Re: [PATCH 18/24] drm/i915: unify ring irq refcounts (again)

[Daniel Vetter <daniel@ffwll.ch>]

On Fri, Jun 28, 2013 at 10:24:32AM -0700, Ben Widawsky wrote:
> On Wed, Jun 12, 2013 at 01:37:20PM +0200, Daniel Vetter wrote:
> > With the simplified locking there's no reason any more to keep the
> > refcounts seperate.
> 
> I guess my nitpick from previous patch is echoed here. The reason still
> exists, the benefit just doesn't outweigh the complexity, and I think
> we'd want separate enable_masks for pm/gt to make it worthwhile to use
> separate refcounts.

Imo it's clear enough that ring->irq_refcount is a refcount for the ring
interrupt. I've added the lost comment how it is protected by the device
irq_lock again as compensation.
-Daniel

> 
> Anyway, can you add a comment in the code about what irq_refcount does.
> with that, it's
> Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
> 
> > 
> > Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > ---
> >  drivers/gpu/drm/i915/intel_ringbuffer.c | 20 ++++++++++----------
> >  drivers/gpu/drm/i915/intel_ringbuffer.h |  5 +----
> >  2 files changed, 11 insertions(+), 14 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> > index a7c9934..b75e9d0 100644
> > --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> > @@ -819,7 +819,7 @@ gen5_ring_get_irq(struct intel_ring_buffer *ring)
> >  		return false;
> >  
> >  	spin_lock_irqsave(&dev_priv->irq_lock, flags);
> > -	if (ring->irq_refcount.gt++ == 0) {
> > +	if (ring->irq_refcount++ == 0) {
> >  		dev_priv->gt_irq_mask &= ~ring->irq_enable_mask;
> >  		I915_WRITE(GTIMR, dev_priv->gt_irq_mask);
> >  		POSTING_READ(GTIMR);
> > @@ -837,7 +837,7 @@ gen5_ring_put_irq(struct intel_ring_buffer *ring)
> >  	unsigned long flags;
> >  
> >  	spin_lock_irqsave(&dev_priv->irq_lock, flags);
> > -	if (--ring->irq_refcount.gt == 0) {
> > +	if (--ring->irq_refcount == 0) {
> >  		dev_priv->gt_irq_mask |= ring->irq_enable_mask;
> >  		I915_WRITE(GTIMR, dev_priv->gt_irq_mask);
> >  		POSTING_READ(GTIMR);
> > @@ -856,7 +856,7 @@ i9xx_ring_get_irq(struct intel_ring_buffer *ring)
> >  		return false;
> >  
> >  	spin_lock_irqsave(&dev_priv->irq_lock, flags);
> > -	if (ring->irq_refcount.gt++ == 0) {
> > +	if (ring->irq_refcount++ == 0) {
> >  		dev_priv->irq_mask &= ~ring->irq_enable_mask;
> >  		I915_WRITE(IMR, dev_priv->irq_mask);
> >  		POSTING_READ(IMR);
> > @@ -874,7 +874,7 @@ i9xx_ring_put_irq(struct intel_ring_buffer *ring)
> >  	unsigned long flags;
> >  
> >  	spin_lock_irqsave(&dev_priv->irq_lock, flags);
> > -	if (--ring->irq_refcount.gt == 0) {
> > +	if (--ring->irq_refcount == 0) {
> >  		dev_priv->irq_mask |= ring->irq_enable_mask;
> >  		I915_WRITE(IMR, dev_priv->irq_mask);
> >  		POSTING_READ(IMR);
> > @@ -893,7 +893,7 @@ i8xx_ring_get_irq(struct intel_ring_buffer *ring)
> >  		return false;
> >  
> >  	spin_lock_irqsave(&dev_priv->irq_lock, flags);
> > -	if (ring->irq_refcount.gt++ == 0) {
> > +	if (ring->irq_refcount++ == 0) {
> >  		dev_priv->irq_mask &= ~ring->irq_enable_mask;
> >  		I915_WRITE16(IMR, dev_priv->irq_mask);
> >  		POSTING_READ16(IMR);
> > @@ -911,7 +911,7 @@ i8xx_ring_put_irq(struct intel_ring_buffer *ring)
> >  	unsigned long flags;
> >  
> >  	spin_lock_irqsave(&dev_priv->irq_lock, flags);
> > -	if (--ring->irq_refcount.gt == 0) {
> > +	if (--ring->irq_refcount == 0) {
> >  		dev_priv->irq_mask |= ring->irq_enable_mask;
> >  		I915_WRITE16(IMR, dev_priv->irq_mask);
> >  		POSTING_READ16(IMR);
> > @@ -1004,7 +1004,7 @@ gen6_ring_get_irq(struct intel_ring_buffer *ring)
> >  	gen6_gt_force_wake_get(dev_priv);
> >  
> >  	spin_lock_irqsave(&dev_priv->irq_lock, flags);
> > -	if (ring->irq_refcount.gt++ == 0) {
> > +	if (ring->irq_refcount++ == 0) {
> >  		if (HAS_L3_GPU_CACHE(dev) && ring->id == RCS)
> >  			I915_WRITE_IMR(ring,
> >  				       ~(ring->irq_enable_mask |
> > @@ -1028,7 +1028,7 @@ gen6_ring_put_irq(struct intel_ring_buffer *ring)
> >  	unsigned long flags;
> >  
> >  	spin_lock_irqsave(&dev_priv->irq_lock, flags);
> > -	if (--ring->irq_refcount.gt == 0) {
> > +	if (--ring->irq_refcount == 0) {
> >  		if (HAS_L3_GPU_CACHE(dev) && ring->id == RCS)
> >  			I915_WRITE_IMR(ring,
> >  				       ~GT_RENDER_L3_PARITY_ERROR_INTERRUPT);
> > @@ -1054,7 +1054,7 @@ hsw_vebox_get_irq(struct intel_ring_buffer *ring)
> >  		return false;
> >  
> >  	spin_lock_irqsave(&dev_priv->irq_lock, flags);
> > -	if (ring->irq_refcount.pm++ == 0) {
> > +	if (ring->irq_refcount++ == 0) {
> >  		u32 pm_imr = I915_READ(GEN6_PMIMR);
> >  		I915_WRITE_IMR(ring, ~ring->irq_enable_mask);
> >  		I915_WRITE(GEN6_PMIMR, pm_imr & ~ring->irq_enable_mask);
> > @@ -1076,7 +1076,7 @@ hsw_vebox_put_irq(struct intel_ring_buffer *ring)
> >  		return;
> >  
> >  	spin_lock_irqsave(&dev_priv->irq_lock, flags);
> > -	if (--ring->irq_refcount.pm == 0) {
> > +	if (--ring->irq_refcount == 0) {
> >  		u32 pm_imr = I915_READ(GEN6_PMIMR);
> >  		I915_WRITE_IMR(ring, ~0);
> >  		I915_WRITE(GEN6_PMIMR, pm_imr | ring->irq_enable_mask);
> > diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> > index f960805..26e304c 100644
> > --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> > @@ -74,10 +74,7 @@ struct  intel_ring_buffer {
> >  	 */
> >  	u32		last_retired_head;
> >  
> > -	struct {
> > -		u32	gt; /*  protected by dev_priv->irq_lock */
> > -		u32	pm; /*  protected by dev_priv->irq_lock */
> > -	} irq_refcount;
> > +	unsigned irq_refcount;
> >  	u32		irq_enable_mask;	/* bitmask to enable ring interrupt */
> >  	u32		trace_irq_seqno;
> >  	u32		sync_seqno[I915_NUM_RINGS-1];
> > -- 
> > 1.8.1.4
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Ben Widawsky, Intel Open Source Technology Center

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch