The principal motivation for this was to try and eliminate the
struct_mutex from i915_gem_suspend - but we still need to hold the mutex
current for the i915_gem_context_lost(). (The issue there is that there
may be an indirect lockdep cycle between cpu_hotplug (i.e. suspend) and
struct_mutex via the stop_machine().) For the moment, enabling last
request tracking for the engine, allows us to do busyness checking and
waiting without requiring the struct_mutex - which is useful in its own
right.
As a side-effect of having a robust means for tracking engine busyness,
we can replace our other busyness heuristic, that of comparing against
the last submitted seqno. For paranoid reasons, we have a semi-ordered
check of that seqno inside the hangchecker, which we can now improve to
an ordered check of the engine's busyness (removing a locked xchg in the
process).
v2: Pass along "bool interruptible" as being unlocked we cannot rely on
i915->mm.interruptible being stable or even under our control.
v3: Replace check Ironlake i915_gpu_busy() with the common precalculated value
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_debugfs.c | 2 +-
drivers/gpu/drm/i915/i915_drv.h | 3 ++-
drivers/gpu/drm/i915/i915_gem.c | 31 ++++++++++++++----------------
drivers/gpu/drm/i915/i915_gem_evict.c | 6 +++---
drivers/gpu/drm/i915/i915_gem_gtt.c | 2 +-
drivers/gpu/drm/i915/i915_gem_request.c | 7 ++++---
drivers/gpu/drm/i915/i915_gem_request.h | 11 +++++++++++
drivers/gpu/drm/i915/i915_gem_shrinker.c | 2 +-
drivers/gpu/drm/i915/i915_irq.c | 9 +--------
drivers/gpu/drm/i915/intel_engine_cs.c | 8 +++++++-
drivers/gpu/drm/i915/intel_pm.c | 12 ++----------
drivers/gpu/drm/i915/intel_ringbuffer.c | 18 -----------------
drivers/gpu/drm/i915/intel_ringbuffer.h | 33 ++++++++++++++++++++------------
13 files changed, 68 insertions(+), 76 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 24d63e271f4b..1faea382dfeb 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -4925,7 +4925,7 @@ i915_drop_caches_set(void *data, u64 val)
return ret;
if (val & DROP_ACTIVE) {
- ret = i915_gem_wait_for_idle(dev_priv);
+ ret = i915_gem_wait_for_idle(dev_priv, true);
if (ret)
goto unlock;
}
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index abdfb97096e2..6eff31202336 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3233,7 +3233,8 @@ int __must_check i915_gem_init(struct drm_device *dev);
int __must_check i915_gem_init_hw(struct drm_device *dev);
void i915_gem_init_swizzling(struct drm_device *dev);
void i915_gem_cleanup_engines(struct drm_device *dev);
-int __must_check i915_gem_wait_for_idle(struct drm_i915_private *dev_priv);
+int __must_check i915_gem_wait_for_idle(struct drm_i915_private *dev_priv,
+ bool interruptible);
int __must_check i915_gem_suspend(struct drm_device *dev);
void i915_gem_resume(struct drm_device *dev);
int i915_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf);
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 8946c52e09fb..434171a6d586 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2438,13 +2438,18 @@ static void i915_gem_reset_engine_status(struct intel_engine_cs *engine)
static void i915_gem_reset_engine_cleanup(struct intel_engine_cs *engine)
{
+ struct drm_i915_gem_request *request;
struct intel_ring *ring;
+ request = i915_gem_active_peek(&engine->last_request,
+ &engine->i915->drm.struct_mutex);
+
/* Mark all pending requests as complete so that any concurrent
* (lockless) lookup doesn't try and wait upon the request as we
* reset it.
*/
- intel_engine_init_seqno(engine, engine->last_submitted_seqno);
+ if (request)
+ intel_engine_init_seqno(engine, request->fence.seqno);
/*
* Clear the execlists queue up before freeing the requests, as those
@@ -2466,15 +2471,9 @@ static void i915_gem_reset_engine_cleanup(struct intel_engine_cs *engine)
* implicit references on things like e.g. ppgtt address spaces through
* the request.
*/
- if (!list_empty(&engine->request_list)) {
- struct drm_i915_gem_request *request;
-
- request = list_last_entry(&engine->request_list,
- struct drm_i915_gem_request,
- link);
-
+ if (request)
i915_gem_request_retire_upto(request);
- }
+ GEM_BUG_ON(intel_engine_is_active(engine));
/* Having flushed all requests from all queues, we know that all
* ringbuffers must now be empty. However, since we do not reclaim
@@ -2897,18 +2896,17 @@ destroy:
return 0;
}
-int i915_gem_wait_for_idle(struct drm_i915_private *dev_priv)
+int i915_gem_wait_for_idle(struct drm_i915_private *dev_priv,
+ bool interruptible)
{
struct intel_engine_cs *engine;
int ret;
- lockdep_assert_held(&dev_priv->drm.struct_mutex);
-
for_each_engine(engine, dev_priv) {
if (engine->last_context == NULL)
continue;
- ret = intel_engine_idle(engine);
+ ret = intel_engine_idle(engine, interruptible);
if (ret)
return ret;
}
@@ -4080,11 +4078,10 @@ struct i915_vma *i915_gem_obj_to_ggtt_view(struct drm_i915_gem_object *obj,
return NULL;
}
-int
-i915_gem_suspend(struct drm_device *dev)
+int i915_gem_suspend(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = to_i915(dev);
- int ret = 0;
+ int ret;
intel_suspend_gt_powersave(dev_priv);
@@ -4102,7 +4099,7 @@ i915_gem_suspend(struct drm_device *dev)
if (ret)
goto err;
- ret = i915_gem_wait_for_idle(dev_priv);
+ ret = i915_gem_wait_for_idle(dev_priv, true);
if (ret)
goto err;
diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
index 7be425826539..f76c06e92677 100644
--- a/drivers/gpu/drm/i915/i915_gem_evict.c
+++ b/drivers/gpu/drm/i915/i915_gem_evict.c
@@ -39,7 +39,7 @@ gpu_is_idle(struct drm_i915_private *dev_priv)
struct intel_engine_cs *engine;
for_each_engine(engine, dev_priv) {
- if (!list_empty(&engine->request_list))
+ if (intel_engine_is_active(engine))
return false;
}
@@ -167,7 +167,7 @@ search_again:
if (ret)
return ret;
- ret = i915_gem_wait_for_idle(dev_priv);
+ ret = i915_gem_wait_for_idle(dev_priv, true);
if (ret)
return ret;
@@ -272,7 +272,7 @@ int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle)
return ret;
}
- ret = i915_gem_wait_for_idle(dev_priv);
+ ret = i915_gem_wait_for_idle(dev_priv, true);
if (ret)
return ret;
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index db97155074d3..c1d79978f409 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -2248,7 +2248,7 @@ static bool do_idling(struct drm_i915_private *dev_priv)
if (unlikely(ggtt->do_idle_maps)) {
dev_priv->mm.interruptible = false;
- if (i915_gem_wait_for_idle(dev_priv)) {
+ if (i915_gem_wait_for_idle(dev_priv, false)) {
DRM_ERROR("Failed to wait for idle; VT'd may hang.\n");
/* Wait a bit, in hopes it avoids the hang */
udelay(10);
diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index 3fecb8f0e041..1f91dc8c4171 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -265,7 +265,7 @@ static int i915_gem_init_seqno(struct drm_i915_private *dev_priv, u32 seqno)
/* Carefully retire all requests without writing to the rings */
for_each_engine(engine, dev_priv) {
- ret = intel_engine_idle(engine);
+ ret = intel_engine_idle(engine, true);
if (ret)
return ret;
}
@@ -486,7 +486,8 @@ void __i915_add_request(struct drm_i915_gem_request *request,
*/
request->emitted_jiffies = jiffies;
request->previous_seqno = engine->last_submitted_seqno;
- smp_store_mb(engine->last_submitted_seqno, request->fence.seqno);
+ engine->last_submitted_seqno = request->fence.seqno;
+ i915_gem_active_set(&engine->last_request, request);
list_add_tail(&request->link, &engine->request_list);
list_add_tail(&request->ring_link, &ring->request_list);
@@ -757,7 +758,7 @@ void i915_gem_retire_requests(struct drm_i915_private *dev_priv)
for_each_engine(engine, dev_priv) {
engine_retire_requests(engine);
- if (list_empty(&engine->request_list))
+ if (!intel_engine_is_active(engine))
dev_priv->gt.active_engines &= ~intel_engine_flag(engine);
}
diff --git a/drivers/gpu/drm/i915/i915_gem_request.h b/drivers/gpu/drm/i915/i915_gem_request.h
index 15495d1e48e8..3496e28785e7 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.h
+++ b/drivers/gpu/drm/i915/i915_gem_request.h
@@ -29,6 +29,17 @@
#include "i915_gem.h"
+struct intel_wait {
+ struct rb_node node;
+ struct task_struct *tsk;
+ u32 seqno;
+};
+
+struct intel_signal_node {
+ struct rb_node node;
+ struct intel_wait wait;
+};
+
/**
* Request queue structure.
*
diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c
index 1341cb55b6f1..23d70376b104 100644
--- a/drivers/gpu/drm/i915/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c
@@ -412,7 +412,7 @@ i915_gem_shrinker_vmap(struct notifier_block *nb, unsigned long event, void *ptr
return NOTIFY_DONE;
/* Force everything onto the inactive lists */
- ret = i915_gem_wait_for_idle(dev_priv);
+ ret = i915_gem_wait_for_idle(dev_priv, false);
if (ret)
goto out;
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index e58650096426..006a855877ad 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2805,13 +2805,6 @@ static void gen8_disable_vblank(struct drm_device *dev, unsigned int pipe)
}
static bool
-ring_idle(struct intel_engine_cs *engine, u32 seqno)
-{
- return i915_seqno_passed(seqno,
- READ_ONCE(engine->last_submitted_seqno));
-}
-
-static bool
ipehr_is_semaphore_wait(struct intel_engine_cs *engine, u32 ipehr)
{
if (INTEL_GEN(engine->i915) >= 8) {
@@ -3131,7 +3124,7 @@ static void i915_hangcheck_elapsed(struct work_struct *work)
user_interrupts = 0;
if (engine->hangcheck.seqno == seqno) {
- if (ring_idle(engine, seqno)) {
+ if (!intel_engine_is_active(engine)) {
engine->hangcheck.action = HANGCHECK_IDLE;
if (busy) {
/* Safeguard against driver failure */
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index f495969f749b..e9b301ae2d0c 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -166,6 +166,12 @@ void intel_engine_init_hangcheck(struct intel_engine_cs *engine)
memset(&engine->hangcheck, 0, sizeof(engine->hangcheck));
}
+static void intel_engine_init_requests(struct intel_engine_cs *engine)
+{
+ init_request_active(&engine->last_request, NULL);
+ INIT_LIST_HEAD(&engine->request_list);
+}
+
/**
* intel_engines_setup_common - setup engine state not requiring hw access
* @engine: Engine to setup.
@@ -177,13 +183,13 @@ void intel_engine_init_hangcheck(struct intel_engine_cs *engine)
*/
void intel_engine_setup_common(struct intel_engine_cs *engine)
{
- INIT_LIST_HEAD(&engine->request_list);
INIT_LIST_HEAD(&engine->buffers);
INIT_LIST_HEAD(&engine->execlist_queue);
spin_lock_init(&engine->execlist_lock);
engine->fence_context = fence_context_alloc(1);
+ intel_engine_init_requests(engine);
intel_engine_init_hangcheck(engine);
i915_gem_batch_pool_init(engine, &engine->batch_pool);
}
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 6bd352a8f30e..eedcacef7d5c 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6328,19 +6328,11 @@ EXPORT_SYMBOL_GPL(i915_gpu_lower);
*/
bool i915_gpu_busy(void)
{
- struct drm_i915_private *dev_priv;
- struct intel_engine_cs *engine;
bool ret = false;
spin_lock_irq(&mchdev_lock);
- if (!i915_mch_dev)
- goto out_unlock;
- dev_priv = i915_mch_dev;
-
- for_each_engine(engine, dev_priv)
- ret |= !list_empty(&engine->request_list);
-
-out_unlock:
+ if (i915_mch_dev)
+ ret = i915_mch_dev->gt.awake;
spin_unlock_irq(&mchdev_lock);
return ret;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 4593a65cae84..322274a239e4 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -2227,24 +2227,6 @@ void intel_engine_cleanup(struct intel_engine_cs *engine)
engine->i915 = NULL;
}
-int intel_engine_idle(struct intel_engine_cs *engine)
-{
- struct drm_i915_gem_request *req;
-
- /* Wait upon the last request to be completed */
- if (list_empty(&engine->request_list))
- return 0;
-
- req = list_entry(engine->request_list.prev,
- struct drm_i915_gem_request,
- link);
-
- /* Make sure we do not trigger any retires */
- return i915_wait_request(req,
- req->i915->mm.interruptible,
- NULL, NULL);
-}
-
int intel_ring_alloc_request_extras(struct drm_i915_gem_request *request)
{
int ret;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 88952bf10b9d..43e545e44352 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -3,6 +3,7 @@
#include <linux/hashtable.h>
#include "i915_gem_batch_pool.h"
+#include "i915_gem_request.h"
#define I915_CMD_HASH_ORDER 9
@@ -307,6 +308,13 @@ struct intel_engine_cs {
*/
u32 last_submitted_seqno;
+ /* An RCU guarded pointer to the last request. No reference is
+ * held to the request, users must carefully acquire a reference to
+ * the request using i915_gem_active_get_request_rcu(), or hold the
+ * struct_mutex.
+ */
+ struct i915_gem_active last_request;
+
struct i915_gem_context *last_context;
struct intel_engine_hangcheck hangcheck;
@@ -465,7 +473,6 @@ static inline u32 intel_ring_offset(struct intel_ring *ring, u32 value)
int __intel_ring_space(int head, int tail, int size);
void intel_ring_update_space(struct intel_ring *ring);
-int __must_check intel_engine_idle(struct intel_engine_cs *engine);
void intel_engine_init_seqno(struct intel_engine_cs *engine, u32 seqno);
int intel_init_pipe_control(struct intel_engine_cs *engine, int size);
@@ -475,6 +482,14 @@ void intel_engine_setup_common(struct intel_engine_cs *engine);
int intel_engine_init_common(struct intel_engine_cs *engine);
void intel_engine_cleanup_common(struct intel_engine_cs *engine);
+static inline int intel_engine_idle(struct intel_engine_cs *engine,
+ bool interruptible)
+{
+ /* Wait upon the last request to be completed */
+ return i915_gem_active_wait_unlocked(&engine->last_request,
+ interruptible, NULL, NULL);
+}
+
int intel_init_render_ring_buffer(struct intel_engine_cs *engine);
int intel_init_bsd_ring_buffer(struct intel_engine_cs *engine);
int intel_init_bsd2_ring_buffer(struct intel_engine_cs *engine);
@@ -504,17 +519,6 @@ static inline u32 intel_hws_seqno_address(struct intel_engine_cs *engine)
}
/* intel_breadcrumbs.c -- user interrupt bottom-half for waiters */
-struct intel_wait {
- struct rb_node node;
- struct task_struct *tsk;
- u32 seqno;
-};
-
-struct intel_signal_node {
- struct rb_node node;
- struct intel_wait wait;
-};
-
int intel_engine_init_breadcrumbs(struct intel_engine_cs *engine);
static inline void intel_wait_init(struct intel_wait *wait, u32 seqno)
@@ -561,4 +565,9 @@ void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine);
unsigned int intel_kick_waiters(struct drm_i915_private *i915);
unsigned int intel_kick_signalers(struct drm_i915_private *i915);
+static inline bool intel_engine_is_active(struct intel_engine_cs *engine)
+{
+ return i915_gem_active_isset(&engine->last_request);
+}
+
#endif /* _INTEL_RINGBUFFER_H_ */
--
2.8.1
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