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[PATCH] drm/test: reduce stack size in drm_exec_test

Arnd Bergmann posted 1 patch 4 months ago 
drivers/gpu/drm/tests/drm_exec_test.c | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)
[PATCH] drm/test: reduce stack size in drm_exec_test
Posted by Arnd Bergmann 4 months ago 
From: Arnd Bergmann <arnd@arndb.de>

test_prepare_array() is one of the functions that uses more than
a kilobyte of stack on 64-bit machines, though it stays under
the usual warning limit of 2KB:

drivers/gpu/drm/tests/drm_exec_test.c: In function 'test_prepare_array':
drivers/gpu/drm/tests/drm_exec_test.c:171:1: error: the frame size of 1304 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]

In order to eventually lower that limit, change the two large
drm_gem_object objects to be statically allocated. This works here
because the tests are always called sequentially, and it is simpler than
using kzalloc().

Fixes: 9710631cc8f3 ("drm: add drm_exec selftests v4")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/tests/drm_exec_test.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/tests/drm_exec_test.c b/drivers/gpu/drm/tests/drm_exec_test.c
index d6c4dd1194a0..f2ac06a07707 100644
--- a/drivers/gpu/drm/tests/drm_exec_test.c
+++ b/drivers/gpu/drm/tests/drm_exec_test.c
@@ -18,6 +18,8 @@
 
 #include "../lib/drm_random.h"
 
+static struct drm_gem_object gobj, gobj2;
+
 struct drm_exec_priv {
 	struct device *dev;
 	struct drm_device *drm;
@@ -54,7 +56,6 @@ static void sanitycheck(struct kunit *test)
 static void test_lock(struct kunit *test)
 {
 	struct drm_exec_priv *priv = test->priv;
-	struct drm_gem_object gobj = { };
 	struct drm_exec exec;
 	int ret;
 
@@ -74,7 +75,6 @@ static void test_lock(struct kunit *test)
 static void test_lock_unlock(struct kunit *test)
 {
 	struct drm_exec_priv *priv = test->priv;
-	struct drm_gem_object gobj = { };
 	struct drm_exec exec;
 	int ret;
 
@@ -101,7 +101,6 @@ static void test_lock_unlock(struct kunit *test)
 static void test_duplicates(struct kunit *test)
 {
 	struct drm_exec_priv *priv = test->priv;
-	struct drm_gem_object gobj = { };
 	struct drm_exec exec;
 	int ret;
 
@@ -128,7 +127,6 @@ static void test_duplicates(struct kunit *test)
 static void test_prepare(struct kunit *test)
 {
 	struct drm_exec_priv *priv = test->priv;
-	struct drm_gem_object gobj = { };
 	struct drm_exec exec;
 	int ret;
 
@@ -150,13 +148,11 @@ static void test_prepare(struct kunit *test)
 static void test_prepare_array(struct kunit *test)
 {
 	struct drm_exec_priv *priv = test->priv;
-	struct drm_gem_object gobj1 = { };
-	struct drm_gem_object gobj2 = { };
-	struct drm_gem_object *array[] = { &gobj1, &gobj2 };
+	struct drm_gem_object *array[] = { &gobj, &gobj2 };
 	struct drm_exec exec;
 	int ret;
 
-	drm_gem_private_object_init(priv->drm, &gobj1, PAGE_SIZE);
+	drm_gem_private_object_init(priv->drm, &gobj, PAGE_SIZE);
 	drm_gem_private_object_init(priv->drm, &gobj2, PAGE_SIZE);
 
 	drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0);
@@ -166,7 +162,7 @@ static void test_prepare_array(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, ret, 0);
 	drm_exec_fini(&exec);
 
-	drm_gem_private_object_fini(&gobj1);
+	drm_gem_private_object_fini(&gobj);
 	drm_gem_private_object_fini(&gobj2);
 }
 
-- 
2.39.5
Re: [PATCH] drm/test: reduce stack size in drm_exec_test
Posted by Christian König 4 months ago 
On 6/10/25 11:33, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> test_prepare_array() is one of the functions that uses more than
> a kilobyte of stack on 64-bit machines, though it stays under
> the usual warning limit of 2KB:
> 
> drivers/gpu/drm/tests/drm_exec_test.c: In function 'test_prepare_array':
> drivers/gpu/drm/tests/drm_exec_test.c:171:1: error: the frame size of 1304 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]
> 
> In order to eventually lower that limit, change the two large
> drm_gem_object objects to be statically allocated. This works here
> because the tests are always called sequentially, and it is simpler than
> using kzalloc().
> 
> Fixes: 9710631cc8f3 ("drm: add drm_exec selftests v4")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Maybe kzalloc() would be cleaner, but it certainly isn't a must have.

Acked-by: Christian König <christian.koenig@amd.com>

> ---
>  drivers/gpu/drm/tests/drm_exec_test.c | 14 +++++---------
>  1 file changed, 5 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/tests/drm_exec_test.c b/drivers/gpu/drm/tests/drm_exec_test.c
> index d6c4dd1194a0..f2ac06a07707 100644
> --- a/drivers/gpu/drm/tests/drm_exec_test.c
> +++ b/drivers/gpu/drm/tests/drm_exec_test.c
> @@ -18,6 +18,8 @@
>  
>  #include "../lib/drm_random.h"
>  
> +static struct drm_gem_object gobj, gobj2;
> +
>  struct drm_exec_priv {
>  	struct device *dev;
>  	struct drm_device *drm;
> @@ -54,7 +56,6 @@ static void sanitycheck(struct kunit *test)
>  static void test_lock(struct kunit *test)
>  {
>  	struct drm_exec_priv *priv = test->priv;
> -	struct drm_gem_object gobj = { };
>  	struct drm_exec exec;
>  	int ret;
>  
> @@ -74,7 +75,6 @@ static void test_lock(struct kunit *test)
>  static void test_lock_unlock(struct kunit *test)
>  {
>  	struct drm_exec_priv *priv = test->priv;
> -	struct drm_gem_object gobj = { };
>  	struct drm_exec exec;
>  	int ret;
>  
> @@ -101,7 +101,6 @@ static void test_lock_unlock(struct kunit *test)
>  static void test_duplicates(struct kunit *test)
>  {
>  	struct drm_exec_priv *priv = test->priv;
> -	struct drm_gem_object gobj = { };
>  	struct drm_exec exec;
>  	int ret;
>  
> @@ -128,7 +127,6 @@ static void test_duplicates(struct kunit *test)
>  static void test_prepare(struct kunit *test)
>  {
>  	struct drm_exec_priv *priv = test->priv;
> -	struct drm_gem_object gobj = { };
>  	struct drm_exec exec;
>  	int ret;
>  
> @@ -150,13 +148,11 @@ static void test_prepare(struct kunit *test)
>  static void test_prepare_array(struct kunit *test)
>  {
>  	struct drm_exec_priv *priv = test->priv;
> -	struct drm_gem_object gobj1 = { };
> -	struct drm_gem_object gobj2 = { };
> -	struct drm_gem_object *array[] = { &gobj1, &gobj2 };
> +	struct drm_gem_object *array[] = { &gobj, &gobj2 };
>  	struct drm_exec exec;
>  	int ret;
>  
> -	drm_gem_private_object_init(priv->drm, &gobj1, PAGE_SIZE);
> +	drm_gem_private_object_init(priv->drm, &gobj, PAGE_SIZE);
>  	drm_gem_private_object_init(priv->drm, &gobj2, PAGE_SIZE);
>  
>  	drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0);
> @@ -166,7 +162,7 @@ static void test_prepare_array(struct kunit *test)
>  	KUNIT_EXPECT_EQ(test, ret, 0);
>  	drm_exec_fini(&exec);
>  
> -	drm_gem_private_object_fini(&gobj1);
> +	drm_gem_private_object_fini(&gobj);
>  	drm_gem_private_object_fini(&gobj2);
>  }
>

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