Re: [PATCH i-g-t 6/8] dmem: add test for current/max

[Kamil Konieczny <kamil.konieczny@linux.intel.com>]

Hi Thadeu,
On 2026-05-12 at 18:51:53 -0300, Thadeu Lima de Souza Cascardo wrote:
> Add a test that checks for current usage after VRAM allocation and release.
> Set max to different values and track that current usage is not above max,
> given some slack.
> 
> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
> ---
>  tests/drv_dmem_cgroups.c | 136 ++++++++++++++++++++++++++++++++++++++-

When you make a change in test only, add a prefix tests/a_test_name_here:
so in subject there will be:

[PATCH i-g-t 6/8] tests/drv_dmem_cgroups: add test for current/max

Btw I see below only 'current' subtest, where is 'max'?

>  1 file changed, 133 insertions(+), 3 deletions(-)
> 
> diff --git a/tests/drv_dmem_cgroups.c b/tests/drv_dmem_cgroups.c
> index 0e26b7e2bb9a..43331117854c 100644
> --- a/tests/drv_dmem_cgroups.c
> +++ b/tests/drv_dmem_cgroups.c
> @@ -223,12 +223,142 @@ static void test_write_eviction(int fd, unsigned int flags, const struct igt_dme
>  	igt_cgroup_free(cg);
>  }
>  
> +static int allocate_vram(const struct igt_dmem_driver *drv, void *ctx, int fd, int max_bo, size_t len)
> +{
> +	int n_bo, err = 0;
> +	for (n_bo = 0; n_bo < max_bo; n_bo++) {
> +		err = drv->allocate_vram(ctx, n_bo, len);
> +		if (err)
> +			break;
> +	}
> +	return err ?: n_bo;
> +}
> +
> +static void test_current(int fd, unsigned int flags, const struct igt_dmem_driver *drv)
> +{
> +	struct igt_cgroup *cg;
> +	char *cg_region;
> +	void *ctx;
> +	uint64_t current, capacity, cg_max;
> +	int n_bo = 0, max_bo;
> +	int err;
> +
> +	cg_region = drv->get_region_name(fd);
> +	igt_require_f(cg_region, "Region not tracked by dmem cgroup controller\n");
> +
> +	/* Check dmem cgroup controller is available before doing anything else */
> +	igt_require_f(igt_cgroup_dmem_available(),
> +		      "dmem cgroup controller not available (no cgroup v2 or no registered regions)\n");
> +
> +	igt_cgroup_dmem_get_capacity(cg_region, &capacity);
> +	igt_require_f(capacity >= 4 * BO_SIZE,
> +		      "VRAM capacity (%"PRIu64" MiB) too small to test\n",
> +		      capacity / SZ_1M);
> +
> +	/*
> +	 * Use up to 4 GiB, or the full capacity if the device has less.
> +	 * Leave one BO_SIZE worth of headroom so the device isn't completely
> +	 * exhausted before the cgroup limit is hit.
> +	 */
> +	cg_max = min(MAX_LIMIT, capacity - BO_SIZE);
> +	cg_max = ALIGN_DOWN(cg_max, EVICT_STEP);
> +
> +	if (flags & TEST_INTERRUPTIBLE)
> +		install_sigcont_counter();
> +
> +	/* Create cgroup and move into it */
> +	cg = igt_cgroup_new("igt_cgroups_test");
> +	igt_cgroup_move_current(cg);
> +
> +	max_bo = cg_max / BO_SIZE;
> +
> +	err = drv->init(&ctx, fd, max_bo);
> +	igt_assert_f(!err, "Failed to initialize driver");
> +
> +	n_bo = allocate_vram(drv, ctx, fd, max_bo, BO_SIZE);
> +	igt_assert_f(n_bo > 0, "failed to allocate VRAM\n");
> +
> +	igt_cgroup_dmem_get_current(cg, cg_region, &current);
> +	igt_debug("After fill: cgroup current = %"PRIu64" MiB, "
> +		  "max = %"PRIu64" MiB\n",
> +		  current / SZ_1M, cg_max / SZ_1M);
> +	igt_assert_f(current < cg_max + USAGE_SLACK && current > cg_max - USAGE_SLACK,
> +		     "current usage (%"PRIu64" MiB) is not within margin of allocation (%"PRIu64" MiB)\n",
> +		     current / SZ_1M, cg_max / SZ_1M);
> +
> +	drv->free_vram(ctx, n_bo, BO_SIZE);
> +	sleep(1);
> +
> +	igt_cgroup_dmem_get_current(cg, cg_region, &current);
> +	igt_debug("After free: cgroup current = %"PRIu64" MiB, "
> +		  "max = %"PRIu64" MiB\n",
> +		  current / SZ_1M, cg_max / SZ_1M);
> +	igt_assert_f(current < USAGE_SLACK,
> +		     "current usage (%"PRIu64" MiB) is not within margin (%d MiB)\n",
> +		     current / SZ_1M, USAGE_SLACK / SZ_1M);
> +
> +	igt_cgroup_dmem_set_max(cg, cg_region, 2 * BO_SIZE);
> +
> +	n_bo = allocate_vram(drv, ctx, fd, max_bo, BO_SIZE);
> +	igt_assert_f(n_bo > 0, "failed to allocate VRAM\n");
> +
> +	igt_cgroup_dmem_get_current(cg, cg_region, &current);
> +	igt_debug("After fill: cgroup current = %"PRIu64" MiB, "
> +		  "max = %"PRIu64" MiB\n",
> +		  current / SZ_1M, cg_max / SZ_1M);
> +	igt_assert_f(current < 2 * BO_SIZE + USAGE_SLACK && current > 2 * BO_SIZE - USAGE_SLACK,
> +		     "current usage (%"PRIu64" MiB) is not within margin of allocation (%"PRIu64" MiB)\n",
> +		     current / SZ_1M, cg_max / SZ_1M);
> +
> +	drv->free_vram(ctx, n_bo, BO_SIZE);
> +	sleep(1);
> +
> +	igt_cgroup_dmem_get_current(cg, cg_region, &current);
> +	igt_debug("After free: cgroup current = %"PRIu64" MiB, "
> +		  "max = %"PRIu64" MiB\n",
> +		  current / SZ_1M, cg_max / SZ_1M);
> +	igt_assert_f(current < USAGE_SLACK,
> +		     "current usage (%"PRIu64" MiB) is not within margin (%d MiB)\n",
> +		     current / SZ_1M, USAGE_SLACK / SZ_1M);
> +
> +	igt_cgroup_dmem_set_max(cg, cg_region, 0);
> +
> +	n_bo = allocate_vram(drv, ctx, fd, max_bo, BO_SIZE);
> +	igt_assert_f(n_bo != -ENOMEM, "VRAM allocation succeeded despite max set to 0\n");
> +
> +	igt_cgroup_dmem_get_current(cg, cg_region, &current);
> +	igt_debug("After fill: cgroup current = %"PRIu64" MiB, "
> +		  "max = %"PRIu64" MiB\n",
> +		  current / SZ_1M, cg_max / SZ_1M);
> +	igt_assert_f(current < USAGE_SLACK,
> +		     "current usage (%"PRIu64" MiB) is not within margin\n",
> +		     current / SZ_1M);
> +
> +	if (n_bo > 0)
> +		drv->free_vram(ctx, n_bo, BO_SIZE);
> +	sleep(1);
> +
> +	igt_cgroup_dmem_get_current(cg, cg_region, &current);
> +	igt_debug("After free: cgroup current = %"PRIu64" MiB, "
> +		  "max = %"PRIu64" MiB\n",
> +		  current / SZ_1M, cg_max / SZ_1M);
> +	igt_assert_f(current < USAGE_SLACK,
> +		     "current usage (%"PRIu64" MiB) is not within margin (%d MiB)\n",
> +		     current / SZ_1M, USAGE_SLACK / SZ_1M);
> +
> +	drv->deinit(ctx);
> +	free(cg_region);
> +	igt_cgroup_free(cg);
> +}
> +
>  static const struct {
>  	const char *name;
> +	void (*test_fn)(int fd, unsigned int flags, const struct igt_dmem_driver *drv);
>  	unsigned int flags;
>  } subtests[] = {
> -	{ "write_eviction",		0 },
> -	{ "write_eviction_interruptible",	TEST_INTERRUPTIBLE },
> +	{ "current", test_current, 0 },

For each new subetest add a corresponding SUBTEST: comment section.

Regards,
Kamil

> +	{ "write_eviction", test_write_eviction, 0 },
> +	{ "write_eviction_interruptible", test_write_eviction, TEST_INTERRUPTIBLE },
>  	{ }
>  };
>  
> @@ -259,7 +389,7 @@ int igt_main()
>  
>  			for (int i = 0; subtests[i].name; i++)
>  				igt_subtest_f("%s-%s", drivers[d].driver->name, subtests[i].name)
> -					test_write_eviction(fd, subtests[i].flags, drivers[d].driver);
> +					subtests[i].test_fn(fd, subtests[i].flags, drivers[d].driver);
>  
>  			igt_fixture() {
>  				if (fd >= 0)
> -- 
> 2.47.3
>