[PATCH 2/2] drm/i915: Use intel_context->pin_mutex only for context allocation
Maarten Lankhorst
maarten.lankhorst at linux.intel.com
Thu Jun 17 07:13:17 UTC 2021
Rename pin_mutex to alloc_mutex, and only use it for context allocation.
This will allow us to simplify __intel_context_do_pin_ww, which no longer
needs to run the pre_pin callback separately.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
drivers/gpu/drm/i915/gt/intel_context.c | 40 ++++++---------
drivers/gpu/drm/i915/gt/intel_context.h | 17 +++++--
drivers/gpu/drm/i915/gt/intel_context_param.c | 49 ++++++++++++-------
drivers/gpu/drm/i915/gt/intel_context_sseu.c | 2 +-
drivers/gpu/drm/i915/gt/intel_context_types.h | 2 +-
5 files changed, 62 insertions(+), 48 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c
index 4033184f13b9..e6dab37c4266 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.c
+++ b/drivers/gpu/drm/i915/gt/intel_context.c
@@ -53,7 +53,10 @@ int intel_context_alloc_state(struct intel_context *ce)
{
int err = 0;
- if (mutex_lock_interruptible(&ce->pin_mutex))
+ if (test_bit(CONTEXT_ALLOC_BIT, &ce->flags))
+ return 0;
+
+ if (mutex_lock_interruptible(&ce->alloc_mutex))
return -EINTR;
if (!test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
@@ -66,11 +69,12 @@ int intel_context_alloc_state(struct intel_context *ce)
if (unlikely(err))
goto unlock;
+ smp_mb__before_atomic();
set_bit(CONTEXT_ALLOC_BIT, &ce->flags);
}
unlock:
- mutex_unlock(&ce->pin_mutex);
+ mutex_unlock(&ce->alloc_mutex);
return err;
}
@@ -205,19 +209,11 @@ int __intel_context_do_pin_ww(struct intel_context *ce,
{
bool handoff = false;
void *vaddr;
- int err = 0;
-
- if (unlikely(!test_bit(CONTEXT_ALLOC_BIT, &ce->flags))) {
- err = intel_context_alloc_state(ce);
- if (err)
- return err;
- }
+ int err;
- /*
- * We always pin the context/ring/timeline here, to ensure a pin
- * refcount for __intel_context_active(), which prevent a lock
- * inversion of ce->pin_mutex vs dma_resv_lock().
- */
+ err = intel_context_alloc_state(ce);
+ if (err)
+ return err;
err = i915_gem_object_lock(ce->timeline->hwsp_ggtt->obj, ww);
if (!err && ce->ring->vma->obj)
@@ -237,24 +233,20 @@ int __intel_context_do_pin_ww(struct intel_context *ce,
if (err)
goto err_release;
- err = mutex_lock_interruptible(&ce->pin_mutex);
- if (err)
- goto err_post_unpin;
-
if (unlikely(intel_context_is_closed(ce))) {
err = -ENOENT;
- goto err_unlock;
+ goto err_post_unpin;
}
if (likely(!atomic_add_unless(&ce->pin_count, 1, 0))) {
err = intel_context_active_acquire(ce);
if (unlikely(err))
- goto err_unlock;
+ goto err_post_unpin;
err = ce->ops->pin(ce, vaddr);
if (err) {
intel_context_active_release(ce);
- goto err_unlock;
+ goto err_post_unpin;
}
CE_TRACE(ce, "pin ring:{start:%08x, head:%04x, tail:%04x}\n",
@@ -268,8 +260,6 @@ int __intel_context_do_pin_ww(struct intel_context *ce,
GEM_BUG_ON(!intel_context_is_pinned(ce)); /* no overflow! */
-err_unlock:
- mutex_unlock(&ce->pin_mutex);
err_post_unpin:
if (!handoff)
ce->ops->post_unpin(ce);
@@ -381,7 +371,7 @@ intel_context_init(struct intel_context *ce, struct intel_engine_cs *engine)
spin_lock_init(&ce->signal_lock);
INIT_LIST_HEAD(&ce->signals);
- mutex_init(&ce->pin_mutex);
+ mutex_init(&ce->alloc_mutex);
i915_active_init(&ce->active,
__intel_context_active, __intel_context_retire, 0);
@@ -393,7 +383,7 @@ void intel_context_fini(struct intel_context *ce)
intel_timeline_put(ce->timeline);
i915_vm_put(ce->vm);
- mutex_destroy(&ce->pin_mutex);
+ mutex_destroy(&ce->alloc_mutex);
i915_active_fini(&ce->active);
}
diff --git a/drivers/gpu/drm/i915/gt/intel_context.h b/drivers/gpu/drm/i915/gt/intel_context.h
index f83a73a2b39f..4cf6901fcb81 100644
--- a/drivers/gpu/drm/i915/gt/intel_context.h
+++ b/drivers/gpu/drm/i915/gt/intel_context.h
@@ -49,9 +49,16 @@ int intel_context_reconfigure_sseu(struct intel_context *ce,
* intel_context_is_pinned() remains stable.
*/
static inline int intel_context_lock_pinned(struct intel_context *ce)
- __acquires(ce->pin_mutex)
{
- return mutex_lock_interruptible(&ce->pin_mutex);
+ int ret = intel_context_alloc_state(ce);
+
+ if (ret)
+ return ret;
+
+ if (ce->state)
+ return i915_gem_object_lock_interruptible(ce->state->obj, NULL);
+ else
+ return i915_gem_object_lock_interruptible(ce->timeline->hwsp_ggtt->obj, NULL);
}
/**
@@ -76,9 +83,11 @@ intel_context_is_pinned(struct intel_context *ce)
* Releases the lock earlier acquired by intel_context_unlock_pinned().
*/
static inline void intel_context_unlock_pinned(struct intel_context *ce)
- __releases(ce->pin_mutex)
{
- mutex_unlock(&ce->pin_mutex);
+ if (ce->state)
+ return i915_gem_object_unlock(ce->state->obj);
+ else
+ return i915_gem_object_unlock(ce->timeline->hwsp_ggtt->obj);
}
int __intel_context_do_pin(struct intel_context *ce);
diff --git a/drivers/gpu/drm/i915/gt/intel_context_param.c b/drivers/gpu/drm/i915/gt/intel_context_param.c
index 412c36d1b1dd..eba026d63361 100644
--- a/drivers/gpu/drm/i915/gt/intel_context_param.c
+++ b/drivers/gpu/drm/i915/gt/intel_context_param.c
@@ -10,13 +10,34 @@
int intel_context_set_ring_size(struct intel_context *ce, long sz)
{
+ struct intel_ring *ring;
int err;
if (ce->engine->gt->submission_method == INTEL_SUBMISSION_RING)
return 0;
- if (intel_context_lock_pinned(ce))
- return -EINTR;
+ /* Try fast case (unallocated) first */
+ if (!test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
+ bool done = false;
+
+ err = mutex_lock_interruptible(&ce->alloc_mutex);
+ if (err)
+ return err;
+
+ if (!test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
+ ce->ring = __intel_context_ring_size(sz);
+ done = true;
+ }
+ mutex_unlock(&ce->alloc_mutex);
+
+ if (done)
+ return 0;
+ }
+
+ /* Context already allocated */
+ err = intel_context_lock_pinned(ce);
+ if (err)
+ return err;
err = i915_active_wait(&ce->active);
if (err < 0)
@@ -27,23 +48,17 @@ int intel_context_set_ring_size(struct intel_context *ce, long sz)
goto unlock;
}
- if (test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) {
- struct intel_ring *ring;
-
- /* Replace the existing ringbuffer */
- ring = intel_engine_create_ring(ce->engine, sz);
- if (IS_ERR(ring)) {
- err = PTR_ERR(ring);
- goto unlock;
- }
+ /* Replace the existing ringbuffer */
+ ring = intel_engine_create_ring(ce->engine, sz);
+ if (IS_ERR(ring)) {
+ err = PTR_ERR(ring);
+ goto unlock;
+ }
- intel_ring_put(ce->ring);
- ce->ring = ring;
+ intel_ring_put(ce->ring);
+ ce->ring = ring;
- /* Context image will be updated on next pin */
- } else {
- ce->ring = __intel_context_ring_size(sz);
- }
+ /* Context image will be updated on next pin */
unlock:
intel_context_unlock_pinned(ce);
diff --git a/drivers/gpu/drm/i915/gt/intel_context_sseu.c b/drivers/gpu/drm/i915/gt/intel_context_sseu.c
index e86d8255feec..447b278b107b 100644
--- a/drivers/gpu/drm/i915/gt/intel_context_sseu.c
+++ b/drivers/gpu/drm/i915/gt/intel_context_sseu.c
@@ -42,7 +42,7 @@ gen8_modify_rpcs(struct intel_context *ce, const struct intel_sseu sseu)
struct i915_request *rq;
int ret;
- lockdep_assert_held(&ce->pin_mutex);
+ assert_object_held(ce->state->obj);
/*
* If the context is not idle, we have to submit an ordered request to
diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
index ed8c447a7346..b104d5e9d3b6 100644
--- a/drivers/gpu/drm/i915/gt/intel_context_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
@@ -122,7 +122,7 @@ struct intel_context {
unsigned int active_count; /* protected by timeline->mutex */
atomic_t pin_count;
- struct mutex pin_mutex; /* guards pinning and associated on-gpuing */
+ struct mutex alloc_mutex; /* guards allocation (ops->alloc) */
/**
* active: Active tracker for the rq activity (inc. external) on this
--
2.31.0
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