1  /* Test that glibc.malloc.mxfast tunable works.
       2     Copyright (C) 2019-2023 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 <libc-diag.h>
      25  #include <support/check.h>
      26  
      27  int
      28  do_test (void)
      29  {
      30    struct mallinfo m;
      31    char *volatile p1;
      32    char *volatile p2;
      33  
      34    /* Arbitrary value; must be in default fastbin range.  */
      35    p1 = malloc (3);
      36    /* Something large so that p1 isn't a "top block" */
      37    p2 = malloc (512);
      38    free (p1);
      39  
      40    /* The test below covers the deprecated mallinfo function.  */
      41    DIAG_PUSH_NEEDS_COMMENT;
      42    DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wdeprecated-declarations");
      43  
      44    m = mallinfo ();
      45  
      46    DIAG_POP_NEEDS_COMMENT;
      47  
      48    /* This will fail if there are any blocks in the fastbins.  */
      49    TEST_COMPARE (m.smblks, 0);
      50  
      51    /* To keep gcc happy.  */
      52    free (p2);
      53  
      54    return 0;
      55  }
      56  
      57  #include <support/test-driver.c>