diff mbox

[v2,2/5] drm/i915: Use batch pools with the command parser

Message ID 1404858400-18879-3-git-send-email-bradley.d.volkin@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

bradley.d.volkin@intel.com July 8, 2014, 10:26 p.m. UTC 
From: Brad Volkin <bradley.d.volkin@intel.com>

This patch sets up all of the tracking and copying necessary to
use batch pools with the command parser, but does not actually
dispatch the copied (shadow) batch to the hardware yet. We still
aren't quite ready to set the secure bit during dispatch.

Note that performance takes a hit from the copy in some cases
and will likely need some work. At a rough pass, the memcpy
appears to be the bottleneck. Without having done a deeper
analysis, two ideas that come to mind are:
1) Copy sections of the batch at a time, as they are reached
   by parsing. Might improve cache locality.
2) Copy only up to the userspace-supplied batch length and
   memset the rest of the buffer. Reduces the number of reads.

v2:
- Remove setting the capacity of the pool
- One global pool instead of per-ring pools
- Replace batch_obj with shadow_batch_obj and hook into eb->vmas
- Memset any space in the shadow batch beyond what gets copied
- Rebased on execlist prep refactoring

Signed-off-by: Brad Volkin <bradley.d.volkin@intel.com>
---
 drivers/gpu/drm/i915/i915_cmd_parser.c     | 84 ++++++++++++++++++++++++------
 drivers/gpu/drm/i915/i915_dma.c            |  1 +
 drivers/gpu/drm/i915/i915_drv.h            |  8 +++
 drivers/gpu/drm/i915/i915_gem.c            |  9 ++++
 drivers/gpu/drm/i915/i915_gem_execbuffer.c | 35 +++++++++++++
 5 files changed, 121 insertions(+), 16 deletions(-)
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
index dea99d9..18788df 100644
--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -831,6 +831,56 @@  finish:
 	return (u32*)addr;
 }
 
+/* Returns a vmap'd pointer to dest_obj, which the caller must unmap */
+static u32 *copy_batch(struct drm_i915_gem_object *dest_obj,
+		       struct drm_i915_gem_object *src_obj)
+{
+	int ret = 0;
+	int needs_clflush = 0;
+	u32 *src_addr, *dest_addr = NULL;
+
+	ret = i915_gem_obj_prepare_shmem_read(src_obj, &needs_clflush);
+	if (ret) {
+		DRM_DEBUG_DRIVER("CMD: failed to prep read\n");
+		return ERR_PTR(ret);
+	}
+
+	src_addr = vmap_batch(src_obj);
+	if (!src_addr) {
+		DRM_DEBUG_DRIVER("CMD: Failed to vmap batch\n");
+		ret = -ENOMEM;
+		goto unpin_src;
+	}
+
+	if (needs_clflush)
+		drm_clflush_virt_range((char *)src_addr, src_obj->base.size);
+
+	ret = i915_gem_object_set_to_cpu_domain(dest_obj, true);
+	if (ret) {
+		DRM_DEBUG_DRIVER("CMD: Failed to set batch CPU domain\n");
+		goto unmap_src;
+	}
+
+	dest_addr = vmap_batch(dest_obj);
+	if (!dest_addr) {
+		DRM_DEBUG_DRIVER("CMD: Failed to vmap shadow batch\n");
+		ret = -ENOMEM;
+		goto unmap_src;
+	}
+
+	memcpy(dest_addr, src_addr, src_obj->base.size);
+	if (dest_obj->base.size > src_obj->base.size)
+		memset((u8 *)dest_addr + src_obj->base.size, 0,
+		       dest_obj->base.size - src_obj->base.size);
+
+unmap_src:
+	vunmap(src_addr);
+unpin_src:
+	i915_gem_object_unpin_pages(src_obj);
+
+	return ret ? ERR_PTR(ret) : dest_addr;
+}
+
 /**
  * i915_needs_cmd_parser() - should a given ring use software command parsing?
  * @ring: the ring in question
@@ -952,6 +1002,7 @@  static bool check_cmd(const struct intel_engine_cs *ring,
  * i915_parse_cmds() - parse a submitted batch buffer for privilege violations
  * @ring: the ring on which the batch is to execute
  * @batch_obj: the batch buffer in question
+ * @shadow_batch_obj: copy of the batch buffer in question
  * @batch_start_offset: byte offset in the batch at which execution starts
  * @is_master: is the submitting process the drm master?
  *
@@ -962,32 +1013,28 @@  static bool check_cmd(const struct intel_engine_cs *ring,
  */
 int i915_parse_cmds(struct intel_engine_cs *ring,
 		    struct drm_i915_gem_object *batch_obj,
+		    struct drm_i915_gem_object *shadow_batch_obj,
 		    u32 batch_start_offset,
 		    bool is_master)
 {
 	int ret = 0;
 	u32 *cmd, *batch_base, *batch_end;
 	struct drm_i915_cmd_descriptor default_desc = { 0 };
-	int needs_clflush = 0;
 	bool oacontrol_set = false; /* OACONTROL tracking. See check_cmd() */
 
-	ret = i915_gem_obj_prepare_shmem_read(batch_obj, &needs_clflush);
-	if (ret) {
-		DRM_DEBUG_DRIVER("CMD: failed to prep read\n");
-		return ret;
+	batch_base = copy_batch(shadow_batch_obj, batch_obj);
+	if (IS_ERR(batch_base)) {
+		DRM_DEBUG_DRIVER("CMD: Failed to copy batch\n");
+		return PTR_ERR(batch_base);
 	}
 
-	batch_base = vmap_batch(batch_obj);
-	if (!batch_base) {
-		DRM_DEBUG_DRIVER("CMD: Failed to vmap batch\n");
-		i915_gem_object_unpin_pages(batch_obj);
-		return -ENOMEM;
-	}
-
-	if (needs_clflush)
-		drm_clflush_virt_range((char *)batch_base, batch_obj->base.size);
-
 	cmd = batch_base + (batch_start_offset / sizeof(*cmd));
+
+	/*
+	 * We use the source object's size because the shadow object is as
+	 * large or larger and copy_batch() will write MI_NOPs to the extra
+	 * space. Parsing should be faster in some cases this way.
+	 */
 	batch_end = cmd + (batch_obj->base.size / sizeof(*batch_end));
 
 	while (cmd < batch_end) {
@@ -1039,7 +1086,12 @@  int i915_parse_cmds(struct intel_engine_cs *ring,
 
 	vunmap(batch_base);
 
-	i915_gem_object_unpin_pages(batch_obj);
+	if (!ret) {
+		ret = i915_gem_object_set_to_gtt_domain(shadow_batch_obj,
+							false);
+		if (ret)
+			DRM_DEBUG_DRIVER("CMD: Failed to set batch GTT domain\n");
+	}
 
 	return ret;
 }
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 0266dad..8b994f1 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1877,6 +1877,7 @@  int i915_driver_unload(struct drm_device *dev)
 
 		mutex_lock(&dev->struct_mutex);
 		i915_gem_cleanup_ringbuffer(dev);
+		i915_gem_batch_pool_fini(&dev_priv->mm.batch_pool);
 		i915_gem_context_fini(dev);
 		WARN_ON(dev_priv->mm.aliasing_ppgtt);
 		mutex_unlock(&dev->struct_mutex);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a478a96..a6b903d 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1081,6 +1081,13 @@  struct i915_gem_mm {
 	 */
 	struct list_head unbound_list;
 
+	/*
+	 * A pool of objects to use as shadow copies of client batch buffers
+	 * when the command parser is enabled. Prevents the client from
+	 * modifying the batch contents after software parsing.
+	 */
+	struct i915_gem_batch_pool batch_pool;
+
 	/** Usable portion of the GTT for GEM */
 	unsigned long stolen_base; /* limited to low memory (32-bit) */
 
@@ -2618,6 +2625,7 @@  void i915_cmd_parser_fini_ring(struct intel_engine_cs *ring);
 bool i915_needs_cmd_parser(struct intel_engine_cs *ring);
 int i915_parse_cmds(struct intel_engine_cs *ring,
 		    struct drm_i915_gem_object *batch_obj,
+		    struct drm_i915_gem_object *shadow_batch_obj,
 		    u32 batch_start_offset,
 		    bool is_master);
 
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 89a4ec0..a4b789b 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2476,6 +2476,13 @@  static void i915_gem_free_request(struct drm_i915_gem_request *request)
 	if (request->ctx)
 		i915_gem_context_unreference(request->ctx);
 
+	if (!list_empty(&request->batch_obj->batch_pool_list)) {
+		struct drm_i915_private *dev_priv = to_i915(request->ring->dev);
+
+		i915_gem_batch_pool_put(&dev_priv->mm.batch_pool,
+					request->batch_obj);
+	}
+
 	kfree(request);
 }
 
@@ -4947,6 +4954,8 @@  i915_gem_load(struct drm_device *dev)
 	dev_priv->mm.oom_notifier.notifier_call = i915_gem_shrinker_oom;
 	register_oom_notifier(&dev_priv->mm.oom_notifier);
 
+	i915_gem_batch_pool_init(dev, &dev_priv->mm.batch_pool);
+
 	mutex_init(&dev_priv->fb_tracking.lock);
 }
 
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 60998fc..4c4bd66 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1242,6 +1242,8 @@  i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct eb_vmas *eb;
 	struct drm_i915_gem_object *batch_obj;
+	struct drm_i915_gem_object *shadow_batch_obj = NULL;
+	struct drm_i915_gem_exec_object2 shadow_exec_entry;
 	struct intel_engine_cs *ring;
 	struct intel_context *ctx;
 	struct i915_address_space *vm;
@@ -1366,13 +1368,38 @@  i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 	batch_obj->base.pending_read_domains |= I915_GEM_DOMAIN_COMMAND;
 
 	if (i915_needs_cmd_parser(ring)) {
+		struct i915_vma *vma;
+
+		shadow_batch_obj =
+			i915_gem_batch_pool_get(&dev_priv->mm.batch_pool,
+						batch_obj->base.size);
+		if (IS_ERR(shadow_batch_obj)) {
+			ret = PTR_ERR(shadow_batch_obj);
+			/* Don't try to clean up the obj in the error path */
+			shadow_batch_obj = NULL;
+			goto err;
+		}
+
+		ret = i915_gem_obj_ggtt_pin(shadow_batch_obj, 4096, 0);
+		if (ret)
+			goto err;
+
 		ret = i915_parse_cmds(ring,
 				      batch_obj,
+				      shadow_batch_obj,
 				      args->batch_start_offset,
 				      file->is_master);
 		if (ret)
 			goto err;
 
+		vma = i915_gem_obj_to_ggtt(shadow_batch_obj);
+		vma->exec_entry = &shadow_exec_entry;
+		vma->exec_entry->flags = __EXEC_OBJECT_HAS_PIN;
+		drm_gem_object_reference(&shadow_batch_obj->base);
+		list_add_tail(&vma->exec_list, &eb->vmas);
+
+		batch_obj = shadow_batch_obj;
+
 		/*
 		 * XXX: Actually do this when enabling batch copy...
 		 *
@@ -1410,6 +1437,14 @@  err:
 	i915_gem_context_unreference(ctx);
 	eb_destroy(eb);
 
+	if (ret && ring && shadow_batch_obj) {
+		if (i915_gem_obj_is_pinned(shadow_batch_obj))
+			i915_gem_object_ggtt_unpin(shadow_batch_obj);
+
+		i915_gem_batch_pool_put(&dev_priv->mm.batch_pool,
+					shadow_batch_obj);
+	}
+
 	mutex_unlock(&dev->struct_mutex);
 
 pre_mutex_err: