[Intel-gfx] [PATCH 2/3] drm/i915: Complete kerneldoc for struct i915_gem_context

Chris Wilson chris at chris-wilson.co.uk
Fri Dec 30 09:27:20 UTC 2016


The existing kerneldoc was outdated, so time for a refresh.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_drv.h            | 214 ++++++++++++++++++++++++-----
 drivers/gpu/drm/i915/i915_gem.c            |  26 ++--
 drivers/gpu/drm/i915/i915_gem_context.c    |  33 ++---
 drivers/gpu/drm/i915/i915_gem_execbuffer.c |   2 +-
 drivers/gpu/drm/i915/i915_gpu_error.c      |   2 +-
 drivers/gpu/drm/i915/intel_lrc.c           |   2 +-
 6 files changed, 211 insertions(+), 68 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 00ecbb4da25e..c8617360c912 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1051,44 +1051,118 @@ enum i915_cache_level {
 #define DEFAULT_CONTEXT_HANDLE 0
 
 /**
- * struct i915_gem_context - as the name implies, represents a context.
- * @ref: reference count.
- * @user_handle: userspace tracking identity for this context.
- * @remap_slice: l3 row remapping information.
- * @flags: context specific flags:
- *         CONTEXT_NO_ZEROMAP: do not allow mapping things to page 0.
- * @file_priv: filp associated with this context (NULL for global default
- *	       context).
- * @hang_stats: information about the role of this context in possible GPU
- *		hangs.
- * @ppgtt: virtual memory space used by this context.
- * @legacy_hw_ctx: render context backing object and whether it is correctly
- *                initialized (legacy ring submission mechanism only).
- * @link: link in the global list of contexts.
+ * struct i915_gem_context - client state
  *
- * Contexts are memory images used by the hardware to store copies of their
- * internal state.
+ * The struct i915_gem_context represents the combined view of the driver and
+ * logical hardware state for a particular client.
  */
 struct i915_gem_context {
-	struct kref ref;
+	/**
+	 * @i915: i915 device backpointer
+	 */
 	struct drm_i915_private *i915;
+
+	/**
+	 * @file_priv: owning file descriptor
+	 */
 	struct drm_i915_file_private *file_priv;
+
+	/**
+	 * @ppgtt: unique address space (GTT)
+	 *
+	 * In full-ppgtt mode, each context has its own address space ensuring
+	 * complete seperation of one client from all others.
+	 */
 	struct i915_hw_ppgtt *ppgtt;
+
+	/**
+	 * @pid: process id of creator
+	 *
+	 * Note that who created the context may not be the principle user,
+	 * as the context may be shared across a local socket. However,
+	 * that should only affect the default context, all contexts created
+	 * explicitly by the client are expected to be isolated.
+	 */
 	struct pid *pid;
+
+	/**
+	 * @name: arbitrary name
+	 *
+	 * A name is constructed for the context from the creator's process
+	 * name, pid and user handle in order to uniquely identify the
+	 * context in messages.
+	 */
 	const char *name;
 
+	/**
+	 * @link: place with &drm_i915_private.context_list
+	 */
+	struct list_head link;
+
+	/**
+	 * @ref: reference count
+	 *
+	 * A reference to a context is held by both the client who created it
+	 * and on each request submitted to the hardware using the request
+	 * (to ensure the hardware has access to the state until it has
+	 * finished all pending writes).
+	 */
+	struct kref ref;
+
+	/**
+	 * @flags: small set of booleans
+	 */
 	unsigned long flags;
 #define CONTEXT_NO_ZEROMAP		BIT(0)
-#define CONTEXT_NO_ERROR_CAPTURE	BIT(1)
+#define CONTEXT_NO_ERROR_CAPTURE	1
+#define CONTEXT_CLOSED			2
+#define CONTEXT_BANNABLE		3
+#define CONTEXT_BANNED			4
+#define CONTEXT_FORCE_SINGLE_SUBMISSION	5
 
-	/* Unique identifier for this context, used by the hw for tracking */
+	/**
+	 * @hw_id: - unique identifier for the context
+	 *
+	 * The hardware needs to uniquely identify the context for a few
+	 * functions like fault reporting, PASID, scheduling. The
+	 * &drm_i915_private.context_hw_ida is used to assign a unqiue
+	 * id for the lifetime of the context.
+	 */
 	unsigned int hw_id;
+
+	/**
+	 * @user_handle: userspace identifier
+	 *
+	 * A unique per-file identifier is generated from
+	 * &drm_i915_file_private.contexts.
+	 */
 	u32 user_handle;
-	int priority; /* greater priorities are serviced first */
 
+	/**
+	 * @priority: execution and service priority
+	 *
+	 * All clients are equal, but some are more equal than others!
+	 *
+	 * Requests from a context with a greater (more positive) value of
+	 * @priority will be executed before those with a lower @priority
+	 * value, forming a simple QoS.
+	 *
+	 * The kernel_context is assigned the minimum priority.
+	 */
+	int priority;
+
+	/**
+	 * @ggtt_alignment: alignment restriction for context objects
+	 */
 	u32 ggtt_alignment;
+	/**
+	 * @ggtt_offset_bias: placement restriction for context objects
+	 */
 	u32 ggtt_offset_bias;
 
+	/**
+	 * @engine: per-engine logical HW state
+	 */
 	struct intel_context {
 		struct i915_vma *state;
 		struct intel_ring *ring;
@@ -1097,27 +1171,105 @@ struct i915_gem_context {
 		int pin_count;
 		bool initialised;
 	} engine[I915_NUM_ENGINES];
+
+	/**
+	 * @ring_size: size for allocating the per-engine ring buffer
+	 */
 	u32 ring_size;
+	/**
+	 * @desc_template: common/invariant fields for the HW context descriptor
+	 */
 	u32 desc_template;
-	struct atomic_notifier_head status_notifier;
-	bool execlists_force_single_submission;
-
-	struct list_head link;
 
-	u8 remap_slice;
-	bool closed:1;
-	bool bannable:1;
-	bool banned:1;
+	/**
+	 * @status_notifier: list of callbacks
+	 */
+	struct atomic_notifier_head status_notifier;
 
-	unsigned int guilty_count; /* guilty of a hang */
-	unsigned int active_count; /* active during hang */
+	/**
+	 * @guilty_count: How many times this context has caused a GPU hang.
+	 */
+	unsigned int guilty_count;
+	/**
+	 * @active_count: How many times this context was active during a GPU
+	 * hang, but did not cause it.
+	 */
+	unsigned int active_count;
 
 #define CONTEXT_SCORE_GUILTY		10
 #define CONTEXT_SCORE_BAN_THRESHOLD	40
-	/* Accumulated score of hangs caused by this context */
+	/**
+	 * @ban_score: Accumulated score of all hangs caused by this context.
+	 */
 	int ban_score;
+
+	/**
+	 * @remap_slice: Bitmask of cache lines that need remapping
+	 */
+	u8 remap_slice;
 };
 
+static inline bool i915_gem_context_is_closed(const struct i915_gem_context *ctx)
+{
+	return test_bit(CONTEXT_CLOSED, &ctx->flags);
+}
+
+static inline void i915_gem_context_set_closed(struct i915_gem_context *ctx)
+{
+	GEM_BUG_ON(i915_gem_context_is_closed(ctx));
+	set_bit(CONTEXT_CLOSED, &ctx->flags);
+}
+
+static inline bool i915_gem_context_no_error_capture(const struct i915_gem_context *ctx)
+{
+	return test_bit(CONTEXT_NO_ERROR_CAPTURE, &ctx->flags);
+}
+
+static inline void i915_gem_context_set_no_error_capture(struct i915_gem_context *ctx)
+{
+	return set_bit(CONTEXT_NO_ERROR_CAPTURE, &ctx->flags);
+}
+
+static inline void i915_gem_context_unset_no_error_capture(struct i915_gem_context *ctx)
+{
+	return clear_bit(CONTEXT_NO_ERROR_CAPTURE, &ctx->flags);
+}
+
+static inline bool i915_gem_context_is_bannable(const struct i915_gem_context *ctx)
+{
+	return test_bit(CONTEXT_BANNABLE, &ctx->flags);
+}
+
+static inline void i915_gem_context_set_bannable(struct i915_gem_context *ctx)
+{
+	set_bit(CONTEXT_BANNABLE, &ctx->flags);
+}
+
+static inline void i915_gem_context_unset_bannable(struct i915_gem_context *ctx)
+{
+	clear_bit(CONTEXT_BANNABLE, &ctx->flags);
+}
+
+static inline bool i915_gem_context_is_banned(const struct i915_gem_context *ctx)
+{
+	return test_bit(CONTEXT_BANNED, &ctx->flags);
+}
+
+static inline void i915_gem_context_set_banned(struct i915_gem_context *ctx)
+{
+	set_bit(CONTEXT_BANNED, &ctx->flags);
+}
+
+static inline bool i915_gem_context_force_single_submission(const struct i915_gem_context *ctx)
+{
+	return test_bit(CONTEXT_FORCE_SINGLE_SUBMISSION, &ctx->flags);
+}
+
+static inline void i915_gem_context_set_force_single_submission(struct i915_gem_context *ctx)
+{
+	set_bit(CONTEXT_FORCE_SINGLE_SUBMISSION, &ctx->flags);
+}
+
 enum fb_op_origin {
 	ORIGIN_GTT,
 	ORIGIN_CPU,
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 92560a776e17..d8760acf8001 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2656,34 +2656,24 @@ void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
 	goto out_unlock;
 }
 
-static bool i915_context_is_banned(const struct i915_gem_context *ctx)
+static bool ban_context(const struct i915_gem_context *ctx)
 {
-	if (ctx->banned)
-		return true;
-
-	if (!ctx->bannable)
-		return false;
-
-	if (ctx->ban_score >= CONTEXT_SCORE_BAN_THRESHOLD) {
-		DRM_DEBUG("context hanging too often, banning!\n");
-		return true;
-	}
-
-	return false;
+	return (i915_gem_context_is_bannable(ctx) &&
+		ctx->ban_score >= CONTEXT_SCORE_BAN_THRESHOLD);
 }
 
 static void i915_gem_context_mark_guilty(struct i915_gem_context *ctx)
 {
-	ctx->ban_score += CONTEXT_SCORE_GUILTY;
-
-	ctx->banned = i915_context_is_banned(ctx);
 	ctx->guilty_count++;
+	ctx->ban_score += CONTEXT_SCORE_GUILTY;
+	if (ban_context(ctx))
+		i915_gem_context_set_banned(ctx);
 
 	DRM_DEBUG_DRIVER("context %s marked guilty (score %d) banned? %s\n",
 			 ctx->name, ctx->ban_score,
-			 yesno(ctx->banned));
+			 yesno(i915_gem_context_is_banned(ctx)));
 
-	if (!ctx->banned || IS_ERR_OR_NULL(ctx->file_priv))
+	if (!i915_gem_context_is_banned(ctx) || IS_ERR_OR_NULL(ctx->file_priv))
 		return;
 
 	ctx->file_priv->context_bans++;
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 48e4ed5bb209..5c0c7064d532 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -141,7 +141,7 @@ void i915_gem_context_free(struct kref *ctx_ref)
 
 	lockdep_assert_held(&ctx->i915->drm.struct_mutex);
 	trace_i915_context_free(ctx);
-	GEM_BUG_ON(!ctx->closed);
+	GEM_BUG_ON(!i915_gem_context_is_closed(ctx));
 
 	i915_ppgtt_put(ctx->ppgtt);
 
@@ -228,8 +228,7 @@ static void i915_ppgtt_close(struct i915_address_space *vm)
 
 static void context_close(struct i915_gem_context *ctx)
 {
-	GEM_BUG_ON(ctx->closed);
-	ctx->closed = true;
+	i915_gem_context_set_closed(ctx);
 	if (ctx->ppgtt)
 		i915_ppgtt_close(&ctx->ppgtt->base);
 	ctx->file_priv = ERR_PTR(-EBADF);
@@ -329,7 +328,7 @@ __create_hw_context(struct drm_i915_private *dev_priv,
 	 * is no remap info, it will be a NOP. */
 	ctx->remap_slice = ALL_L3_SLICES(dev_priv);
 
-	ctx->bannable = true;
+	i915_gem_context_set_bannable(ctx);
 	ctx->ring_size = 4 * PAGE_SIZE;
 	ctx->desc_template = GEN8_CTX_ADDRESSING_MODE(dev_priv) <<
 			     GEN8_CTX_ADDRESSING_MODE_SHIFT;
@@ -418,8 +417,9 @@ i915_gem_context_create_gvt(struct drm_device *dev)
 	if (IS_ERR(ctx))
 		goto out;
 
-	ctx->closed = true; /* not user accessible */
-	ctx->execlists_force_single_submission = true;
+	i915_gem_context_set_closed(ctx); /* not user accessible */
+	i915_gem_context_unset_bannable(ctx);
+	i915_gem_context_set_force_single_submission(ctx);
 	ctx->ring_size = 512 * PAGE_SIZE; /* Max ring buffer size */
 out:
 	mutex_unlock(&dev->struct_mutex);
@@ -468,6 +468,7 @@ int i915_gem_context_init(struct drm_i915_private *dev_priv)
 		return PTR_ERR(ctx);
 	}
 
+	i915_gem_context_unset_bannable(ctx);
 	ctx->priority = I915_PRIORITY_MIN; /* lowest priority; idle task */
 	dev_priv->kernel_context = ctx;
 
@@ -1040,10 +1041,10 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
 			args->value = to_i915(dev)->ggtt.base.total;
 		break;
 	case I915_CONTEXT_PARAM_NO_ERROR_CAPTURE:
-		args->value = !!(ctx->flags & CONTEXT_NO_ERROR_CAPTURE);
+		args->value = i915_gem_context_no_error_capture(ctx);
 		break;
 	case I915_CONTEXT_PARAM_BANNABLE:
-		args->value = ctx->bannable;
+		args->value = i915_gem_context_is_bannable(ctx);
 		break;
 	default:
 		ret = -EINVAL;
@@ -1085,22 +1086,22 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
 		}
 		break;
 	case I915_CONTEXT_PARAM_NO_ERROR_CAPTURE:
-		if (args->size) {
+		if (args->size)
 			ret = -EINVAL;
-		} else {
-			if (args->value)
-				ctx->flags |= CONTEXT_NO_ERROR_CAPTURE;
-			else
-				ctx->flags &= ~CONTEXT_NO_ERROR_CAPTURE;
-		}
+		else if (args->value)
+			i915_gem_context_set_no_error_capture(ctx);
+		else
+			i915_gem_context_unset_no_error_capture(ctx);
 		break;
 	case I915_CONTEXT_PARAM_BANNABLE:
 		if (args->size)
 			ret = -EINVAL;
 		else if (!capable(CAP_SYS_ADMIN) && !args->value)
 			ret = -EPERM;
+		else if (args->value)
+			i915_gem_context_set_bannable(ctx);
 		else
-			ctx->bannable = args->value;
+			i915_gem_context_unset_bannable(ctx);
 		break;
 	default:
 		ret = -EINVAL;
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index c64438f8171c..a5fe299da1d3 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1238,7 +1238,7 @@ i915_gem_validate_context(struct drm_device *dev, struct drm_file *file,
 	if (IS_ERR(ctx))
 		return ctx;
 
-	if (ctx->banned) {
+	if (i915_gem_context_is_banned(ctx)) {
 		DRM_DEBUG("Context %u tried to submit while banned\n", ctx_id);
 		return ERR_PTR(-EIO);
 	}
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index e16037d1b0ba..e34532d98004 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -1331,7 +1331,7 @@ static void i915_gem_record_rings(struct drm_i915_private *dev_priv,
 			}
 
 			error->simulated |=
-				request->ctx->flags & CONTEXT_NO_ERROR_CAPTURE;
+				i915_gem_context_no_error_capture(request->ctx);
 
 			ee->rq_head = request->head;
 			ee->rq_post = request->postfix;
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index fc64be1bdea7..227978820320 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -413,7 +413,7 @@ static void execlists_submit_ports(struct intel_engine_cs *engine)
 static bool ctx_single_port_submission(const struct i915_gem_context *ctx)
 {
 	return (IS_ENABLED(CONFIG_DRM_I915_GVT) &&
-		ctx->execlists_force_single_submission);
+		i915_gem_context_force_single_submission(ctx));
 }
 
 static bool can_merge_ctx(const struct i915_gem_context *prev,
-- 
2.11.0



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