Re: [PATCH 18/27] drm/i915/gem: Optionally set SSEU in intel_context_set_gem

[Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>]

On 04/05/2021 20:00, Daniel Vetter wrote:
> On Mon, May 03, 2021 at 10:57:39AM -0500, Jason Ekstrand wrote:
> > For now this is a no-op because everyone passes in a null SSEU but it
> > lets us get some of the error handling and selftest refactoring plumbed
> > through.
> >
> > Signed-off-by: Jason Ekstrand <jason@xxxxxxxxxxxxxx>
>
> it is a bit icky that intel_context_set_gem also sets the sseu, feels a
> bit like a layering violation, but welp I couldn't come up with a better
> idea either.
>
> Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>

It is actually quite horrible. As you say it breaks separation of duties 
and open codes stuff all over the place without transferring over the 
commentary about why.

Regards,

Tvrtko

> > ---
> >   drivers/gpu/drm/i915/gem/i915_gem_context.c   | 41 +++++++++++++++----
> >   .../gpu/drm/i915/gem/selftests/mock_context.c |  6 ++-
> >   2 files changed, 36 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > index ce729e640bbf7..6dd50d669c5b9 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > @@ -320,9 +320,12 @@ context_get_vm_rcu(struct i915_gem_context *ctx)
> >   	} while (1);
> >   }
> >   
> > -static void intel_context_set_gem(struct intel_context *ce,
> > -				  struct i915_gem_context *ctx)
> > +static int intel_context_set_gem(struct intel_context *ce,
> > +				 struct i915_gem_context *ctx,
> > +				 struct intel_sseu sseu)
> >   {
> > +	int ret = 0;
> > +
> >   	GEM_BUG_ON(rcu_access_pointer(ce->gem_context));
> >   	RCU_INIT_POINTER(ce->gem_context, ctx);
> >   
> > @@ -349,6 +352,12 @@ static void intel_context_set_gem(struct intel_context *ce,
> >   
> >   		intel_context_set_watchdog_us(ce, (u64)timeout_ms * 1000);
> >   	}
> > +
> > +	/* A valid SSEU has no zero fields */
> > +	if (sseu.slice_mask && !WARN_ON(ce->engine->class != RENDER_CLASS))
> > +		ret = intel_context_reconfigure_sseu(ce, sseu);
> > +
> > +	return ret;
> >   }
> >   
> >   static void __free_engines(struct i915_gem_engines *e, unsigned int count)
> > @@ -416,7 +425,8 @@ static struct i915_gem_engines *alloc_engines(unsigned int count)
> >   	return e;
> >   }
> >   
> > -static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx)
> > +static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx,
> > +						struct intel_sseu rcs_sseu)
> >   {
> >   	const struct intel_gt *gt = &ctx->i915->gt;
> >   	struct intel_engine_cs *engine;
> > @@ -429,6 +439,8 @@ static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx)
> >   
> >   	for_each_engine(engine, gt, id) {
> >   		struct intel_context *ce;
> > +		struct intel_sseu sseu = {};
> > +		int ret;
> >   
> >   		if (engine->legacy_idx == INVALID_ENGINE)
> >   			continue;
> > @@ -442,10 +454,18 @@ static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx)
> >   			goto free_engines;
> >   		}
> >   
> > -		intel_context_set_gem(ce, ctx);
> > -
> >   		e->engines[engine->legacy_idx] = ce;
> >   		e->num_engines = max(e->num_engines, engine->legacy_idx + 1);
> > +
> > +		if (engine->class == RENDER_CLASS)
> > +			sseu = rcs_sseu;
> > +
> > +		ret = intel_context_set_gem(ce, ctx, sseu);
> > +		if (ret) {
> > +			err = ERR_PTR(ret);
> > +			goto free_engines;
> > +		}
> > +
> >   	}
> >   
> >   	return e;
> > @@ -759,6 +779,7 @@ __create_context(struct drm_i915_private *i915,
> >   {
> >   	struct i915_gem_context *ctx;
> >   	struct i915_gem_engines *e;
> > +	struct intel_sseu null_sseu = {};
> >   	int err;
> >   	int i;
> >   
> > @@ -776,7 +797,7 @@ __create_context(struct drm_i915_private *i915,
> >   	INIT_LIST_HEAD(&ctx->stale.engines);
> >   
> >   	mutex_init(&ctx->engines_mutex);
> > -	e = default_engines(ctx);
> > +	e = default_engines(ctx, null_sseu);
> >   	if (IS_ERR(e)) {
> >   		err = PTR_ERR(e);
> >   		goto err_free;
> > @@ -1544,6 +1565,7 @@ set_engines__load_balance(struct i915_user_extension __user *base, void *data)
> >   	struct intel_engine_cs *stack[16];
> >   	struct intel_engine_cs **siblings;
> >   	struct intel_context *ce;
> > +	struct intel_sseu null_sseu = {};
> >   	u16 num_siblings, idx;
> >   	unsigned int n;
> >   	int err;
> > @@ -1616,7 +1638,7 @@ set_engines__load_balance(struct i915_user_extension __user *base, void *data)
> >   		goto out_siblings;
> >   	}
> >   
> > -	intel_context_set_gem(ce, set->ctx);
> > +	intel_context_set_gem(ce, set->ctx, null_sseu);
> >   
> >   	if (cmpxchg(&set->engines->engines[idx], NULL, ce)) {
> >   		intel_context_put(ce);
> > @@ -1724,6 +1746,7 @@ set_engines(struct i915_gem_context *ctx,
> >   	struct drm_i915_private *i915 = ctx->i915;
> >   	struct i915_context_param_engines __user *user =
> >   		u64_to_user_ptr(args->value);
> > +	struct intel_sseu null_sseu = {};
> >   	struct set_engines set = { .ctx = ctx };
> >   	unsigned int num_engines, n;
> >   	u64 extensions;
> > @@ -1733,7 +1756,7 @@ set_engines(struct i915_gem_context *ctx,
> >   		if (!i915_gem_context_user_engines(ctx))
> >   			return 0;
> >   
> > -		set.engines = default_engines(ctx);
> > +		set.engines = default_engines(ctx, null_sseu);
> >   		if (IS_ERR(set.engines))
> >   			return PTR_ERR(set.engines);
> >   
> > @@ -1790,7 +1813,7 @@ set_engines(struct i915_gem_context *ctx,
> >   			return PTR_ERR(ce);
> >   		}
> >   
> > -		intel_context_set_gem(ce, ctx);
> > +		intel_context_set_gem(ce, ctx, null_sseu);
> >   
> >   		set.engines->engines[n] = ce;
> >   	}
> > diff --git a/drivers/gpu/drm/i915/gem/selftests/mock_context.c b/drivers/gpu/drm/i915/gem/selftests/mock_context.c
> > index e0f512ef7f3c6..cbeefd060e97b 100644
> > --- a/drivers/gpu/drm/i915/gem/selftests/mock_context.c
> > +++ b/drivers/gpu/drm/i915/gem/selftests/mock_context.c
> > @@ -14,6 +14,7 @@ mock_context(struct drm_i915_private *i915,
> >   {
> >   	struct i915_gem_context *ctx;
> >   	struct i915_gem_engines *e;
> > +	struct intel_sseu null_sseu = {};
> >   
> >   	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
> >   	if (!ctx)
> > @@ -31,7 +32,7 @@ mock_context(struct drm_i915_private *i915,
> >   	i915_gem_context_set_persistence(ctx);
> >   
> >   	mutex_init(&ctx->engines_mutex);
> > -	e = default_engines(ctx);
> > +	e = default_engines(ctx, null_sseu);
> >   	if (IS_ERR(e))
> >   		goto err_free;
> >   	RCU_INIT_POINTER(ctx->engines, e);
> > @@ -112,6 +113,7 @@ live_context_for_engine(struct intel_engine_cs *engine, struct file *file)
> >   {
> >   	struct i915_gem_engines *engines;
> >   	struct i915_gem_context *ctx;
> > +	struct intel_sseu null_sseu = {};
> >   	struct intel_context *ce;
> >   
> >   	engines = alloc_engines(1);
> > @@ -130,7 +132,7 @@ live_context_for_engine(struct intel_engine_cs *engine, struct file *file)
> >   		return ERR_CAST(ce);
> >   	}
> >   
> > -	intel_context_set_gem(ce, ctx);
> > +	intel_context_set_gem(ce, ctx, null_sseu);
> >   	engines->engines[0] = ce;
> >   	engines->num_engines = 1;
> >   
> > --
> > 2.31.1
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
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