[PATCH 02/27] drm/i915: Stop storing the ring size in the ring pointer

Jason Ekstrand jason at jlekstrand.net
Fri May 14 18:06:10 UTC 2021


On Tue, May 4, 2021 at 3:47 AM Daniel Vetter <daniel at ffwll.ch> wrote:
>
> On Mon, May 03, 2021 at 10:57:23AM -0500, Jason Ekstrand wrote:
> > Previously, we were storing the ring size in the ring pointer before it
> > was actually allocated.  We would then guard setting the ring size on
> > checking for CONTEXT_ALLOC_BIT.  This is error-prone at best and really
> > only saves us a few bytes on something that already burns at least 4K.
> > Instead, this patch adds a new ring_size field and makes everything use
> > that.
> >
> > Signed-off-by: Jason Ekstrand <jason at jlekstrand.net>
> > ---
> >  drivers/gpu/drm/i915/gem/i915_gem_context.c   | 3 +--
> >  drivers/gpu/drm/i915/gt/intel_context.c       | 3 ++-
> >  drivers/gpu/drm/i915/gt/intel_context.h       | 5 -----
> >  drivers/gpu/drm/i915/gt/intel_context_types.h | 1 +
> >  drivers/gpu/drm/i915/gt/intel_lrc.c           | 2 +-
> >  drivers/gpu/drm/i915/gt/selftest_execlists.c  | 2 +-
> >  drivers/gpu/drm/i915/gt/selftest_mocs.c       | 2 +-
> >  drivers/gpu/drm/i915/gt/selftest_timeline.c   | 2 +-
> >  drivers/gpu/drm/i915/gvt/scheduler.c          | 7 ++-----
> >  9 files changed, 10 insertions(+), 17 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > index e52b85b8f923d..2ba4c7e4011b4 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > @@ -211,8 +211,7 @@ static void intel_context_set_gem(struct intel_context *ce,
> >       GEM_BUG_ON(rcu_access_pointer(ce->gem_context));
> >       RCU_INIT_POINTER(ce->gem_context, ctx);
> >
> > -     if (!test_bit(CONTEXT_ALLOC_BIT, &ce->flags))
> > -             ce->ring = __intel_context_ring_size(SZ_16K);
> > +     ce->ring_size = SZ_16K;
> >
> >       if (rcu_access_pointer(ctx->vm)) {
> >               struct i915_address_space *vm;
> > diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
> > index 17cf2640b082b..342fa7daa08b5 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_context.c
> > +++ b/drivers/gpu/drm/i915/gt/intel_context.c
> > @@ -372,7 +372,8 @@ intel_context_init(struct intel_context *ce, struct intel_engine_cs *engine)
> >       ce->engine = engine;
> >       ce->ops = engine->cops;
> >       ce->sseu = engine->sseu;
> > -     ce->ring = __intel_context_ring_size(SZ_4K);
> > +     ce->ring = NULL;
> > +     ce->ring_size = SZ_4K;
> >
> >       ewma_runtime_init(&ce->runtime.avg);
> >
> > diff --git a/drivers/gpu/drm/i915/gt/intel_context.h b/drivers/gpu/drm/i915/gt/intel_context.h
> > index f83a73a2b39fc..b10cbe8fee992 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_context.h
> > +++ b/drivers/gpu/drm/i915/gt/intel_context.h
> > @@ -175,11 +175,6 @@ int intel_context_prepare_remote_request(struct intel_context *ce,
> >
> >  struct i915_request *intel_context_create_request(struct intel_context *ce);
> >
> > -static inline struct intel_ring *__intel_context_ring_size(u64 sz)
> > -{
> > -     return u64_to_ptr(struct intel_ring, sz);
> > -}
> > -
> >  static inline bool intel_context_is_barrier(const struct intel_context *ce)
> >  {
> >       return test_bit(CONTEXT_BARRIER_BIT, &ce->flags);
> > diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
> > index ed8c447a7346b..90026c1771055 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_context_types.h
> > +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
> > @@ -82,6 +82,7 @@ struct intel_context {
> >       spinlock_t signal_lock; /* protects signals, the list of requests */
> >
> >       struct i915_vma *state;
> > +     u32 ring_size;
> >       struct intel_ring *ring;
> >       struct intel_timeline *timeline;
> >
> > diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
> > index e86897cde9846..63193c80fb117 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
> > +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
> > @@ -845,7 +845,7 @@ int lrc_alloc(struct intel_context *ce, struct intel_engine_cs *engine)
> >       if (IS_ERR(vma))
> >               return PTR_ERR(vma);
> >
> > -     ring = intel_engine_create_ring(engine, (unsigned long)ce->ring);
> > +     ring = intel_engine_create_ring(engine, ce->ring_size);
> >       if (IS_ERR(ring)) {
> >               err = PTR_ERR(ring);
> >               goto err_vma;
> > diff --git a/drivers/gpu/drm/i915/gt/selftest_execlists.c b/drivers/gpu/drm/i915/gt/selftest_execlists.c
> > index 1081cd36a2bd3..01d9896dd4844 100644
> > --- a/drivers/gpu/drm/i915/gt/selftest_execlists.c
> > +++ b/drivers/gpu/drm/i915/gt/selftest_execlists.c
> > @@ -2793,7 +2793,7 @@ static int __live_preempt_ring(struct intel_engine_cs *engine,
> >                       goto err_ce;
> >               }
> >
> > -             tmp->ring = __intel_context_ring_size(ring_sz);
> > +             tmp->ring_size = ring_sz;
> >
> >               err = intel_context_pin(tmp);
> >               if (err) {
> > diff --git a/drivers/gpu/drm/i915/gt/selftest_mocs.c b/drivers/gpu/drm/i915/gt/selftest_mocs.c
> > index e55a887d11e2b..f343fa5fd986f 100644
> > --- a/drivers/gpu/drm/i915/gt/selftest_mocs.c
> > +++ b/drivers/gpu/drm/i915/gt/selftest_mocs.c
> > @@ -28,7 +28,7 @@ static struct intel_context *mocs_context_create(struct intel_engine_cs *engine)
> >               return ce;
> >
> >       /* We build large requests to read the registers from the ring */
> > -     ce->ring = __intel_context_ring_size(SZ_16K);
> > +     ce->ring_size = SZ_16K;
> >
> >       return ce;
> >  }
> > diff --git a/drivers/gpu/drm/i915/gt/selftest_timeline.c b/drivers/gpu/drm/i915/gt/selftest_timeline.c
> > index 9adbd9d147bea..7eedecfb86e59 100644
> > --- a/drivers/gpu/drm/i915/gt/selftest_timeline.c
> > +++ b/drivers/gpu/drm/i915/gt/selftest_timeline.c
> > @@ -874,7 +874,7 @@ static int create_watcher(struct hwsp_watcher *w,
> >       if (IS_ERR(ce))
> >               return PTR_ERR(ce);
> >
> > -     ce->ring = __intel_context_ring_size(ringsz);
> > +     ce->ring_size = ringsz;
> >       w->rq = intel_context_create_request(ce);
> >       intel_context_put(ce);
> >       if (IS_ERR(w->rq))
> > diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
> > index fc735692f21fb..99bc9fed6fbb6 100644
> > --- a/drivers/gpu/drm/i915/gvt/scheduler.c
> > +++ b/drivers/gpu/drm/i915/gvt/scheduler.c
> > @@ -1409,11 +1409,8 @@ int intel_vgpu_setup_submission(struct intel_vgpu *vgpu)
> >               intel_context_set_single_submission(ce);
> >
> >               /* Max ring buffer size */
> > -             if (!intel_uc_wants_guc_submission(&engine->gt->uc)) {
> > -                     const unsigned int ring_size = 512 * SZ_4K;
> > -
> > -                     ce->ring = __intel_context_ring_size(ring_size);
> > -             }
> > +             if (!intel_uc_wants_guc_submission(&engine->gt->uc))
> > +                     ce->ring_size = 512 * SZ_4K;
>
> A rather funny way of saying SZ_2M. Maybe fix that if you feel like. W/ or
> w/o that:

Done.

> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
>
> >
> >               s->shadow[i] = ce;
> >       }
> > --
> > 2.31.1
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch


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