[Intel-gfx] [PATCH i-g-t] gem_ppgtt: Test VMA leak on context destruction

[Thomas Wood]

On 11 September 2015 at 15:31, Tvrtko Ursulin
<tvrtko.ursulin at linux.intel.com> wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>
> Test that VMAs associated with a context are cleaned up when
> contexts are destroyed.
>
> In practice this emulates the leak seen between fbcon and X server.
> Every time the X server exits we gain one VMA on the fbcon frame
> buffer object as externally visible via for example
> /sys/kernel/debug/dri/0/i915_gem_gtt.
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>  tests/gem_ppgtt.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 80 insertions(+)
>
> diff --git a/tests/gem_ppgtt.c b/tests/gem_ppgtt.c
> index 4f6df063214a..363f9d701585 100644
> --- a/tests/gem_ppgtt.c
> +++ b/tests/gem_ppgtt.c
> @@ -265,6 +265,83 @@ static void flink_and_close(void)
>         close(fd2);
>  }
>
> +static int grep_name(char *match, int to_match)

This could be added to igt_debugfs.c, as it might be useful for other tests.


> +{
> +       int fdd, ret, matched;
> +
> +       fdd = open("/sys/kernel/debug/dri/0/i915_gem_gtt", O_RDONLY);

igt_debugfs_open would be more robust here, as it checks various
locations for the debugfs and also attempts to mount it if it can't be
found.


> +       igt_assert(fdd >= 0);
> +
> +       matched = 0;
> +       do {
> +               char ch;
> +
> +               ret = read(fdd, &ch, 1);
> +               if (ret == 0)
> +                       break;
> +               igt_assert(ret == 1);
> +
> +               if (ch == match[matched])
> +                       matched++;
> +               else
> +                       matched = 0;
> +       } while (matched < to_match);

igt_debugfs_fopen is also available, which would allow the use of
getline and strstr here instead, as a slightly simpler implementation.


> +
> +       close(fdd);
> +
> +       return matched;
> +}
> +
> +static void flink_and_exit(void)
> +{
> +       uint32_t fd, fd2;
> +       uint32_t bo, flinked_bo, name;
> +       char match[100];
> +       int matched, to_match;
> +       int retry = 0;
> +       const int retries = 50;
> +
> +       fd = drm_open_any();
> +       igt_require(uses_full_ppgtt(fd));
> +
> +       bo = gem_create(fd, 4096);
> +       name = gem_flink(fd, bo);
> +
> +       to_match  = snprintf(match, sizeof(match), "(name: %u)", name);
> +       igt_assert(to_match < sizeof(match));
> +
> +       fd2 = drm_open_any();
> +
> +       flinked_bo = gem_open(fd2, name);
> +       exec_and_get_offset(fd2, flinked_bo);
> +       gem_sync(fd2, flinked_bo);
> +
> +       /* Verify looking for string works OK. */
> +       matched = grep_name(match, to_match);
> +       igt_assert_eq(matched, to_match);
> +
> +       gem_close(fd2, flinked_bo);
> +
> +       /* Close the context. */
> +       close(fd2);
> +
> +retry:
> +       /* Give cleanup some time to run. */
> +       usleep(100000);
> +
> +       /* The flinked bo VMA should have been cleared now, so list of VMAs
> +        * in debugfs should not contain the one for the imported object.
> +        */
> +       matched = grep_name(match, to_match);
> +       if (matched >= to_match && retry++ < retries)
> +               goto retry;
> +
> +       igt_assert_lt(matched, to_match);
> +
> +       gem_close(fd, bo);
> +       close(fd);
> +}
> +
>  #define N_CHILD 8
>  int main(int argc, char **argv)
>  {
> @@ -297,5 +374,8 @@ int main(int argc, char **argv)
>         igt_subtest("flink-and-close-vma-leak")
>                 flink_and_close();
>
> +       igt_subtest("flink-and-exit-vma-leak")
> +               flink_and_exit();
> +
>         igt_exit();
>  }
> --
> 2.5.1
>
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