From 18bb2bccb5492fb5c36908191b8af77e54c58814 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 14 Jan 2019 21:04:01 +0000 Subject: [PATCH] drm/i915: Serialise concurrent calls to i915_gem_set_wedged() Make i915_gem_set_wedged() and i915_gem_unset_wedged() behaviour more consistent if called concurrently, and only do the wedging and reporting once, curtailing any possible race where we start unwedging in the middle of a wedge. Signed-off-by: Chris Wilson Cc: Mika Kuoppala Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20190114210408.4561-2-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_gem.c | 32 ++++++++++++++----- drivers/gpu/drm/i915/i915_gpu_error.h | 4 ++- .../gpu/drm/i915/selftests/mock_gem_device.c | 1 + 3 files changed, 28 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 565b2fa1607d..5c6089777fde 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -3187,10 +3187,15 @@ static void nop_submit_request(struct i915_request *request) void i915_gem_set_wedged(struct drm_i915_private *i915) { + struct i915_gpu_error *error = &i915->gpu_error; struct intel_engine_cs *engine; enum intel_engine_id id; - GEM_TRACE("start\n"); + mutex_lock(&error->wedge_mutex); + if (test_bit(I915_WEDGED, &error->flags)) { + mutex_unlock(&error->wedge_mutex); + return; + } if (GEM_SHOW_DEBUG() && !intel_engines_are_idle(i915)) { struct drm_printer p = drm_debug_printer(__func__); @@ -3199,8 +3204,7 @@ void i915_gem_set_wedged(struct drm_i915_private *i915) intel_engine_dump(engine, &p, "%s\n", engine->name); } - if (test_and_set_bit(I915_WEDGED, &i915->gpu_error.flags)) - goto out; + GEM_TRACE("start\n"); /* * First, stop submission to hw, but do not yet complete requests by @@ -3236,23 +3240,31 @@ void i915_gem_set_wedged(struct drm_i915_private *i915) intel_engine_wakeup(engine); } -out: + smp_mb__before_atomic(); + set_bit(I915_WEDGED, &error->flags); + GEM_TRACE("end\n"); + mutex_unlock(&error->wedge_mutex); - wake_up_all(&i915->gpu_error.reset_queue); + wake_up_all(&error->reset_queue); } bool i915_gem_unset_wedged(struct drm_i915_private *i915) { + struct i915_gpu_error *error = &i915->gpu_error; struct i915_timeline *tl; + bool ret = false; lockdep_assert_held(&i915->drm.struct_mutex); - if (!test_bit(I915_WEDGED, &i915->gpu_error.flags)) + + if (!test_bit(I915_WEDGED, &error->flags)) return true; if (!i915->gt.scratch) /* Never full initialised, recovery impossible */ return false; + mutex_lock(&error->wedge_mutex); + GEM_TRACE("start\n"); /* @@ -3286,7 +3298,7 @@ bool i915_gem_unset_wedged(struct drm_i915_private *i915) */ if (dma_fence_default_wait(&rq->fence, true, MAX_SCHEDULE_TIMEOUT) < 0) - return false; + goto unlock; } i915_retire_requests(i915); GEM_BUG_ON(i915->gt.active_requests); @@ -3309,8 +3321,11 @@ bool i915_gem_unset_wedged(struct drm_i915_private *i915) smp_mb__before_atomic(); /* complete takeover before enabling execbuf */ clear_bit(I915_WEDGED, &i915->gpu_error.flags); + ret = true; +unlock: + mutex_unlock(&i915->gpu_error.wedge_mutex); - return true; + return ret; } static void @@ -5706,6 +5721,7 @@ int i915_gem_init_early(struct drm_i915_private *dev_priv) i915_gem_idle_work_handler); init_waitqueue_head(&dev_priv->gpu_error.wait_queue); init_waitqueue_head(&dev_priv->gpu_error.reset_queue); + mutex_init(&dev_priv->gpu_error.wedge_mutex); atomic_set(&dev_priv->mm.bsd_engine_dispatch_index, 0); diff --git a/drivers/gpu/drm/i915/i915_gpu_error.h b/drivers/gpu/drm/i915/i915_gpu_error.h index 6d9f45468ac1..604291f7762d 100644 --- a/drivers/gpu/drm/i915/i915_gpu_error.h +++ b/drivers/gpu/drm/i915/i915_gpu_error.h @@ -271,8 +271,8 @@ struct i915_gpu_error { #define I915_RESET_BACKOFF 0 #define I915_RESET_HANDOFF 1 #define I915_RESET_MODESET 2 +#define I915_RESET_ENGINE 3 #define I915_WEDGED (BITS_PER_LONG - 1) -#define I915_RESET_ENGINE (I915_WEDGED - I915_NUM_ENGINES) /** Number of times an engine has been reset */ u32 reset_engine_count[I915_NUM_ENGINES]; @@ -283,6 +283,8 @@ struct i915_gpu_error { /** Reason for the current *global* reset */ const char *reason; + struct mutex wedge_mutex; /* serialises wedging/unwedging */ + /** * Waitqueue to signal when a hang is detected. Used to for waiters * to release the struct_mutex for the reset to procede. diff --git a/drivers/gpu/drm/i915/selftests/mock_gem_device.c b/drivers/gpu/drm/i915/selftests/mock_gem_device.c index 082809569681..3cda66292e76 100644 --- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c +++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c @@ -188,6 +188,7 @@ struct drm_i915_private *mock_gem_device(void) init_waitqueue_head(&i915->gpu_error.wait_queue); init_waitqueue_head(&i915->gpu_error.reset_queue); + mutex_init(&i915->gpu_error.wedge_mutex); i915->wq = alloc_ordered_workqueue("mock", 0); if (!i915->wq) -- 2.30.2