Re: [Intel-gfx] [PATCH 03/21] drm/i915/gem: Set the watchdog timeout directly in intel_context_set_gem

[Jason Ekstrand <jason@jlekstrand.net>]

On Wed, Apr 28, 2021 at 10:55 AM Tvrtko Ursulin
<tvrtko.ursulin@linux.intel.com> wrote:
> On 23/04/2021 23:31, Jason Ekstrand wrote:
> > Instead of handling it like a context param, unconditionally set it when
> > intel_contexts are created.  This doesn't fix anything but does simplify
> > the code a bit.
> >
> > Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
> > ---
> >   drivers/gpu/drm/i915/gem/i915_gem_context.c   | 43 +++----------------
> >   .../gpu/drm/i915/gem/i915_gem_context_types.h |  4 --
> >   drivers/gpu/drm/i915/gt/intel_context_param.h |  3 +-
> >   3 files changed, 6 insertions(+), 44 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > index 35bcdeddfbf3f..1091cc04a242a 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > @@ -233,7 +233,11 @@ static void intel_context_set_gem(struct intel_context *ce,
> >           intel_engine_has_timeslices(ce->engine))
> >               __set_bit(CONTEXT_USE_SEMAPHORES, &ce->flags);
> >
> > -     intel_context_set_watchdog_us(ce, ctx->watchdog.timeout_us);
> > +     if (IS_ACTIVE(CONFIG_DRM_I915_REQUEST_TIMEOUT) &&
> > +         ctx->i915->params.request_timeout_ms) {
> > +             unsigned int timeout_ms = ctx->i915->params.request_timeout_ms;
> > +             intel_context_set_watchdog_us(ce, (u64)timeout_ms * 1000);
>
> Blank line between declarations and code please, or just lose the local.
>
> Otherwise looks okay. Slight change that same GEM context can now have a
> mix of different request expirations isn't interesting I think. At least
> the change goes away by the end of the series.

In order for that to happen, I think you'd have to have a race between
CREATE_CONTEXT and someone smashing the request_timeout_ms param via
sysfs.  Or am I missing something?  Given that timeouts are really
per-engine anyway, I don't think we need to care too much about that.

--Jason

> Regards,
>
> Tvrtko
>
> > +     }
> >   }
> >
> >   static void __free_engines(struct i915_gem_engines *e, unsigned int count)
> > @@ -792,41 +796,6 @@ static void __assign_timeline(struct i915_gem_context *ctx,
> >       context_apply_all(ctx, __apply_timeline, timeline);
> >   }
> >
> > -static int __apply_watchdog(struct intel_context *ce, void *timeout_us)
> > -{
> > -     return intel_context_set_watchdog_us(ce, (uintptr_t)timeout_us);
> > -}
> > -
> > -static int
> > -__set_watchdog(struct i915_gem_context *ctx, unsigned long timeout_us)
> > -{
> > -     int ret;
> > -
> > -     ret = context_apply_all(ctx, __apply_watchdog,
> > -                             (void *)(uintptr_t)timeout_us);
> > -     if (!ret)
> > -             ctx->watchdog.timeout_us = timeout_us;
> > -
> > -     return ret;
> > -}
> > -
> > -static void __set_default_fence_expiry(struct i915_gem_context *ctx)
> > -{
> > -     struct drm_i915_private *i915 = ctx->i915;
> > -     int ret;
> > -
> > -     if (!IS_ACTIVE(CONFIG_DRM_I915_REQUEST_TIMEOUT) ||
> > -         !i915->params.request_timeout_ms)
> > -             return;
> > -
> > -     /* Default expiry for user fences. */
> > -     ret = __set_watchdog(ctx, i915->params.request_timeout_ms * 1000);
> > -     if (ret)
> > -             drm_notice(&i915->drm,
> > -                        "Failed to configure default fence expiry! (%d)",
> > -                        ret);
> > -}
> > -
> >   static struct i915_gem_context *
> >   i915_gem_create_context(struct drm_i915_private *i915, unsigned int flags)
> >   {
> > @@ -871,8 +840,6 @@ i915_gem_create_context(struct drm_i915_private *i915, unsigned int flags)
> >               intel_timeline_put(timeline);
> >       }
> >
> > -     __set_default_fence_expiry(ctx);
> > -
> >       trace_i915_context_create(ctx);
> >
> >       return ctx;
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
> > index 5ae71ec936f7c..676592e27e7d2 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h
> > @@ -153,10 +153,6 @@ struct i915_gem_context {
> >        */
> >       atomic_t active_count;
> >
> > -     struct {
> > -             u64 timeout_us;
> > -     } watchdog;
> > -
> >       /**
> >        * @hang_timestamp: The last time(s) this context caused a GPU hang
> >        */
> > diff --git a/drivers/gpu/drm/i915/gt/intel_context_param.h b/drivers/gpu/drm/i915/gt/intel_context_param.h
> > index dffedd983693d..0c69cb42d075c 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_context_param.h
> > +++ b/drivers/gpu/drm/i915/gt/intel_context_param.h
> > @@ -10,11 +10,10 @@
> >
> >   #include "intel_context.h"
> >
> > -static inline int
> > +static inline void
> >   intel_context_set_watchdog_us(struct intel_context *ce, u64 timeout_us)
> >   {
> >       ce->watchdog.timeout_us = timeout_us;
> > -     return 0;
> >   }
> >
> >   #endif /* INTEL_CONTEXT_PARAM_H */
> >
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