Commit 3ef71149 authored by Chris Wilson's avatar Chris Wilson

drm/i915: Introduce i915_timeline.mutex

A simple mutex used for guarding the flow of requests in and out of the
timeline. In the short-term, it will be used only to guard the addition
of requests into the timeline, taken on alloc and released on commit so
that only one caller can construct a request into the timeline
(important as the seqno and ring pointers must be serialised). This will
be used by observers to ensure that the seqno/hwsp is stable. Later,
when we have reduced retiring to only operate on a single timeline at a
time, we can then use the mutex as the sole guard required for retiring.
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190301110547.14758-2-chris@chris-wilson.co.uk
parent b5773a36
...@@ -563,6 +563,7 @@ i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx) ...@@ -563,6 +563,7 @@ i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx)
return ERR_CAST(ce); return ERR_CAST(ce);
reserve_gt(i915); reserve_gt(i915);
mutex_lock(&ce->ring->timeline->mutex);
/* Move our oldest request to the slab-cache (if not in use!) */ /* Move our oldest request to the slab-cache (if not in use!) */
rq = list_first_entry(&ce->ring->request_list, typeof(*rq), ring_link); rq = list_first_entry(&ce->ring->request_list, typeof(*rq), ring_link);
...@@ -688,6 +689,7 @@ i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx) ...@@ -688,6 +689,7 @@ i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx)
kmem_cache_free(global.slab_requests, rq); kmem_cache_free(global.slab_requests, rq);
err_unreserve: err_unreserve:
mutex_unlock(&ce->ring->timeline->mutex);
unreserve_gt(i915); unreserve_gt(i915);
intel_context_unpin(ce); intel_context_unpin(ce);
return ERR_PTR(ret); return ERR_PTR(ret);
...@@ -880,7 +882,7 @@ void i915_request_add(struct i915_request *request) ...@@ -880,7 +882,7 @@ void i915_request_add(struct i915_request *request)
GEM_TRACE("%s fence %llx:%lld\n", GEM_TRACE("%s fence %llx:%lld\n",
engine->name, request->fence.context, request->fence.seqno); engine->name, request->fence.context, request->fence.seqno);
lockdep_assert_held(&request->i915->drm.struct_mutex); lockdep_assert_held(&request->timeline->mutex);
trace_i915_request_add(request); trace_i915_request_add(request);
/* /*
...@@ -991,6 +993,8 @@ void i915_request_add(struct i915_request *request) ...@@ -991,6 +993,8 @@ void i915_request_add(struct i915_request *request)
*/ */
if (prev && i915_request_completed(prev)) if (prev && i915_request_completed(prev))
i915_request_retire_upto(prev); i915_request_retire_upto(prev);
mutex_unlock(&request->timeline->mutex);
} }
static unsigned long local_clock_us(unsigned int *cpu) static unsigned long local_clock_us(unsigned int *cpu)
......
...@@ -162,6 +162,7 @@ int i915_timeline_init(struct drm_i915_private *i915, ...@@ -162,6 +162,7 @@ int i915_timeline_init(struct drm_i915_private *i915,
timeline->fence_context = dma_fence_context_alloc(1); timeline->fence_context = dma_fence_context_alloc(1);
spin_lock_init(&timeline->lock); spin_lock_init(&timeline->lock);
mutex_init(&timeline->mutex);
INIT_ACTIVE_REQUEST(&timeline->barrier); INIT_ACTIVE_REQUEST(&timeline->barrier);
INIT_ACTIVE_REQUEST(&timeline->last_request); INIT_ACTIVE_REQUEST(&timeline->last_request);
......
...@@ -44,6 +44,8 @@ struct i915_timeline { ...@@ -44,6 +44,8 @@ struct i915_timeline {
#define TIMELINE_CLIENT 0 /* default subclass */ #define TIMELINE_CLIENT 0 /* default subclass */
#define TIMELINE_ENGINE 1 #define TIMELINE_ENGINE 1
struct mutex mutex; /* protects the flow of requests */
unsigned int pin_count; unsigned int pin_count;
const u32 *hwsp_seqno; const u32 *hwsp_seqno;
struct i915_vma *hwsp_ggtt; struct i915_vma *hwsp_ggtt;
......
...@@ -141,14 +141,12 @@ static int igt_fence_wait(void *arg) ...@@ -141,14 +141,12 @@ static int igt_fence_wait(void *arg)
err = -ENOMEM; err = -ENOMEM;
goto out_locked; goto out_locked;
} }
mutex_unlock(&i915->drm.struct_mutex); /* safe as we are single user */
if (dma_fence_wait_timeout(&request->fence, false, T) != -ETIME) { if (dma_fence_wait_timeout(&request->fence, false, T) != -ETIME) {
pr_err("fence wait success before submit (expected timeout)!\n"); pr_err("fence wait success before submit (expected timeout)!\n");
goto out_device; goto out_locked;
} }
mutex_lock(&i915->drm.struct_mutex);
i915_request_add(request); i915_request_add(request);
mutex_unlock(&i915->drm.struct_mutex); mutex_unlock(&i915->drm.struct_mutex);
......
...@@ -14,6 +14,7 @@ void mock_timeline_init(struct i915_timeline *timeline, u64 context) ...@@ -14,6 +14,7 @@ void mock_timeline_init(struct i915_timeline *timeline, u64 context)
timeline->fence_context = context; timeline->fence_context = context;
spin_lock_init(&timeline->lock); spin_lock_init(&timeline->lock);
mutex_init(&timeline->mutex);
INIT_ACTIVE_REQUEST(&timeline->barrier); INIT_ACTIVE_REQUEST(&timeline->barrier);
INIT_ACTIVE_REQUEST(&timeline->last_request); INIT_ACTIVE_REQUEST(&timeline->last_request);
......
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