[Intel-gfx] [PATCH 05/27] drm/i915: Add GT PM unpark worker

Matthew Brost
2021-08-20T22:50:47Z

Sometimes it is desirable to queue work up for later if the GT PM isn't
held and run that work on next GT PM unpark.

Implemented with a list in the GT of all pending work, workqueues in
the list, a callback to add a workqueue to the list, and finally a
wakeref post_get callback that iterates / drains the list + queues the
workqueues.

First user of this is deregistration of GuC contexts.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
---
drivers/gpu/drm/i915/Makefile | 1 +
drivers/gpu/drm/i915/gt/intel_gt.c | 3 ++
drivers/gpu/drm/i915/gt/intel_gt_pm.c | 8 ++++
.../gpu/drm/i915/gt/intel_gt_pm_unpark_work.c | 35 ++++++++++++++++
.../gpu/drm/i915/gt/intel_gt_pm_unpark_work.h | 40 +++++++++++++++++++
drivers/gpu/drm/i915/gt/intel_gt_types.h | 10 +++++
drivers/gpu/drm/i915/gt/uc/intel_guc.h | 8 ++--
.../gpu/drm/i915/gt/uc/intel_guc_submission.c | 15 +++++--
drivers/gpu/drm/i915/intel_wakeref.c | 5 +++
drivers/gpu/drm/i915/intel_wakeref.h | 1 +
10 files changed, 119 insertions(+), 7 deletions(-)
create mode 100644 drivers/gpu/drm/i915/gt/intel_gt_pm_unpark_work.c
create mode 100644 drivers/gpu/drm/i915/gt/intel_gt_pm_unpark_work.h

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 642a5b5a1b81..579bdc069f25 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -103,6 +103,7 @@ gt-y += \
gt/intel_gt_clock_utils.o \
gt/intel_gt_irq.o \
gt/intel_gt_pm.o \
+ gt/intel_gt_pm_unpark_work.o \
gt/intel_gt_pm_irq.o \
gt/intel_gt_requests.o \
gt/intel_gtt.o \
diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
index 62d40c986642..7e690e74baa2 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt.c
@@ -29,6 +29,9 @@ void intel_gt_init_early(struct intel_gt *gt, struct drm_i915_private *i915)

spin_lock_init(&gt->irq_lock);

+ spin_lock_init(&gt->pm_unpark_work_lock);
+ INIT_LIST_HEAD(&gt->pm_unpark_work_list);
+
INIT_LIST_HEAD(&gt->closed_vma);
spin_lock_init(&gt->closed_lock);

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
index dea8e2479897..564c11a3748b 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
@@ -90,6 +90,13 @@ static int __gt_unpark(struct intel_wakeref *wf)
return 0;
}

+static void __gt_unpark_work_queue(struct intel_wakeref *wf)
+{
+ struct intel_gt *gt = container_of(wf, typeof(*gt), wakeref);
+
+ intel_gt_pm_unpark_work_queue(gt);
+}
+
static int __gt_park(struct intel_wakeref *wf)
{
struct intel_gt *gt = container_of(wf, typeof(*gt), wakeref);
@@ -118,6 +125,7 @@ static int __gt_park(struct intel_wakeref *wf)

static const struct intel_wakeref_ops wf_ops = {
.get = __gt_unpark,
+ .post_get = __gt_unpark_work_queue,
.put = __gt_park,
};

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm_unpark_work.c b/drivers/gpu/drm/i915/gt/intel_gt_pm_unpark_work.c
new file mode 100644
index 000000000000..23162dbd0c35
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm_unpark_work.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2021 Intel Corporation
+ */
+
+#include "i915_drv.h"
+#include "intel_runtime_pm.h"
+#include "intel_gt_pm.h"
+
+void intel_gt_pm_unpark_work_queue(struct intel_gt *gt)
+{
+ struct intel_gt_pm_unpark_work *work, *next;
+ unsigned long flags;
+
+ spin_lock_irqsave(&gt->pm_unpark_work_lock, flags);
+ list_for_each_entry_safe(work, next,
+ &gt->pm_unpark_work_list, link) {
+ list_del_init(&work->link);
+ queue_work(system_unbound_wq, &work->worker);
+ }
+ spin_unlock_irqrestore(&gt->pm_unpark_work_lock, flags);
+}
+
+void intel_gt_pm_unpark_work_add(struct intel_gt *gt,
+ struct intel_gt_pm_unpark_work *work)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&gt->pm_unpark_work_lock, flags);
+ if (intel_gt_pm_is_awake(gt))
+ queue_work(system_unbound_wq, &work->worker);
+ else if (list_empty(&work->link))
+ list_add_tail(&work->link, &gt->pm_unpark_work_list);
+ spin_unlock_irqrestore(&gt->pm_unpark_work_lock, flags);
+}
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm_unpark_work.h b/drivers/gpu/drm/i915/gt/intel_gt_pm_unpark_work.h
new file mode 100644
index 000000000000..eaf1dc313aa2
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm_unpark_work.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2021 Intel Corporation
+ */
+
+#ifndef INTEL_GT_PM_UNPARK_WORK_H
+#define INTEL_GT_PM_UNPARK_WORK_H
+
+#include <linux/list.h>
+#include <linux/workqueue.h>
+
+struct intel_gt;
+
+/**
+ * struct intel_gt_pm_unpark_work - work to be scheduled when GT unparked
+ */
+struct intel_gt_pm_unpark_work {
+ /**
+ * @link: link into gt->pm_unpark_work_list of workers that need to be
+ * scheduled when GT is unpark, protected by gt->pm_unpark_work_lock
+ */
+ struct list_head link;
+ /** @worker: will be scheduled when GT unparked */
+ struct work_struct worker;
+};
+
+void intel_gt_pm_unpark_work_queue(struct intel_gt *gt);
+
+void intel_gt_pm_unpark_work_add(struct intel_gt *gt,
+ struct intel_gt_pm_unpark_work *work);
+
+static inline void
+intel_gt_pm_unpark_work_init(struct intel_gt_pm_unpark_work *work,
+ work_func_t fn)
+{
+ INIT_LIST_HEAD(&work->link);
+ INIT_WORK(&work->worker, fn);
+}
+
+#endif /* INTEL_GT_PM_UNPARK_WORK_H */
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_types.h b/drivers/gpu/drm/i915/gt/intel_gt_types.h
index a81e21bf1bd1..4480312f0add 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_types.h
@@ -96,6 +96,16 @@ struct intel_gt {
struct intel_wakeref wakeref;
atomic_t user_wakeref;

+ /**
+ * @pm_unpark_work_list: list of delayed work to scheduled which GT is
+ * unparked, protected by pm_unpark_work_lock
+ */
+ struct list_head pm_unpark_work_list;
+ /**
+ * @pm_unpark_work_lock: protects pm_unpark_work_list
+ */
+ spinlock_t pm_unpark_work_lock;
+
struct list_head closed_vma;
spinlock_t closed_lock; /* guards the list of closed_vma */

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
index 7358883f1540..023953e77553 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
@@ -19,6 +19,7 @@
#include "intel_uc_fw.h"
#include "i915_utils.h"
#include "i915_vma.h"
+#include "gt/intel_gt_pm_unpark_work.h"

struct __guc_ads_blob;

@@ -78,11 +79,12 @@ struct intel_guc {
*/
struct list_head destroyed_contexts;
/**
- * @destroyed_worker: worker to deregister contexts, need as we
+ * @destroyed_worker: Worker to deregister contexts, need as we
* need to take a GT PM reference and can't from destroy
- * function as it might be in an atomic context (no sleeping)
+ * function as it might be in an atomic context (no sleeping).
+ * Worker only issues deregister when GT is unparked.
*/
- struct work_struct destroyed_worker;
+ struct intel_gt_pm_unpark_work destroyed_worker;
} submission_state;

bool submission_supported;
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index f835e06e5f9f..dbf919801de2 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -1135,7 +1135,8 @@ int intel_guc_submission_init(struct intel_guc *guc)
INIT_LIST_HEAD(&guc->submission_state.guc_id_list);
ida_init(&guc->submission_state.guc_ids);
INIT_LIST_HEAD(&guc->submission_state.destroyed_contexts);
- INIT_WORK(&guc->submission_state.destroyed_worker, destroyed_worker_func);
+ intel_gt_pm_unpark_work_init(&guc->submission_state.destroyed_worker,
+ destroyed_worker_func);

return 0;
}
@@ -1942,13 +1943,18 @@ static void deregister_destroyed_contexts(struct intel_guc *guc)

static void destroyed_worker_func(struct work_struct *w)
{
- struct intel_guc *guc = container_of(w, struct intel_guc,
+ struct intel_gt_pm_unpark_work *destroyed_worker =
+ container_of(w, struct intel_gt_pm_unpark_work, worker);
+ struct intel_guc *guc = container_of(destroyed_worker, struct intel_guc,
submission_state.destroyed_worker);
struct intel_gt *gt = guc_to_gt(guc);
int tmp;

- with_intel_gt_pm(gt, tmp)
+ with_intel_gt_pm_if_awake(gt, tmp)
deregister_destroyed_contexts(guc);
+
+ if (!list_empty(&guc->submission_state.destroyed_contexts))
+ intel_gt_pm_unpark_work_add(gt, destroyed_worker);
}

static void guc_context_destroy(struct kref *kref)
@@ -1985,7 +1991,8 @@ static void guc_context_destroy(struct kref *kref)
* take the GT PM for the first time which isn't allowed from an atomic
* context.
*/
- queue_work(system_unbound_wq, &guc->submission_state.destroyed_worker);
+ intel_gt_pm_unpark_work_add(guc_to_gt(guc),
+ &guc->submission_state.destroyed_worker);
}

static int guc_context_alloc(struct intel_context *ce)
diff --git a/drivers/gpu/drm/i915/intel_wakeref.c b/drivers/gpu/drm/i915/intel_wakeref.c
index dfd87d082218..282fc4f312e3 100644
--- a/drivers/gpu/drm/i915/intel_wakeref.c
+++ b/drivers/gpu/drm/i915/intel_wakeref.c
@@ -24,6 +24,8 @@ static void rpm_put(struct intel_wakeref *wf)

int __intel_wakeref_get_first(struct intel_wakeref *wf)
{
+ bool do_post = false;
+
/*
* Treat get/put as different subclasses, as we may need to run
* the put callback from under the shrinker and do not want to
@@ -44,8 +46,11 @@ int __intel_wakeref_get_first(struct intel_wakeref *wf)
}

smp_mb__before_atomic(); /* release wf->count */
+ do_post = true;
}
atomic_inc(&wf->count);
+ if (do_post && wf->ops->post_get)
+ wf->ops->post_get(wf);
mutex_unlock(&wf->mutex);

INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0);
diff --git a/drivers/gpu/drm/i915/intel_wakeref.h b/drivers/gpu/drm/i915/intel_wakeref.h
index 545c8f277c46..ef7e6a698e8a 100644
--- a/drivers/gpu/drm/i915/intel_wakeref.h
+++ b/drivers/gpu/drm/i915/intel_wakeref.h
@@ -30,6 +30,7 @@ typedef depot_stack_handle_t intel_wakeref_t;

struct intel_wakeref_ops {
int (*get)(struct intel_wakeref *wf);
+ void (*post_get)(struct intel_wakeref *wf);
int (*put)(struct intel_wakeref *wf);
};

--
2.32.0