This essentially reverts
commit 89ff76bf9b3b0b86e6bbe344bd6378d8661303fc Author: Chris Wilson chris@chris-wilson.co.uk Date: Thu Apr 2 13:42:18 2020 +0100
drm/i915/gem: Utilize rcu iteration of context engines
Note that the other use of __context_engines_await have disappeard in the following commits:
ccbc1b97948a ("drm/i915/gem: Don't allow changing the VM on running contexts (v4)") c7a71fc8ee04 ("drm/i915: Drop getparam support for I915_CONTEXT_PARAM_ENGINES") 4a766ae40ec8 ("drm/i915: Drop the CONTEXT_CLONE API (v2)")
None of these have any business to optimize their engine lookup with rcu, unless extremely convincing benchmark data and a solid analysis why we can't make that workload (whatever it is that does) faster with a proper design fix.
Also since there's only one caller of context_apply_all left and it's really just a loop, inline it and then inline the lopp body too. This is how all other callers that take the engine lock loop over engines, it's much simpler.
Signed-off-by: Daniel Vetter daniel.vetter@intel.com Cc: Chris Wilson chris@chris-wilson.co.uk Cc: Mika Kuoppala mika.kuoppala@linux.intel.com Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Jason Ekstrand jason@jlekstrand.net Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Cc: Matthew Brost matthew.brost@intel.com --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 72 ++++----------------- 1 file changed, 14 insertions(+), 58 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index dbaeb924a437..fd169cf2f75a 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -1284,49 +1284,6 @@ static int __context_set_persistence(struct i915_gem_context *ctx, bool state) return 0; }
-static inline struct i915_gem_engines * -__context_engines_await(const struct i915_gem_context *ctx, - bool *user_engines) -{ - struct i915_gem_engines *engines; - - rcu_read_lock(); - do { - engines = rcu_dereference(ctx->engines); - GEM_BUG_ON(!engines); - - if (user_engines) - *user_engines = i915_gem_context_user_engines(ctx); - - /* successful await => strong mb */ - if (unlikely(!i915_sw_fence_await(&engines->fence))) - continue; - - if (likely(engines == rcu_access_pointer(ctx->engines))) - break; - - i915_sw_fence_complete(&engines->fence); - } while (1); - rcu_read_unlock(); - - return engines; -} - -static void -context_apply_all(struct i915_gem_context *ctx, - void (*fn)(struct intel_context *ce, void *data), - void *data) -{ - struct i915_gem_engines_iter it; - struct i915_gem_engines *e; - struct intel_context *ce; - - e = __context_engines_await(ctx, NULL); - for_each_gem_engine(ce, e, it) - fn(ce, data); - i915_sw_fence_complete(&e->fence); -} - static struct i915_gem_context * i915_gem_create_context(struct drm_i915_private *i915, const struct i915_gem_proto_context *pc) @@ -1776,23 +1733,11 @@ set_persistence(struct i915_gem_context *ctx, return __context_set_persistence(ctx, args->value); }
-static void __apply_priority(struct intel_context *ce, void *arg) -{ - struct i915_gem_context *ctx = arg; - - if (!intel_engine_has_timeslices(ce->engine)) - return; - - if (ctx->sched.priority >= I915_PRIORITY_NORMAL && - intel_engine_has_semaphores(ce->engine)) - intel_context_set_use_semaphores(ce); - else - intel_context_clear_use_semaphores(ce); -} - static int set_priority(struct i915_gem_context *ctx, const struct drm_i915_gem_context_param *args) { + struct i915_gem_engines_iter it; + struct intel_context *ce; int err;
err = validate_priority(ctx->i915, args); @@ -1800,7 +1745,18 @@ static int set_priority(struct i915_gem_context *ctx, return err;
ctx->sched.priority = args->value; - context_apply_all(ctx, __apply_priority, ctx); + + for_each_gem_engine(ce, i915_gem_context_lock_engines(ctx), it) { + if (!intel_engine_has_timeslices(ce->engine)) + continue; + + if (ctx->sched.priority >= I915_PRIORITY_NORMAL && + intel_engine_has_semaphores(ce->engine)) + intel_context_set_use_semaphores(ce); + else + intel_context_clear_use_semaphores(ce); + } + i915_gem_context_unlock_engines(ctx);
return 0; }