malloc/tst-mxfast.c

   1 /* Test that glibc.malloc.mxfast tunable works.
   2    Copyright (C) 2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 /* This test verifies that setting the glibc.malloc.mxfast tunable to
  20    zero results in free'd blocks being returned to the small bins, not
  21    the fast bins.  */
  22
  23 #include <malloc.h>
  24 #include <support/check.h>
  25
  26 int
  27 do_test (void)
  28 {
  29   struct mallinfo m;
  30   char *volatile p1;
  31   char *volatile p2;
  32
  33   /* Arbitrary value; must be in default fastbin range.  */
  34   p1 = malloc (3);
  35   /* Something large so that p1 isn't a "top block" */
  36   p2 = malloc (512);
  37   free (p1);
  38
  39   m = mallinfo ();
  40
  41   /* This will fail if there are any blocks in the fastbins.  */
  42   TEST_COMPARE (m.smblks, 0);
  43
  44   /* To keep gcc happy.  */
  45   free (p2);
  46
  47   return 0;
  48 }
  49
  50 #include <support/test-driver.c>