Re: [PATCH 07/19] Add memtool module with memory allocation stress-test

[Daniel Kiper]

On Tue, Oct 12, 2021 at 06:29:56PM +1100, Daniel Axtens wrote:
> When working on memory, it's nice to be able to test your work.
>
> Add a memtest module. When compiled with --enable-mm-debug, it exposes
> 3 commands:
>
>  * lsmem - print all allocations and free space in all regions
>  * lsfreemem - print free space in all regions
>
>  * stress_big_allocs - stress test large allocations:
>   - how much memory can we allocate in one chunk?
>   - how many 1MB chunks can we allocate?
>   - check that gap-filling works with a 1MB aligned 900kB alloc + a
>      100kB alloc.
>
> Signed-off-by: Daniel Axtens <dja@axtens.net>
>
> ---
>
> I've put this as copyright IBM for now - hopefully we can conclude on
> whether we're still doing FSF copyright assignments?

It seems to me we should do it. In the worst case, I think, we can put
IBM and FSF copyright into the file.

> ---
>  grub-core/Makefile.core.def   |   5 ++
>  grub-core/commands/memtools.c | 157 ++++++++++++++++++++++++++++++++++
>  grub-core/kern/mm.c           |   4 +
>  include/grub/mm.h             |   4 +-
>  4 files changed, 168 insertions(+), 2 deletions(-)
>  create mode 100644 grub-core/commands/memtools.c
>
> diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
> index 8022e1c0a794..0cc3a4a500ec 100644
> --- a/grub-core/Makefile.core.def
> +++ b/grub-core/Makefile.core.def
> @@ -2527,3 +2527,8 @@ module = {
>    common = commands/i386/wrmsr.c;
>    enable = x86;
>  };
> +
> +module = {
> +  name = memtools;
> +  common = commands/memtools.c;
> +};
> diff --git a/grub-core/commands/memtools.c b/grub-core/commands/memtools.c
> new file mode 100644
> index 000000000000..6d5778f4a1b0
> --- /dev/null
> +++ b/grub-core/commands/memtools.c
> @@ -0,0 +1,157 @@
> +/*
> + *  GRUB  --  GRand Unified Bootloader
> + *  Copyright (C) 2021  IBM Corporation
> + *
> + *  GRUB is free software: you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation, either version 3 of the License, or
> + *  (at your option) any later version.
> + *
> + *  GRUB is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <config.h>
> +#include <grub/dl.h>
> +#include <grub/misc.h>
> +#include <grub/command.h>
> +#include <grub/i18n.h>
> +#include <grub/memory.h>
> +#include <grub/mm.h>
> +
> +GRUB_MOD_LICENSE ("GPLv3+");
> +
> +#ifdef MM_DEBUG

Could we avoid this ifdefery and do everything in Makefile? Then
non-debug builds will no contain even memtools stub module.

s/memtools/memdebug/?

> +static grub_err_t
> +grub_cmd_lsmem (grub_command_t cmd __attribute__ ((unused)),
> +              int argc __attribute__ ((unused)),
> +              char **args __attribute__ ((unused)))
> +
> +{
> +#ifndef GRUB_MACHINE_EMU
> +  grub_mm_dump(0);

Missing space between function name and "(". Please fix the same
mistakes below.

> +#endif
> +
> +  return 0;
> +}
> +
> +static grub_err_t
> +grub_cmd_lsfreemem (grub_command_t cmd __attribute__ ((unused)),
> +                 int argc __attribute__ ((unused)),
> +                 char **args __attribute__ ((unused)))
> +
> +{
> +#ifndef GRUB_MACHINE_EMU
> +  grub_mm_dump_free();

Ditto...

> +#endif
> +
> +  return 0;

return GRUB_ERR_NONE

> +}
> +
> +
> +#define BIG_ALLOC (64 * 1024 * 1024)

s/BIG_ALLOC/STRESS_BIG_ALLOC/?

> +#define SMALL_ALLOC 32

s/SMALL_ALLOC/STRESS_SMALL_ALLOC/?

And could you define these constants immediately behind GRUB_MOD_LICENSE()?

> +static grub_err_t
> +grub_cmd_stress_big_allocs (grub_command_t cmd __attribute__ ((unused)),
> +                         int argc __attribute__ ((unused)),
> +                         char **args __attribute__ ((unused)))
> +{
> +  int i, max_mb, blocks_alloced;
> +  void *mem;
> +  void **blocklist;
> +
> +  grub_printf ("Test 1: increasingly sized allocs to 1GB block\n");
> +  for (i = 1; i < 1024; i++) {
> +    grub_printf ("%d MB . ", i);
> +    mem = grub_malloc (i * 1024 * 1024);
> +    if (mem == NULL)
> +      {
> +     grub_printf ("failed\n");
> +     break;
> +      }
> +    else
> +      grub_free (mem);
> +
> +    if (i % 10 == 0)
> +      grub_printf ("\n");
> +  }
> +
> +  max_mb = i - 1;

I think i is not incremented when break is executed. So, max_mb value will be 
wrong.

> +  grub_printf ("Max sized allocation we did was %d MB\n", max_mb);
> +
> +  grub_printf ("Test 2: 1MB at a time, max 4GB\n");
> +  blocklist = grub_calloc (4096, sizeof (void *));

The blocklist can be NULL here.

> +  for (i = 0; i < 4096; i++)
> +    {
> +      blocklist[i] = grub_malloc (1024 * 1024);
> +      if (!blocklist[i])

if (blocklist[i] == NULL)

And please fix similar things below...

> +     {
> +       grub_printf ("Ran out of memory at iteration %d\n", i);
> +       break;

Should not we print a dot after every 32 or 64 iterations?

> +     }
> +    }
> +  blocks_alloced = i;

Again, i value can be wrong after break.

> +  for (i = 0; i < blocks_alloced; i++)
> +    grub_free (blocklist[i]);

I think each of these tests should have separate command assigned.

> +  grub_printf ("\nTest 3: 1MB aligned 900kB + 100kB\n");
> +  //grub_mm_debug=1;

Please drop this.

> +  for (i = 0; i < 4096; i += 2)
> +    {
> +      blocklist[i] = grub_memalign (1024 * 1024, 900 * 1024);
> +      if (!blocklist[i])
> +     {
> +       grub_printf ("Failed big allocation, iteration %d\n", i);
> +       blocks_alloced = i;
> +       break;
> +     }
> +
> +      blocklist[i + 1] = grub_malloc (100 * 1024);
> +      if (!blocklist[i + 1])
> +     {
> +       grub_printf ("Failed small allocation, iteration %d\n", i);
> +       blocks_alloced = i + 1;
> +       break;
> +     }
> +      grub_printf (".");

Should not we do this every 32 or 64 iterations instead?

> +    }
> +  for (i = 0; i < blocks_alloced; i++)
> +    grub_free (blocklist[i]);
> +
> +  grub_free (blocklist);
> +
> +  grub_errno = GRUB_ERR_NONE;
> +  return GRUB_ERR_NONE;
> +}

Daniel