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

[Glenn Washburn]

On Tue, 12 Oct 2021 18:29:56 +1100
Daniel Axtens <dja@axtens.net> 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.

Perhaps note here that the questions are "up to 4GB".

> 
> 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?
> ---
>  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
> +
> +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);
> +#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();
> +#endif
> +
> +  return 0;
> +}
> +
> +
> +#define BIG_ALLOC (64 * 1024 * 1024)
> +#define SMALL_ALLOC 32

Where are these used? A search is coming up with nothing.

> +
> +static grub_err_t
> +grub_cmd_stress_big_allocs (grub_command_t cmd __attribute__ ((unused)),
> +                         int argc __attribute__ ((unused)),
> +                         char **args __attribute__ ((unused)))

I'm thinking this would be valuable to be included in the functional
tests. What do you think?

> +{
> +  int i, max_mb, blocks_alloced;
> +  void *mem;
> +  void **blocklist;
> +
> +  grub_printf ("Test 1: increasingly sized allocs to 1GB block\n");

Perhaps, "Test 1: Allocate and free up from 1MB to 1GB in 1MB
increments."

> +  for (i = 1; i < 1024; i++) {
> +    grub_printf ("%d MB . ", i);
> +    mem = grub_malloc (i * 1024 * 1024);
> +    if (mem == NULL)
> +      {
> +     grub_printf ("failed\n");

"Failed to allocate a %dMB continuous block of memory.\n"

> +     break;
> +      }
> +    else
> +      grub_free (mem);
> +
> +    if (i % 10 == 0)
> +      grub_printf ("\n");

So every 10Mb a newline is output. That's seems small, if you've got
generally at least 80 char with terminal. Why not make it 64 and thus
evenly divide 1024?

> +  }
> +
> +  max_mb = i - 1;
> +  grub_printf ("Max sized allocation we did was %d MB\n", max_mb);
> +  

Line with just a space, should be empty.

> +  grub_printf ("Test 2: 1MB at a time, max 4GB\n");

"Test 2: Allocate total of 4GB of memory in 1MB chunks"

> +  blocklist = grub_calloc (4096, sizeof (void *));
> +  for (i = 0; i < 4096; i++)
> +    {
> +      blocklist[i] = grub_malloc (1024 * 1024);
> +      if (!blocklist[i])
> +     {
> +       grub_printf ("Ran out of memory at iteration %d\n", i);

"Failed to allocate 1MB memory chunk on block %d of 4096"

> +       break;
> +     }
> +    }
> +  blocks_alloced = i;
> +  for (i = 0; i < blocks_alloced; i++)
> +    grub_free (blocklist[i]);
> +
> +  grub_printf ("\nTest 3: 1MB aligned 900kB + 100kB\n");

"Test 3: Allocate total of 4Gb of memory in 1MB aligned 900kB + 100kB
chunks"

> +  //grub_mm_debug=1;

Was this comment intended to be included? If so, why here?

> +  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 (".");
> +    }
> +  for (i = 0; i < blocks_alloced; i++)
> +    grub_free (blocklist[i]);
> +
> +  grub_free (blocklist);
> +
> +  grub_errno = GRUB_ERR_NONE;
> +  return GRUB_ERR_NONE;
> +}
> +
> +static grub_command_t cmd_lsmem, cmd_lsfreemem, cmd_sba;
> +
> +#endif /* MM_DEBUG */
> +
> +GRUB_MOD_INIT(memtools)
> +{
> +#ifdef MM_DEBUG
> +  cmd_lsmem = grub_register_command ("lsmem", grub_cmd_lsmem,
> +                                  0, N_("List free and allocated memory 
> blocks."));
> +  cmd_lsfreemem = grub_register_command ("lsfreemem", grub_cmd_lsfreemem,
> +                                      0, N_("List free memory blocks."));
> +  cmd_sba = grub_register_command ("stress_big_allocs", 
> grub_cmd_stress_big_allocs,
> +                                0, N_("Stress test large allocations."));

Leading space characters.

> +#endif
> +}
> +
> +GRUB_MOD_FINI(memtools)
> +{
> +#ifdef MM_DEBUG
> +  grub_unregister_command (cmd_lsmem);
> +  grub_unregister_command (cmd_lsfreemem);
> +  grub_unregister_command (cmd_sba);
> +#endif
> +}
> diff --git a/grub-core/kern/mm.c b/grub-core/kern/mm.c
> index 835ed8a8f6f9..032c8f71aed2 100644
> --- a/grub-core/kern/mm.c
> +++ b/grub-core/kern/mm.c
> @@ -556,6 +556,8 @@ grub_mm_dump_free (void)
>      {
>        grub_mm_header_t p;
>  
> +      grub_printf ("Region %p (size %" PRIuGRUB_SIZE ")\n\n", r, r->size);
> +
>        /* Follow the free list.  */
>        p = r->first;
>        do
> @@ -583,6 +585,8 @@ grub_mm_dump (unsigned lineno)
>      {
>        grub_mm_header_t p;
>  
> +      grub_printf ("Region %p (size %" PRIuGRUB_SIZE ")\n\n", r, r->size);
> +
>        for (p = (grub_mm_header_t) ALIGN_UP ((grub_addr_t) (r + 1),
>                                           GRUB_MM_ALIGN);
>          (grub_addr_t) p < (grub_addr_t) (r+1) + r->size;
> diff --git a/include/grub/mm.h b/include/grub/mm.h
> index 9c38dd3ca5d2..44fde7cb9033 100644
> --- a/include/grub/mm.h
> +++ b/include/grub/mm.h
> @@ -46,8 +46,8 @@ void grub_mm_check_real (const char *file, int line);
>  /* Set this variable to 1 when you want to trace all memory function calls.  
> */
>  extern int EXPORT_VAR(grub_mm_debug);
>  
> -void grub_mm_dump_free (void);
> -void grub_mm_dump (unsigned lineno);
> +void EXPORT_FUNC(grub_mm_dump_free) (void);
> +void EXPORT_FUNC(grub_mm_dump) (unsigned lineno);

This makes me wonder if we could easily move grub_mm_dump and
grub_mm_dump_free to memtools.c, and always have them built and lsmem
and lsmemfree as well. IOW, lsmem would work without need to compile
with --enable-mm-debug. If so, since its compiled as a module there's
not an issue of it increasing the core size.

>  
>  #define grub_calloc(nmemb, size)     \
>    grub_debug_calloc (GRUB_FILE, __LINE__, nmemb, size)

Glenn