-----Original Message-----
From: Nguyen, Michael H
Sent: Wednesday, November 26, 2014 9:54 PM
To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Bloomfield, Jon; Volkin, Bradley D
Subject: [PATCH v5 1/7] drm/i915: Implement a framework for batch buffer
pools
From: Brad Volkin <bradley.d.volkin@xxxxxxxxx>
This adds a small module for managing a pool of batch buffers.
The only current use case is for the command parser, as described in the
kerneldoc in the patch. The code is simple, but separating it out makes it
easier to change the underlying algorithms and to extend to future use cases
should they arise.
The interface is simple: init to create an empty pool, fini to clean it up, get to
obtain a new buffer. Note that all buffers are expected to be inactive before
cleaning up the pool.
Locking is currently based on the caller holding the struct_mutex.
We already do that in the places where we will use the batch pool for the
command parser.
v2:
- s/BUG_ON/WARN_ON/ for locking assertions
- Remove the cap on pool size
- Switch from alloc/free to init/fini
v3:
- Idiomatic looping structure in _fini
- Correct handling of purged objects
- Don't return a buffer that's too much larger than needed
v4:
- Rebased to latest -nightly
v5:
- Remove _put() function and clean up comments to match
v6:
- Move purged check inside the loop (danvet, from v4 1/7 feedback)
Issue: VIZ-4719
Signed-off-by: Brad Volkin <bradley.d.volkin@xxxxxxxxx>
---
Documentation/DocBook/drm.tmpl | 5 +
drivers/gpu/drm/i915/Makefile | 1 +
drivers/gpu/drm/i915/i915_drv.h | 15 +++
drivers/gpu/drm/i915/i915_gem.c | 1 +
drivers/gpu/drm/i915/i915_gem_batch_pool.c | 152
+++++++++++++++++++++++++++++
5 files changed, 174 insertions(+)
create mode 100644 drivers/gpu/drm/i915/i915_gem_batch_pool.c
diff --git a/Documentation/DocBook/drm.tmpl
b/Documentation/DocBook/drm.tmpl index 944e8ed..b5943d4 100644
--- a/Documentation/DocBook/drm.tmpl
+++ b/Documentation/DocBook/drm.tmpl
@@ -4028,6 +4028,11 @@ int num_ioctls;</synopsis>
!Idrivers/gpu/drm/i915/i915_cmd_parser.c
</sect2>
<sect2>
+ <title>Batchbuffer Pools</title>
+!Pdrivers/gpu/drm/i915/i915_gem_batch_pool.c batch pool
+!Idrivers/gpu/drm/i915/i915_gem_batch_pool.c
+ </sect2>
+ <sect2>
<title>Logical Rings, Logical Ring Contexts and Execlists</title>
!Pdrivers/gpu/drm/i915/intel_lrc.c Logical Rings, Logical Ring Contexts and
Execlists !Idrivers/gpu/drm/i915/intel_lrc.c
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index e4083e4..c8dbb37d 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -19,6 +19,7 @@ i915-$(CONFIG_DEBUG_FS) += i915_debugfs.o
# GEM code
i915-y += i915_cmd_parser.o \
+ i915_gem_batch_pool.o \
i915_gem_context.o \
i915_gem_render_state.o \
i915_gem_debug.o \
diff --git a/drivers/gpu/drm/i915/i915_drv.h
b/drivers/gpu/drm/i915/i915_drv.h index c4f2cb6..b12a062 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1154,6 +1154,12 @@ struct intel_l3_parity {
int which_slice;
};
+struct i915_gem_batch_pool {
+ struct drm_device *dev;
+ struct list_head active_list;
+ struct list_head inactive_list;
+};
+
struct i915_gem_mm {
/** Memory allocator for GTT stolen memory */
struct drm_mm stolen;
@@ -1885,6 +1891,8 @@ struct drm_i915_gem_object {
/** Used in execbuf to temporarily hold a ref */
struct list_head obj_exec_link;
+ struct list_head batch_pool_list;
+
/**
* This is set if the object is on the active lists (has pending
* rendering and so a non-zero seqno), and is not set if it i s on @@ -
2849,6 +2857,13 @@ void i915_destroy_error_state(struct drm_device
*dev); void i915_get_extra_instdone(struct drm_device *dev, uint32_t
*instdone); const char *i915_cache_level_str(struct drm_i915_private *i915,
int type);
+/* i915_gem_batch_pool.c */
+void i915_gem_batch_pool_init(struct drm_device *dev,
+ struct i915_gem_batch_pool *pool); void
+i915_gem_batch_pool_fini(struct i915_gem_batch_pool *pool); struct
+drm_i915_gem_object* i915_gem_batch_pool_get(struct
i915_gem_batch_pool
+*pool, size_t size);
+
/* i915_cmd_parser.c */
int i915_cmd_parser_get_version(void);
int i915_cmd_parser_init_ring(struct intel_engine_cs *ring); diff --git
a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 86cf428..b19dd06 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4433,6 +4433,7 @@ void i915_gem_object_init(struct
drm_i915_gem_object *obj,
INIT_LIST_HEAD(&obj->ring_list);
INIT_LIST_HEAD(&obj->obj_exec_link);
INIT_LIST_HEAD(&obj->vma_list);
+ INIT_LIST_HEAD(&obj->batch_pool_list);
obj->ops = ops;
diff --git a/drivers/gpu/drm/i915/i915_gem_batch_pool.c
b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
new file mode 100644
index 0000000..ccbe8f9
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
@@ -0,0 +1,152 @@
+/*
+ * Copyright © 2014 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person
+obtaining a
+ * copy of this software and associated documentation files (the
+"Software"),
+ * to deal in the Software without restriction, including without
+limitation
+ * the rights to use, copy, modify, merge, publish, distribute,
+sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom
+the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+next
+ * paragraph) shall be included in all copies or substantial portions
+of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO
EVENT
+SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
DAMAGES OR
+OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER
+DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include "i915_drv.h"
+
+/**
+ * DOC: batch pool
+ *
+ * In order to submit batch buffers as 'secure', the software command
+parser
+ * must ensure that a batch buffer cannot be modified after parsing. It
+does
+ * this by copying the user provided batch buffer contents to a kernel
+owned
+ * buffer from which the hardware will actually execute, and by
+carefully
+ * managing the address space bindings for such buffers.
+ *
+ * The batch pool framework provides a mechanism for the driver to
+manage a
+ * set of scratch buffers to use for this purpose. The framework can be
+ * extended to support other uses cases should they arise.
+ */
+
+/**
+ * i915_gem_batch_pool_init() - initialize a batch buffer pool
+ * @dev: the drm device
+ * @pool: the batch buffer pool
+ */
+void i915_gem_batch_pool_init(struct drm_device *dev,
+ struct i915_gem_batch_pool *pool) {
+ pool->dev = dev;
+ INIT_LIST_HEAD(&pool->active_list);
+ INIT_LIST_HEAD(&pool->inactive_list);
+}
+
+/**
+ * i915_gem_batch_pool_fini() - clean up a batch buffer pool
+ * @pool: the pool to clean up
+ *
+ * Note: Callers must hold the struct_mutex.
+ */
+void i915_gem_batch_pool_fini(struct i915_gem_batch_pool *pool) {
+ WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex));
+
+ while (!list_empty(&pool->active_list)) {
+ struct drm_i915_gem_object *obj =
+ list_first_entry(&pool->active_list,
+ struct drm_i915_gem_object,
+ batch_pool_list);
+
+ WARN_ON(obj->active);
+
+ list_del_init(&obj->batch_pool_list);
+ drm_gem_object_unreference(&obj->base);
+ }
+
+ while (!list_empty(&pool->inactive_list)) {
+ struct drm_i915_gem_object *obj =
+ list_first_entry(&pool->inactive_list,
+ struct drm_i915_gem_object,
+ batch_pool_list);
+
+ list_del_init(&obj->batch_pool_list);
+ drm_gem_object_unreference(&obj->base);
+ }
+}
+
+/**
+ * i915_gem_batch_pool_get() - select a buffer from the pool
+ * @pool: the batch buffer pool
+ * @size: the minimum desired size of the returned buffer
+ *
+ * Finds or allocates a batch buffer in the pool with at least the
+requested
+ * size. The caller is responsible for any domain, active/inactive, or
+ * purgeability management for the returned buffer.
+ *
+ * Note: Callers must hold the struct_mutex
+ *
+ * Return: the selected batch buffer object */ struct
+drm_i915_gem_object * i915_gem_batch_pool_get(struct
+i915_gem_batch_pool *pool,
+ size_t size)
+{
+ struct drm_i915_gem_object *obj = NULL;
+ struct drm_i915_gem_object *tmp, *next;
+ bool was_purged;
+
+ WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex));
+
+ list_for_each_entry_safe(tmp, next,
+ &pool->active_list, batch_pool_list) {
+ if (!tmp->active)
+ list_move_tail(&tmp->batch_pool_list,
+ &pool->inactive_list);
+ }
+
+ do {
+ was_purged = false;
+
+ list_for_each_entry_safe(tmp, next,
+ &pool->inactive_list, batch_pool_list) {
+ /*
+ * Select a buffer that is at least as big as needed
+ * but not 'too much' bigger. A better way to do this
+ * might be to bucket the pool objects based on size.
+ */
+ if (tmp->base.size >= size &&
+ tmp->base.size <= (2 * size)) {
+ obj = tmp;
+ break;
+ }
+
+ if (tmp->madv == __I915_MADV_PURGED) {
+ was_purged = true;
+ list_del(&tmp->batch_pool_list);
+ drm_gem_object_unreference(&tmp-
base);
+ }
+ }
+ } while (was_purged);
