[Intel-gfx] [PATCH] drm/i915: Push irq_shift from gen8_cs_irq_handler() to caller

[Daniele Ceraolo Spurio]

On 08/03/18 16:16, Chris Wilson wrote:
> Originally we were inlining gen8_cs_irq_handler() and so expected the
> compiler to constant-fold away the irq_shift (so we had hardcoded it as
> opposed to use engine->irq_shift). However, we dropped the inline given
> the proliferation of gen8_cs_irq_handler()s. If we pull the shifting
> of the iir into the caller, we can shrink the code still further:
> 
> add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-34 (-34)
> Function                                     old     new   delta
> gen8_cs_irq_handler                          123     118      -5
> gen8_gt_irq_handler                          261     248     -13
> gen11_irq_handler                            722     706     -16
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_irq.c | 18 +++++++++---------
>   1 file changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index babf81cf668b..84c0043e1637 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -1399,19 +1399,19 @@ static void snb_gt_irq_handler(struct drm_i915_private *dev_priv,
>   }
>   
>   static void
> -gen8_cs_irq_handler(struct intel_engine_cs *engine, u32 iir, int test_shift)
> +gen8_cs_irq_handler(struct intel_engine_cs *engine, u32 iir)
>   {
>   	struct intel_engine_execlists * const execlists = &engine->execlists;
>   	bool tasklet = false;
>   
> -	if (iir & (GT_CONTEXT_SWITCH_INTERRUPT << test_shift)) {
> +	if (iir & GT_CONTEXT_SWITCH_INTERRUPT) {
>   		if (READ_ONCE(engine->execlists.active)) {
>   			__set_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted);
>   			tasklet = true;
>   		}
>   	}
>   
> -	if (iir & (GT_RENDER_USER_INTERRUPT << test_shift)) {
> +	if (iir & GT_RENDER_USER_INTERRUPT) {
>   		notify_ring(engine);
>   		tasklet |= USES_GUC_SUBMISSION(engine->i915);
>   	}
> @@ -1466,21 +1466,21 @@ static void gen8_gt_irq_handler(struct drm_i915_private *i915,
>   {
>   	if (master_ctl & (GEN8_GT_RCS_IRQ | GEN8_GT_BCS_IRQ)) {
>   		gen8_cs_irq_handler(i915->engine[RCS],
> -				    gt_iir[0], GEN8_RCS_IRQ_SHIFT);
> +				    gt_iir[0] >> GEN8_RCS_IRQ_SHIFT);
>   		gen8_cs_irq_handler(i915->engine[BCS],
> -				    gt_iir[0], GEN8_BCS_IRQ_SHIFT);
> +				    gt_iir[0] >> GEN8_BCS_IRQ_SHIFT);
>   	}
>   
>   	if (master_ctl & (GEN8_GT_VCS1_IRQ | GEN8_GT_VCS2_IRQ)) {
>   		gen8_cs_irq_handler(i915->engine[VCS],
> -				    gt_iir[1], GEN8_VCS1_IRQ_SHIFT);
> +				    gt_iir[1] >> GEN8_VCS1_IRQ_SHIFT);
>   		gen8_cs_irq_handler(i915->engine[VCS2],
> -				    gt_iir[1], GEN8_VCS2_IRQ_SHIFT);
> +				    gt_iir[1] >> GEN8_VCS2_IRQ_SHIFT);
>   	}
>   
>   	if (master_ctl & GEN8_GT_VECS_IRQ) {
>   		gen8_cs_irq_handler(i915->engine[VECS],
> -				    gt_iir[3], GEN8_VECS_IRQ_SHIFT);
> +				    gt_iir[3] >> GEN8_VECS_IRQ_SHIFT);
>   	}
>   
>   	if (master_ctl & (GEN8_GT_PM_IRQ | GEN8_GT_GUC_IRQ)) {
> @@ -2765,7 +2765,7 @@ static void __fini_wedge(struct wedge_me *w)
>   static __always_inline void
>   gen11_cs_irq_handler(struct intel_engine_cs * const engine, const u32 iir)
>   {
> -	gen8_cs_irq_handler(engine, iir, 0);
> +	gen8_cs_irq_handler(engine, iir);

Could potentially drop gen11_cs_irq_handler entirely since now it is 
identical to gen8_cs_irq_handler, but either way:

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>

Daniele

>   }
>   
>   static void
>