Re: [PATCH 01/26] drm/i915/guc: Move GuC guc_id allocation under submission state sub-struct

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 10/7/2021 08:05, Matthew Brost wrote:
On Wed, Oct 06, 2021 at 08:06:41PM -0700, John Harrison wrote:
On 10/4/2021 15:06, Matthew Brost wrote:
Move guc_id allocation under submission state sub-struct as a future
patch will reuse the spin lock as a global submission state lock. Moving
this into sub-struct makes ownership of fields / lock clear.

Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
---
   drivers/gpu/drm/i915/gt/intel_context_types.h |  6 +-
   drivers/gpu/drm/i915/gt/uc/intel_guc.h        | 26 +++++----
   .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 56 ++++++++++---------
   3 files changed, 47 insertions(+), 41 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h
index 12252c411159..e7e3984aab78 100644
--- a/drivers/gpu/drm/i915/gt/intel_context_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_context_types.h
@@ -197,18 +197,18 @@ struct intel_context {
   	struct {
   		/**
   		 * @id: handle which is used to uniquely identify this context
-		 * with the GuC, protected by guc->contexts_lock
+		 * with the GuC, protected by guc->submission_state.lock
   		 */
   		u16 id;
   		/**
   		 * @ref: the number of references to the guc_id, when
   		 * transitioning in and out of zero protected by
-		 * guc->contexts_lock
+		 * guc->submission_state.lock
   		 */
   		atomic_t ref;
   		/**
   		 * @link: in guc->guc_id_list when the guc_id has no refs but is
-		 * still valid, protected by guc->contexts_lock
+		 * still valid, protected by guc->submission_state.lock
   		 */
   		struct list_head link;
   	} guc_id;
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
index 5dd174babf7a..65b5e8eeef96 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
@@ -70,17 +70,21 @@ struct intel_guc {
   		void (*disable)(struct intel_guc *guc);
   	} interrupts;
-	/**
-	 * @contexts_lock: protects guc_ids, guc_id_list, ce->guc_id.id, and
-	 * ce->guc_id.ref when transitioning in and out of zero
-	 */
-	spinlock_t contexts_lock;
-	/** @guc_ids: used to allocate unique ce->guc_id.id values */
-	struct ida guc_ids;
-	/**
-	 * @guc_id_list: list of intel_context with valid guc_ids but no refs
-	 */
-	struct list_head guc_id_list;
+	struct {
+		/**
+		 * @lock: protects everything in submission_state
+		 */
+		spinlock_t lock;
The old version also mentioned 'ce->guc_id.ref'. Should this not also
mention that transition? Or was the old comment inaccurate. I'm not seeing
any actual behaviour changes in the patch.


Can add that back in.

+		/**
+		 * @guc_ids: used to allocate new guc_ids
+		 */
+		struct ida guc_ids;
+		/**
+		 * @guc_id_list: list of intel_context with valid guc_ids but no
+		 * refs
+		 */
+		struct list_head guc_id_list;
+	} submission_state;
   	/**
   	 * @submission_supported: tracks whether we support GuC submission on
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 ba0de35f6323..ad5c18119d92 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -68,16 +68,16 @@
    * fence is used to stall all requests associated with this guc_id until the
    * corresponding G2H returns indicating the guc_id has been deregistered.
    *
- * guc_ids:
+ * submission_state.guc_ids:
    * Unique number associated with private GuC context data passed in during
    * context registration / submission / deregistration. 64k available. Simple ida
    * is used for allocation.
    *
- * Stealing guc_ids:
- * If no guc_ids are available they can be stolen from another context at
- * request creation time if that context is unpinned. If a guc_id can't be found
- * we punt this problem to the user as we believe this is near impossible to hit
- * during normal use cases.
+ * Stealing submission_state.guc_ids:
+ * If no submission_state.guc_ids are available they can be stolen from another
I would abbreviate this instance as well, submission_state.guc_id is quite
the mouthful. Unless this somehow magically links back to the structure
entry in the kerneldoc output?

It might, not really sure but agree the submission_state should be
dropped. Think changed because of global find replace.

Matt
Okay. With those nits fixed:
Reviewed by: John Harrison <John.C.Harrison@xxxxxxxxx>

John.

+ * context at request creation time if that context is unpinned. If a guc_id
+ * can't be found we punt this problem to the user as we believe this is near
+ * impossible to hit during normal use cases.
    *
    * Locking:
    * In the GuC submission code we have 3 basic spin locks which protect
@@ -89,7 +89,7 @@
    * sched_engine can be submitting at a time. Currently only one sched_engine is
    * used for all of GuC submission but that could change in the future.
    *
- * guc->contexts_lock
+ * guc->submission_state.lock
    * Protects guc_id allocation for the given GuC, i.e. only one context can be
    * doing guc_id allocation operations at a time for each GuC in the system.
    *
@@ -103,7 +103,7 @@
    *
    * Lock ordering rules:
    * sched_engine->lock -> ce->guc_state.lock
- * guc->contexts_lock -> ce->guc_state.lock
+ * guc->submission_state.lock -> ce->guc_state.lock
    *
    * Reset races:
    * When a full GT reset is triggered it is assumed that some G2H responses to
@@ -1148,9 +1148,9 @@ int intel_guc_submission_init(struct intel_guc *guc)
   	xa_init_flags(&guc->context_lookup, XA_FLAGS_LOCK_IRQ);
-	spin_lock_init(&guc->contexts_lock);
-	INIT_LIST_HEAD(&guc->guc_id_list);
-	ida_init(&guc->guc_ids);
+	spin_lock_init(&guc->submission_state.lock);
+	INIT_LIST_HEAD(&guc->submission_state.guc_id_list);
+	ida_init(&guc->submission_state.guc_ids);
   	return 0;
   }
@@ -1215,7 +1215,7 @@ static void guc_submit_request(struct i915_request *rq)
   static int new_guc_id(struct intel_guc *guc)
   {
-	return ida_simple_get(&guc->guc_ids, 0,
+	return ida_simple_get(&guc->submission_state.guc_ids, 0,
   			      GUC_MAX_LRC_DESCRIPTORS, GFP_KERNEL |
   			      __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
   }
@@ -1223,7 +1223,8 @@ static int new_guc_id(struct intel_guc *guc)
   static void __release_guc_id(struct intel_guc *guc, struct intel_context *ce)
   {
   	if (!context_guc_id_invalid(ce)) {
-		ida_simple_remove(&guc->guc_ids, ce->guc_id.id);
+		ida_simple_remove(&guc->submission_state.guc_ids,
+				  ce->guc_id.id);
   		reset_lrc_desc(guc, ce->guc_id.id);
   		set_context_guc_id_invalid(ce);
   	}
@@ -1235,9 +1236,9 @@ static void release_guc_id(struct intel_guc *guc, struct intel_context *ce)
   {
   	unsigned long flags;
-	spin_lock_irqsave(&guc->contexts_lock, flags);
+	spin_lock_irqsave(&guc->submission_state.lock, flags);
   	__release_guc_id(guc, ce);
-	spin_unlock_irqrestore(&guc->contexts_lock, flags);
+	spin_unlock_irqrestore(&guc->submission_state.lock, flags);
   }
   static int steal_guc_id(struct intel_guc *guc)
@@ -1245,10 +1246,10 @@ static int steal_guc_id(struct intel_guc *guc)
   	struct intel_context *ce;
   	int guc_id;
-	lockdep_assert_held(&guc->contexts_lock);
+	lockdep_assert_held(&guc->submission_state.lock);
-	if (!list_empty(&guc->guc_id_list)) {
-		ce = list_first_entry(&guc->guc_id_list,
+	if (!list_empty(&guc->submission_state.guc_id_list)) {
+		ce = list_first_entry(&guc->submission_state.guc_id_list,
   				      struct intel_context,
   				      guc_id.link);
@@ -1273,7 +1274,7 @@ static int assign_guc_id(struct intel_guc *guc, u16 *out)
   {
   	int ret;
-	lockdep_assert_held(&guc->contexts_lock);
+	lockdep_assert_held(&guc->submission_state.lock);
   	ret = new_guc_id(guc);
   	if (unlikely(ret < 0)) {
@@ -1295,7 +1296,7 @@ static int pin_guc_id(struct intel_guc *guc, struct intel_context *ce)
   	GEM_BUG_ON(atomic_read(&ce->guc_id.ref));
   try_again:
-	spin_lock_irqsave(&guc->contexts_lock, flags);
+	spin_lock_irqsave(&guc->submission_state.lock, flags);
   	might_lock(&ce->guc_state.lock);
@@ -1310,7 +1311,7 @@ static int pin_guc_id(struct intel_guc *guc, struct intel_context *ce)
   	atomic_inc(&ce->guc_id.ref);
   out_unlock:
-	spin_unlock_irqrestore(&guc->contexts_lock, flags);
+	spin_unlock_irqrestore(&guc->submission_state.lock, flags);
   	/*
   	 * -EAGAIN indicates no guc_id are available, let's retire any
@@ -1346,11 +1347,12 @@ static void unpin_guc_id(struct intel_guc *guc, struct intel_context *ce)
   	if (unlikely(context_guc_id_invalid(ce)))
   		return;
-	spin_lock_irqsave(&guc->contexts_lock, flags);
+	spin_lock_irqsave(&guc->submission_state.lock, flags);
   	if (!context_guc_id_invalid(ce) && list_empty(&ce->guc_id.link) &&
   	    !atomic_read(&ce->guc_id.ref))
-		list_add_tail(&ce->guc_id.link, &guc->guc_id_list);
-	spin_unlock_irqrestore(&guc->contexts_lock, flags);
+		list_add_tail(&ce->guc_id.link,
+			      &guc->submission_state.guc_id_list);
+	spin_unlock_irqrestore(&guc->submission_state.lock, flags);
   }
   static int __guc_action_register_context(struct intel_guc *guc,
@@ -1921,16 +1923,16 @@ static void guc_context_destroy(struct kref *kref)
   	 * returns indicating this context has been deregistered the guc_id is
   	 * returned to the pool of available guc_id.
   	 */
-	spin_lock_irqsave(&guc->contexts_lock, flags);
+	spin_lock_irqsave(&guc->submission_state.lock, flags);
   	if (context_guc_id_invalid(ce)) {
-		spin_unlock_irqrestore(&guc->contexts_lock, flags);
+		spin_unlock_irqrestore(&guc->submission_state.lock, flags);
   		__guc_context_destroy(ce);
   		return;
   	}
   	if (!list_empty(&ce->guc_id.link))
   		list_del_init(&ce->guc_id.link);
-	spin_unlock_irqrestore(&guc->contexts_lock, flags);
+	spin_unlock_irqrestore(&guc->submission_state.lock, flags);
   	/* Seal race with Reset */
   	spin_lock_irqsave(&ce->guc_state.lock, flags);




[Index of Archives]     [Linux DRI Users]     [Linux Intel Graphics]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux