If we want to percolate information back from the HW, up through the GEM
context, we need to wait until the intel_context is scheduled out for
the last time. This is handled by the retirement of the intel_context's
barrier, i.e. by listening to the pulse after the notional unpin.
To accommodate this, we need to be able to flush the i915_active's
barriers before awaiting on them. However, this also requires us to
ensure the context is unpinned *before* the barrier request can be
signaled, so mark it as a sentinel.
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursu...@intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_context.c | 17 ++++------
drivers/gpu/drm/i915/i915_active.c | 37 ++++++++++++++++-----
drivers/gpu/drm/i915/i915_active.h | 3 +-
3 files changed, 37 insertions(+), 20 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c
b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index c0e476fcd1fa..05fed8797d37 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -570,23 +570,20 @@ static void engines_idle_release(struct i915_gem_context
*ctx,
engines->ctx = i915_gem_context_get(ctx);
for_each_gem_engine(ce, engines, it) {
- struct dma_fence *fence;
- int err = 0;
+ int err;
/* serialises with execbuf */
RCU_INIT_POINTER(ce->gem_context, NULL);
if (!intel_context_pin_if_active(ce))
continue;
- fence = i915_active_fence_get(&ce->timeline->last_request);
- if (fence) {
- err = i915_sw_fence_await_dma_fence(&engines->fence,
- fence, 0,
- GFP_KERNEL);
- dma_fence_put(fence);
- }
+ /* Wait until context is finally scheduled out and retired */
+ err = i915_sw_fence_await_active(&engines->fence,
+ &ce->active,
+ I915_ACTIVE_AWAIT_ACTIVE |
+ I915_ACTIVE_AWAIT_BARRIER);
intel_context_unpin(ce);
- if (err < 0)
+ if (err)
goto kill;
}
diff --git a/drivers/gpu/drm/i915/i915_active.c
b/drivers/gpu/drm/i915/i915_active.c
index c4048628188a..da7d35f66dd0 100644
--- a/drivers/gpu/drm/i915/i915_active.c
+++ b/drivers/gpu/drm/i915/i915_active.c
@@ -518,19 +518,18 @@ int i915_active_wait(struct i915_active *ref)
return 0;
}
-static int __await_active(struct i915_active_fence *active,
- int (*fn)(void *arg, struct dma_fence *fence),
- void *arg)
+static int __await_fence(struct i915_active_fence *active,
+ int (*fn)(void *arg, struct dma_fence *fence),
+ void *arg)
{
struct dma_fence *fence;
+ int err;
- if (is_barrier(active)) /* XXX flush the barrier? */
+ if (is_barrier(active))
return 0;
fence = i915_active_fence_get(active);
if (fence) {
- int err;
-
err = fn(arg, fence);
dma_fence_put(fence);
if (err < 0)
@@ -540,6 +539,22 @@ static int __await_active(struct i915_active_fence *active,
return 0;
}
+static int __await_active(struct active_node *it,
+ unsigned int flags,
+ int (*fn)(void *arg, struct dma_fence *fence),
+ void *arg)
+{
+ int err;
+
+ if (flags & I915_ACTIVE_AWAIT_BARRIER) {
+ err = flush_barrier(it);
+ if (err)
+ return err;
+ }
+
+ return __await_fence(&it->base, fn, arg);
+}
+
static int await_active(struct i915_active *ref,
unsigned int flags,
int (*fn)(void *arg, struct dma_fence *fence),
@@ -549,16 +564,17 @@ static int await_active(struct i915_active *ref,
/* We must always wait for the exclusive fence! */
if (rcu_access_pointer(ref->excl.fence)) {
- err = __await_active(&ref->excl, fn, arg);
+ err = __await_fence(&ref->excl, fn, arg);
if (err)
return err;
}
- if (flags & I915_ACTIVE_AWAIT_ALL && i915_active_acquire_if_busy(ref)) {
+ if (flags & I915_ACTIVE_AWAIT_ACTIVE &&
+ i915_active_acquire_if_busy(ref)) {
struct active_node *it, *n;
rbtree_postorder_for_each_entry_safe(it, n, &ref->tree, node) {
- err = __await_active(&it->base, fn, arg);
+ err = __await_active(it, flags, fn, arg);
if (err)
break;
}
@@ -852,6 +868,9 @@ void i915_request_add_active_barriers(struct i915_request
*rq)
list_add_tail((struct list_head *)node, &rq->fence.cb_list);
}
spin_unlock_irqrestore(&rq->lock, flags);
+
+ /* Ensure that all who came before the barrier are flushed out */
+ __set_bit(I915_FENCE_FLAG_SENTINEL, &rq->fence.flags);
}
/*
diff --git a/drivers/gpu/drm/i915/i915_active.h
b/drivers/gpu/drm/i915/i915_active.h
index b3282ae7913c..9697592235fa 100644
--- a/drivers/gpu/drm/i915/i915_active.h
+++ b/drivers/gpu/drm/i915/i915_active.h
@@ -189,7 +189,8 @@ int i915_sw_fence_await_active(struct i915_sw_fence *fence,
int i915_request_await_active(struct i915_request *rq,
struct i915_active *ref,
unsigned int flags);
-#define I915_ACTIVE_AWAIT_ALL BIT(0)
+#define I915_ACTIVE_AWAIT_ACTIVE BIT(0)
+#define I915_ACTIVE_AWAIT_BARRIER BIT(1)
int i915_active_acquire(struct i915_active *ref);
bool i915_active_acquire_if_busy(struct i915_active *ref);
--
2.20.1
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