malloc: Only fill half of the tcache during batch allocation

This leaves room for subsequent frees.

diff --git a/malloc/malloc.c b/malloc/malloc.c
index 99ba94454e40566eb566c8d3e8c64d55375ee634..3505158ac0f0c9ab3547d5886992853851eed60e 100644 (file)
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -3570,8 +3570,11 @@ _int_malloc (mstate av, size_t bytes)
              if (__glibc_unlikely (tcache_inactive ()))
                tcache_init (av);
 
-             /* While bin not empty and tcache not full, copy chunks over.  */
-             while (tcache->num_slots[tc_idx] != 0
+             /* While bin not empty and tcache not full, copy chunks over.
+                Only fill half of the tcache, so that subsequent frees
+                do not immediately flush the tcache.  */
+             unsigned int tcache_target_count = mp_.tcache_count / 2;
+             while (tcache->num_slots[tc_idx] > tcache_target_count
                     && (tc_victim = last (bin)) != bin)
                {
                  if (tc_victim != NULL)