+
+       prev = elem->prev;
+       next = elem->next;
+
+       /* we cannot do anything with non-adjacent elements */
+       if (next && next_elem_is_adjacent(elem)) {
+               len_after = RTE_PTR_DIFF(next, hide_end);
+               if (len_after >= MALLOC_ELEM_OVERHEAD + MIN_DATA_SIZE) {
+                       /* split after */
+                       split_elem(elem, hide_end);
+
+                       malloc_elem_free_list_insert(hide_end);
+               } else if (len_after >= MALLOC_ELEM_HEADER_LEN) {
+                       /* shrink current element */
+                       elem->size -= len_after;
+                       memset(hide_end, 0, sizeof(*hide_end));
+
+                       /* copy next element's data to our pad */
+                       memcpy(hide_end, next, sizeof(*hide_end));
+
+                       /* pad next element */
+                       next->state = ELEM_PAD;
+                       next->pad = len_after;
+                       next->size -= len_after;
+
+                       /* next element busy, would've been merged otherwise */
+                       hide_end->pad = len_after;
+                       hide_end->size += len_after;
+
+                       /* adjust pointers to point to our new pad */
+                       if (next->next)
+                               next->next->prev = hide_end;
+                       elem->next = hide_end;
+               } else if (len_after > 0) {
+                       RTE_LOG(ERR, EAL, "Unaligned element, heap is probably corrupt\n");
+                       return;
+               }
+       }
+
+       /* we cannot do anything with non-adjacent elements */
+       if (prev && prev_elem_is_adjacent(elem)) {
+               len_before = RTE_PTR_DIFF(hide_start, elem);
+               if (len_before >= MALLOC_ELEM_OVERHEAD + MIN_DATA_SIZE) {
+                       /* split before */
+                       split_elem(elem, hide_start);
+
+                       prev = elem;
+                       elem = hide_start;
+
+                       malloc_elem_free_list_insert(prev);
+               } else if (len_before > 0) {
+                       /*
+                        * unlike with elements after current, here we don't
+                        * need to pad elements, but rather just increase the
+                        * size of previous element, copy the old header and set
+                        * up trailer.
+                        */
+                       void *trailer = RTE_PTR_ADD(prev,
+                                       prev->size - MALLOC_ELEM_TRAILER_LEN);
+
+                       memcpy(hide_start, elem, sizeof(*elem));
+                       hide_start->size = len;
+
+                       prev->size += len_before;
+                       set_trailer(prev);
+
+                       /* update pointers */
+                       prev->next = hide_start;
+                       if (next)
+                               next->prev = hide_start;
+
+                       /* erase old trailer */
+                       memset(trailer, 0, MALLOC_ELEM_TRAILER_LEN);
+                       /* erase old header */
+                       memset(elem, 0, sizeof(*elem));
+
+                       elem = hide_start;
+               }
+       }
+
+       remove_elem(elem);
+}
+
 /*
  * attempt to resize a malloc_elem by expanding into any free space
  * immediately after it in memory.