malloc: Use _int_free_chunk for remaindersHEADmaster

When splitting a chunk, release the tail part by calling int_free_chunk.
This avoids inserting random blocks into tcache that were never requested
by the user.  Fragmentation will be worse if they are never used again.
Note if the tail is fairly small, we could avoid splitting it at all.
Also remove an oddly placed initialization of tcache in _libc_realloc.

Reviewed-by: DJ Delorie <dj@redhat.com>

1 files changed, 6 insertions, 9 deletions

diff --git a/malloc/malloc.c b/malloc/malloc.c
index b73ddbf..0811061 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -2646,7 +2646,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
 			CHUNK_HDR_SZ | PREV_INUSE);
               set_foot (chunk_at_offset (old_top, old_size), CHUNK_HDR_SZ);
               set_head (old_top, old_size | PREV_INUSE | NON_MAIN_ARENA);
-              _int_free (av, old_top, 1);
+              _int_free_chunk (av, old_top, chunksize (old_top), 1);
             }
           else
             {
@@ -2912,7 +2912,7 @@ sysmalloc (INTERNAL_SIZE_T nb, mstate av)
                       /* If possible, release the rest. */
                       if (old_size >= MINSIZE)
                         {
-                          _int_free (av, old_top, 1);
+                          _int_free_chunk (av, old_top, chunksize (old_top), 1);
                         }
                     }
                 }
@@ -3530,10 +3530,7 @@ __libc_realloc (void *oldmem, size_t bytes)
   if (chunk_is_mmapped (oldp))
     ar_ptr = NULL;
   else
-    {
-      MAYBE_INIT_TCACHE ();
-      ar_ptr = arena_for_chunk (oldp);
-    }
+    ar_ptr = arena_for_chunk (oldp);
 
   /* Little security check which won't hurt performance: the allocator
      never wraps around at the end of the address space.  Therefore
@@ -3608,7 +3605,7 @@ __libc_realloc (void *oldmem, size_t bytes)
 	  size_t sz = memsize (oldp);
 	  memcpy (newp, oldmem, sz);
 	  (void) tag_region (chunk2mem (oldp), sz);
-          _int_free (ar_ptr, oldp, 0);
+          _int_free_chunk (ar_ptr, oldp, chunksize (oldp), 0);
         }
     }
 
@@ -5059,7 +5056,7 @@ _int_realloc (mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize,
 	      (void) tag_region (oldmem, sz);
 	      newmem = tag_new_usable (newmem);
 	      memcpy (newmem, oldmem, sz);
-	      _int_free (av, oldp, 1);
+	      _int_free_chunk (av, oldp, chunksize (oldp), 1);
 	      check_inuse_chunk (av, newp);
 	      return newmem;
             }
@@ -5087,7 +5084,7 @@ _int_realloc (mstate av, mchunkptr oldp, INTERNAL_SIZE_T oldsize,
                 (av != &main_arena ? NON_MAIN_ARENA : 0));
       /* Mark remainder as inuse so free() won't complain */
       set_inuse_bit_at_offset (remainder, remainder_size);
-      _int_free (av, remainder, 1);
+      _int_free_chunk (av, remainder, chunksize (remainder), 1);
     }
 
   check_inuse_chunk (av, newp);