[Intel-gfx] [PATCH 2/6] drm/i915/gem: Almagamate clflushes on freeze

[Chris Wilson]

Quoting Guenter Roeck (2021-01-23 14:46:33)
> On Tue, Jan 19, 2021 at 02:49:08PM +0000, Chris Wilson wrote:
> > When flushing objects larger than the CPU cache it is preferrable to use
> > a single wbinvd() rather than overlapping clflush(). At runtime, we
> > avoid wbinvd() due to its system-wide latencies, but during
> > singlethreaded suspend, no one will observe the imposed latency and we
> > can opt for the faster wbinvd to clear all objects in a single hit.
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Reviewed-by: Matthew Auld <matthew.auld at intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_gem.c | 16 +++++-----------
> >  1 file changed, 5 insertions(+), 11 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> > index c013148835e6..d3a287bf56c5 100644
> > --- a/drivers/gpu/drm/i915/i915_gem.c
> > +++ b/drivers/gpu/drm/i915/i915_gem.c
> > @@ -1175,19 +1175,13 @@ int i915_gem_freeze_late(struct drm_i915_private *i915)
> >        * the objects as well, see i915_gem_freeze()
> >        */
> >  
> > -     wakeref = intel_runtime_pm_get(&i915->runtime_pm);
> > -
> > -     i915_gem_shrink(i915, -1UL, NULL, ~0);
> > +     with_intel_runtime_pm(&i915->runtime_pm, wakeref)
> > +             i915_gem_shrink(i915, -1UL, NULL, ~0);
> >       i915_gem_drain_freed_objects(i915);
> >  
> > -     list_for_each_entry(obj, &i915->mm.shrink_list, mm.link) {
> > -             i915_gem_object_lock(obj, NULL);
> > -             drm_WARN_ON(&i915->drm,
> > -                         i915_gem_object_set_to_cpu_domain(obj, true));
> > -             i915_gem_object_unlock(obj);
> > -     }
> > -
> > -     intel_runtime_pm_put(&i915->runtime_pm, wakeref);
> > +     wbinvd_on_all_cpus();
> 
> with CONFIG_SMP=n, this results in:
> 
> drivers/gpu/drm/i915/i915_gem.c: In function 'i915_gem_freeze_late':
> drivers/gpu/drm/i915/i915_gem.c:1182:2: error: implicit declaration of function 'wbinvd_on_all_cpus'
> 
> Other drivers calling this function include <asm/smp.h>.

I mistakenly thought this was next to i915_gem_suspend...
-Chris