Re: [PATCH v2] drm/i915: Import the kfence selftests for i915_sw_fence

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

Chris Wilson <chris@chris-wilson.co.uk> writes:

> A long time ago, I wrote some selftests for the struct kfence idea. Now
> that we have infrastructure in i915/igt for running kselftests, include
> some for i915_sw_fence.
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

Only minor thing that caught my eye was that I would
have preferred:

err_free_C: type of gotos instead of just err_C. In here
tho everything was straightfoward teardown of allocations
so it was clear.

Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>

> ---
>  drivers/gpu/drm/i915/Kconfig.debug                 |  12 +
>  drivers/gpu/drm/i915/i915_sw_fence.c               |   7 +-
>  .../gpu/drm/i915/selftests/i915_mock_selftests.h   |   1 +
>  drivers/gpu/drm/i915/selftests/i915_sw_fence.c     | 576 +++++++++++++++++++++
>  4 files changed, 595 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/gpu/drm/i915/selftests/i915_sw_fence.c
>
> diff --git a/drivers/gpu/drm/i915/Kconfig.debug b/drivers/gpu/drm/i915/Kconfig.debug
> index b00edd3b8800..78c5c049a347 100644
> --- a/drivers/gpu/drm/i915/Kconfig.debug
> +++ b/drivers/gpu/drm/i915/Kconfig.debug
> @@ -61,6 +61,18 @@ config DRM_I915_SW_FENCE_DEBUG_OBJECTS
>  
>            If in doubt, say "N".
>  
> +config DRM_I915_SW_FENCE_CHECK_DAG
> +        bool "Enable additional driver debugging for detecting dependency cycles"
> +        depends on DRM_I915
> +        default n
> +        help
> +          Choose this option to turn on extra driver debugging that may affect
> +          performance but will catch some internal issues.
> +
> +          Recommended for driver developers only.
> +
> +          If in doubt, say "N".
> +
>  config DRM_I915_SELFTEST
>  	bool "Enable selftests upon driver load"
>  	depends on DRM_I915
> diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c b/drivers/gpu/drm/i915/i915_sw_fence.c
> index a0a690d6627e..474d23c0c0ce 100644
> --- a/drivers/gpu/drm/i915/i915_sw_fence.c
> +++ b/drivers/gpu/drm/i915/i915_sw_fence.c
> @@ -12,6 +12,7 @@
>  #include <linux/reservation.h>
>  
>  #include "i915_sw_fence.h"
> +#include "i915_selftest.h"
>  
>  #define I915_SW_FENCE_FLAG_ALLOC BIT(3) /* after WQ_FLAG_* for safety */
>  
> @@ -274,7 +275,7 @@ static bool i915_sw_fence_check_if_after(struct i915_sw_fence *fence,
>  	unsigned long flags;
>  	bool err;
>  
> -	if (!IS_ENABLED(CONFIG_I915_SW_FENCE_CHECK_DAG))
> +	if (!IS_ENABLED(CONFIG_DRM_I915_SW_FENCE_CHECK_DAG))
>  		return false;
>  
>  	spin_lock_irqsave(&i915_sw_fence_lock, flags);
> @@ -490,3 +491,7 @@ int i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
>  
>  	return ret;
>  }
> +
> +#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
> +#include "selftests/i915_sw_fence.c"
> +#endif
> diff --git a/drivers/gpu/drm/i915/selftests/i915_mock_selftests.h b/drivers/gpu/drm/i915/selftests/i915_mock_selftests.h
> index 76c1f149a0a0..fc74687501ba 100644
> --- a/drivers/gpu/drm/i915/selftests/i915_mock_selftests.h
> +++ b/drivers/gpu/drm/i915/selftests/i915_mock_selftests.h
> @@ -9,6 +9,7 @@
>   * Tests are executed in order by igt/drv_selftest
>   */
>  selftest(sanitycheck, i915_mock_sanitycheck) /* keep first (igt selfcheck) */
> +selftest(fence, i915_sw_fence_mock_selftests)
>  selftest(scatterlist, scatterlist_mock_selftests)
>  selftest(syncmap, i915_syncmap_mock_selftests)
>  selftest(uncore, intel_uncore_mock_selftests)
> diff --git a/drivers/gpu/drm/i915/selftests/i915_sw_fence.c b/drivers/gpu/drm/i915/selftests/i915_sw_fence.c
> new file mode 100644
> index 000000000000..c552c23eecff
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/selftests/i915_sw_fence.c
> @@ -0,0 +1,576 @@
> +/*
> + * Copyright © 2017 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + *
> + */
> +
> +#include <linux/completion.h>
> +#include <linux/delay.h>
> +
> +#include "../i915_selftest.h"
> +
> +static int __i915_sw_fence_call
> +fence_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)
> +{
> +	switch (state) {
> +	case FENCE_COMPLETE:
> +		break;
> +
> +	case FENCE_FREE:
> +		/* Leave the fence for the caller to free it after testing */
> +		break;
> +	}
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static struct i915_sw_fence *alloc_fence(void)
> +{
> +	struct i915_sw_fence *fence;
> +
> +	fence = kmalloc(sizeof(*fence), GFP_KERNEL);
> +	if (!fence)
> +		return NULL;
> +
> +	i915_sw_fence_init(fence, fence_notify);
> +	return fence;
> +}
> +
> +static void free_fence(struct i915_sw_fence *fence)
> +{
> +	i915_sw_fence_fini(fence);
> +	kfree(fence);
> +}
> +
> +static int __test_self(struct i915_sw_fence *fence)
> +{
> +	if (i915_sw_fence_done(fence))
> +		return -EINVAL;
> +
> +	i915_sw_fence_commit(fence);
> +	if (!i915_sw_fence_done(fence))
> +		return -EINVAL;
> +
> +	i915_sw_fence_wait(fence);
> +	if (!i915_sw_fence_done(fence))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int test_self(void *arg)
> +{
> +	struct i915_sw_fence *fence;
> +	int ret;
> +
> +	/* Test i915_sw_fence signaling and completion testing */
> +	fence = alloc_fence();
> +	if (!fence)
> +		return -ENOMEM;
> +
> +	ret = __test_self(fence);
> +
> +	free_fence(fence);
> +	return ret;
> +}
> +
> +static int test_dag(void *arg)
> +{
> +	struct i915_sw_fence *A, *B, *C;
> +	int ret = -EINVAL;
> +
> +	/* Test detection of cycles within the i915_sw_fence graphs */
> +	if (!IS_ENABLED(CONFIG_DRM_I915_SW_FENCE_CHECK_DAG))
> +		return 0;
> +
> +	A = alloc_fence();
> +	if (!A)
> +		return -ENOMEM;
> +
> +	if (i915_sw_fence_await_sw_fence_gfp(A, A, GFP_KERNEL) != -EINVAL) {
> +		pr_err("recursive cycle not detected (AA)\n");
> +		goto err_A;
> +	}
> +
> +	B = alloc_fence();
> +	if (!B) {
> +		ret = -ENOMEM;
> +		goto err_A;
> +	}
> +
> +	i915_sw_fence_await_sw_fence_gfp(A, B, GFP_KERNEL);
> +	if (i915_sw_fence_await_sw_fence_gfp(B, A, GFP_KERNEL) != -EINVAL) {
> +		pr_err("single depth cycle not detected (BAB)\n");
> +		goto err_B;
> +	}
> +
> +	C = alloc_fence();
> +	if (i915_sw_fence_await_sw_fence_gfp(B, C, GFP_KERNEL) == -EINVAL) {
> +		pr_err("invalid cycle detected\n");
> +		goto err_C;
> +	}
> +	if (i915_sw_fence_await_sw_fence_gfp(C, B, GFP_KERNEL) != -EINVAL) {
> +		pr_err("single depth cycle not detected (CBC)\n");
> +		goto err_C;
> +	}
> +	if (i915_sw_fence_await_sw_fence_gfp(C, A, GFP_KERNEL) != -EINVAL) {
> +		pr_err("cycle not detected (BA, CB, AC)\n");
> +		goto err_C;
> +	}
> +	if (i915_sw_fence_await_sw_fence_gfp(A, C, GFP_KERNEL) == -EINVAL) {
> +		pr_err("invalid cycle detected\n");
> +		goto err_C;
> +	}
> +
> +	i915_sw_fence_commit(A);
> +	i915_sw_fence_commit(B);
> +	i915_sw_fence_commit(C);
> +
> +	ret = 0;
> +	if (!i915_sw_fence_done(C)) {
> +		pr_err("fence C not done\n");
> +		ret = -EINVAL;
> +	}
> +	if (!i915_sw_fence_done(B)) {
> +		pr_err("fence B not done\n");
> +		ret = -EINVAL;
> +	}
> +	if (!i915_sw_fence_done(A)) {
> +		pr_err("fence A not done\n");
> +		ret = -EINVAL;
> +	}
> +err_C:
> +	free_fence(C);
> +err_B:
> +	free_fence(B);
> +err_A:
> +	free_fence(A);
> +	return ret;
> +}
> +
> +static int test_AB(void *arg)
> +{
> +	struct i915_sw_fence *A, *B;
> +	int ret;
> +
> +	/* Test i915_sw_fence (A) waiting on an event source (B) */
> +	A = alloc_fence();
> +	if (!A)
> +		return -ENOMEM;
> +	B = alloc_fence();
> +	if (!B) {
> +		ret = -ENOMEM;
> +		goto err_A;
> +	}
> +
> +	ret = i915_sw_fence_await_sw_fence_gfp(A, B, GFP_KERNEL);
> +	if (ret < 0)
> +		goto err_B;
> +	if (ret == 0) {
> +		pr_err("Incorrectly reported fence A was complete before await\n");
> +		ret = -EINVAL;
> +		goto err_B;
> +	}
> +
> +	ret = -EINVAL;
> +	i915_sw_fence_commit(A);
> +	if (i915_sw_fence_done(A))
> +		goto err_B;
> +
> +	i915_sw_fence_commit(B);
> +	if (!i915_sw_fence_done(B)) {
> +		pr_err("Fence B is not done\n");
> +		goto err_B;
> +	}
> +
> +	if (!i915_sw_fence_done(A)) {
> +		pr_err("Fence A is not done\n");
> +		goto err_B;
> +	}
> +
> +	ret = 0;
> +err_B:
> +	free_fence(B);
> +err_A:
> +	free_fence(A);
> +	return ret;
> +}
> +
> +static int test_ABC(void *arg)
> +{
> +	struct i915_sw_fence *A, *B, *C;
> +	int ret;
> +
> +	/* Test a chain of fences, A waits on B who waits on C */
> +	A = alloc_fence();
> +	if (!A)
> +		return -ENOMEM;
> +
> +	B = alloc_fence();
> +	if (!B) {
> +		ret = -ENOMEM;
> +		goto err_A;
> +	}
> +
> +	C = alloc_fence();
> +	if (!C) {
> +		ret = -ENOMEM;
> +		goto err_B;
> +	}
> +
> +	ret = i915_sw_fence_await_sw_fence_gfp(A, B, GFP_KERNEL);
> +	if (ret < 0)
> +		goto err_C;
> +	if (ret == 0) {
> +		pr_err("Incorrectly reported fence B was complete before await\n");
> +		goto err_C;
> +	}
> +
> +	ret = i915_sw_fence_await_sw_fence_gfp(B, C, GFP_KERNEL);
> +	if (ret < 0)
> +		goto err_C;
> +	if (ret == 0) {
> +		pr_err("Incorrectly reported fence C was complete before await\n");
> +		goto err_C;
> +	}
> +
> +	ret = -EINVAL;
> +	i915_sw_fence_commit(A);
> +	if (i915_sw_fence_done(A)) {
> +		pr_err("Fence A completed early\n");
> +		goto err_C;
> +	}
> +
> +	i915_sw_fence_commit(B);
> +	if (i915_sw_fence_done(B)) {
> +		pr_err("Fence B completed early\n");
> +		goto err_C;
> +	}
> +
> +	if (i915_sw_fence_done(A)) {
> +		pr_err("Fence A completed early (after signaling B)\n");
> +		goto err_C;
> +	}
> +
> +	i915_sw_fence_commit(C);
> +
> +	ret = 0;
> +	if (!i915_sw_fence_done(C)) {
> +		pr_err("Fence C not done\n");
> +		ret = -EINVAL;
> +	}
> +	if (!i915_sw_fence_done(B)) {
> +		pr_err("Fence B not done\n");
> +		ret = -EINVAL;
> +	}
> +	if (!i915_sw_fence_done(A)) {
> +		pr_err("Fence A not done\n");
> +		ret = -EINVAL;
> +	}
> +err_C:
> +	free_fence(C);
> +err_B:
> +	free_fence(B);
> +err_A:
> +	free_fence(A);
> +	return ret;
> +}
> +
> +static int test_AB_C(void *arg)
> +{
> +	struct i915_sw_fence *A, *B, *C;
> +	int ret = -EINVAL;
> +
> +	/* Test multiple fences (AB) waiting on a single event (C) */
> +	A = alloc_fence();
> +	if (!A)
> +		return -ENOMEM;
> +
> +	B = alloc_fence();
> +	if (!B) {
> +		ret = -ENOMEM;
> +		goto err_A;
> +	}
> +
> +	C = alloc_fence();
> +	if (!B) {
> +		ret = -ENOMEM;
> +		goto err_B;
> +	}
> +
> +	ret = i915_sw_fence_await_sw_fence_gfp(A, C, GFP_KERNEL);
> +	if (ret < 0)
> +		goto err_C;
> +	if (ret == 0) {
> +		ret = -EINVAL;
> +		goto err_C;
> +	}
> +
> +	ret = i915_sw_fence_await_sw_fence_gfp(B, C, GFP_KERNEL);
> +	if (ret < 0)
> +		goto err_C;
> +	if (ret == 0) {
> +		ret = -EINVAL;
> +		goto err_C;
> +	}
> +
> +	i915_sw_fence_commit(A);
> +	i915_sw_fence_commit(B);
> +
> +	ret = 0;
> +	if (i915_sw_fence_done(A)) {
> +		pr_err("Fence A completed early\n");
> +		ret = -EINVAL;
> +	}
> +
> +	if (i915_sw_fence_done(B)) {
> +		pr_err("Fence B completed early\n");
> +		ret = -EINVAL;
> +	}
> +
> +	i915_sw_fence_commit(C);
> +	if (!i915_sw_fence_done(C)) {
> +		pr_err("Fence C not done\n");
> +		ret = -EINVAL;
> +	}
> +
> +	if (!i915_sw_fence_done(B)) {
> +		pr_err("Fence B not done\n");
> +		ret = -EINVAL;
> +	}
> +
> +	if (!i915_sw_fence_done(A)) {
> +		pr_err("Fence A not done\n");
> +		ret = -EINVAL;
> +	}
> +
> +err_C:
> +	free_fence(C);
> +err_B:
> +	free_fence(B);
> +err_A:
> +	free_fence(A);
> +	return ret;
> +}
> +
> +static int test_C_AB(void *arg)
> +{
> +	struct i915_sw_fence *A, *B, *C;
> +	int ret;
> +
> +	/* Test multiple event sources (A,B) for a single fence (C) */
> +	A = alloc_fence();
> +	if (!A)
> +		return -ENOMEM;
> +
> +	B = alloc_fence();
> +	if (!B) {
> +		ret = -ENOMEM;
> +		goto err_A;
> +	}
> +
> +	C = alloc_fence();
> +	if (!B) {
> +		ret = -ENOMEM;
> +		goto err_B;
> +	}
> +
> +	ret = i915_sw_fence_await_sw_fence_gfp(C, A, GFP_KERNEL);
> +	if (ret < 0)
> +		goto err_C;
> +	if (ret == 0) {
> +		ret = -EINVAL;
> +		goto err_C;
> +	}
> +
> +	ret = i915_sw_fence_await_sw_fence_gfp(C, B, GFP_KERNEL);
> +	if (ret < 0)
> +		goto err_C;
> +	if (ret == 0) {
> +		ret = -EINVAL;
> +		goto err_C;
> +	}
> +
> +	ret = 0;
> +	i915_sw_fence_commit(C);
> +	if (i915_sw_fence_done(C))
> +		ret = -EINVAL;
> +
> +	i915_sw_fence_commit(A);
> +	i915_sw_fence_commit(B);
> +
> +	if (!i915_sw_fence_done(A)) {
> +		pr_err("Fence A not done\n");
> +		ret = -EINVAL;
> +	}
> +
> +	if (!i915_sw_fence_done(B)) {
> +		pr_err("Fence B not done\n");
> +		ret = -EINVAL;
> +	}
> +
> +	if (!i915_sw_fence_done(C)) {
> +		pr_err("Fence C not done\n");
> +		ret = -EINVAL;
> +	}
> +
> +err_C:
> +	free_fence(C);
> +err_B:
> +	free_fence(B);
> +err_A:
> +	free_fence(A);
> +	return ret;
> +}
> +
> +static int test_chain(void *arg)
> +{
> +	int nfences = 4096;
> +	struct i915_sw_fence **fences;
> +	int ret, i;
> +
> +	/* Test a long chain of fences */
> +	fences = kmalloc_array(nfences, sizeof(*fences), GFP_KERNEL);
> +	if (!fences)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < nfences; i++) {
> +		fences[i] = alloc_fence();
> +		if (!fences[i]) {
> +			nfences = i;
> +			ret = -ENOMEM;
> +			goto err;
> +		}
> +
> +		if (i > 0) {
> +			ret = i915_sw_fence_await_sw_fence_gfp(fences[i],
> +							       fences[i - 1],
> +							       GFP_KERNEL);
> +			if (ret < 0) {
> +				nfences = i + 1;
> +				goto err;
> +			}
> +
> +			i915_sw_fence_commit(fences[i]);
> +		}
> +	}
> +
> +	ret = 0;
> +	for (i = nfences; --i; ) {
> +		if (i915_sw_fence_done(fences[i])) {
> +			if (ret == 0)
> +				pr_err("Fence[%d] completed early\n", i);
> +			ret = -EINVAL;
> +		}
> +	}
> +	i915_sw_fence_commit(fences[0]);
> +	for (i = 0; ret == 0 && i < nfences; i++) {
> +		if (!i915_sw_fence_done(fences[i])) {
> +			pr_err("Fence[%d] is not done\n", i);
> +			ret = -EINVAL;
> +		}
> +	}
> +
> +err:
> +	for (i = 0; i < nfences; i++)
> +		free_fence(fences[i]);
> +	kfree(fences);
> +	return ret;
> +}
> +
> +struct task_ipc {
> +	struct work_struct work;
> +	struct completion started;
> +	struct i915_sw_fence *in, *out;
> +	int value;
> +};
> +
> +static void task_ipc(struct work_struct *work)
> +{
> +	struct task_ipc *ipc = container_of(work, typeof(*ipc), work);
> +
> +	complete(&ipc->started);
> +
> +	i915_sw_fence_wait(ipc->in);
> +	smp_store_mb(ipc->value, 1);
> +	i915_sw_fence_commit(ipc->out);
> +}
> +
> +static int test_ipc(void *arg)
> +{
> +	struct task_ipc ipc;
> +	int ret = 0;
> +
> +	/* Test use of i915_sw_fence as an interprocess signaling mechanism */
> +	ipc.in = alloc_fence();
> +	if (!ipc.in)
> +		return -ENOMEM;
> +	ipc.out = alloc_fence();
> +	if (!ipc.out) {
> +		ret = -ENOMEM;
> +		goto err_in;
> +	}
> +
> +	/* use a completion to avoid chicken-and-egg testing */
> +	init_completion(&ipc.started);
> +
> +	ipc.value = 0;
> +	INIT_WORK(&ipc.work, task_ipc);
> +	schedule_work(&ipc.work);
> +
> +	wait_for_completion(&ipc.started);
> +
> +	usleep_range(1000, 2000);
> +	if (READ_ONCE(ipc.value)) {
> +		pr_err("worker updated value before i915_sw_fence was signaled\n");
> +		ret = -EINVAL;
> +	}
> +
> +	i915_sw_fence_commit(ipc.in);
> +	i915_sw_fence_wait(ipc.out);
> +
> +	if (!READ_ONCE(ipc.value)) {
> +		pr_err("worker signaled i915_sw_fence before value was posted\n");
> +		ret = -EINVAL;
> +	}
> +
> +	flush_work(&ipc.work);
> +	free_fence(ipc.out);
> +err_in:
> +	free_fence(ipc.in);
> +	return ret;
> +}
> +
> +int i915_sw_fence_mock_selftests(void)
> +{
> +	static const struct i915_subtest tests[] = {
> +		SUBTEST(test_self),
> +		SUBTEST(test_dag),
> +		SUBTEST(test_AB),
> +		SUBTEST(test_ABC),
> +		SUBTEST(test_AB_C),
> +		SUBTEST(test_C_AB),
> +		SUBTEST(test_chain),
> +		SUBTEST(test_ipc),
> +	};
> +
> +	return i915_subtests(tests, NULL);
> +}
> -- 
> 2.11.0
>
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