[v6,1/5] drm/i915: Implement a framework for batch buffer pools

Commit Message

Michael H. Nguyen Dec. 8, 2014, 10:33 p.m. UTC

From: Brad Volkin <[e-mail]>

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)

v7:
- Use single list instead of two. (Chris W)
- s/active_list/cache_list
- Squashed in debug patches (Chris W)
  drm/i915: Add a batch pool debugfs file

  It provides some useful information about the buffers in
  the global command parser batch pool.

  v2: rebase on global pool instead of per-ring pools
  v3: rebase

  drm/i915: Add batch pool details to i915_gem_objects debugfs

  To better account for the potentially large memory consumption
  of the batch pool.

Issue: VIZ-4719
Signed-off-by: Brad Volkin <[e-mail]>
---
 Documentation/DocBook/drm.tmpl             |   5 ++
 drivers/gpu/drm/i915/Makefile              |   1 +
 drivers/gpu/drm/i915/i915_debugfs.c        |  71 ++++++++++++++--
 drivers/gpu/drm/i915/i915_drv.h            |  21 +++++
 drivers/gpu/drm/i915/i915_gem.c            |   1 +
 drivers/gpu/drm/i915/i915_gem_batch_pool.c | 132 +++++++++++++++++++++++++++++
 6 files changed, 222 insertions(+), 9 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/i915_gem_batch_pool.c

Comments

Daniel Vetter Dec. 9, 2014, 1:18 p.m. UTC | #1

On Mon, Dec 08, 2014 at 02:33:46PM -0800, [e-mail] wrote:
> From: Brad Volkin <[e-mail]>
> 
> 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)
> 
> v7:
> - Use single list instead of two. (Chris W)
> - s/active_list/cache_list
> - Squashed in debug patches (Chris W)
>   drm/i915: Add a batch pool debugfs file
> 
>   It provides some useful information about the buffers in
>   the global command parser batch pool.
> 
>   v2: rebase on global pool instead of per-ring pools
>   v3: rebase
> 
>   drm/i915: Add batch pool details to i915_gem_objects debugfs
> 
>   To better account for the potentially large memory consumption
>   of the batch pool.
> 
> Issue: VIZ-4719
> Signed-off-by: Brad Volkin <[e-mail]>
> ---
>  Documentation/DocBook/drm.tmpl             |   5 ++
>  drivers/gpu/drm/i915/Makefile              |   1 +
>  drivers/gpu/drm/i915/i915_debugfs.c        |  71 ++++++++++++++--
>  drivers/gpu/drm/i915/i915_drv.h            |  21 +++++
>  drivers/gpu/drm/i915/i915_gem.c            |   1 +
>  drivers/gpu/drm/i915/i915_gem_batch_pool.c | 132 +++++++++++++++++++++++++++++
>  6 files changed, 222 insertions(+), 9 deletions(-)
>  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 85287cb..022923a 100644
> --- a/Documentation/DocBook/drm.tmpl
> +++ b/Documentation/DocBook/drm.tmpl
> @@ -4029,6 +4029,11 @@ 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_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index d0e445e..3c3bf98 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -359,6 +359,33 @@ static int per_file_stats(int id, void *ptr, void *data)
>  	return 0;
>  }
>  
> +#define print_file_stats(m, name, stats) \
> +	seq_printf(m, "%s: %u objects, %zu bytes (%zu active, %zu inactive, %zu global, %zu shared, %zu unbound)\n", \
> +		   name, \
> +		   stats.count, \
> +		   stats.total, \
> +		   stats.active, \
> +		   stats.inactive, \
> +		   stats.global, \
> +		   stats.shared, \
> +		   stats.unbound)
> +
> +static void print_batch_pool_stats(struct seq_file *m,
> +				   struct drm_i915_private *dev_priv)
> +{
> +	struct drm_i915_gem_object *obj;
> +	struct file_stats stats;
> +
> +	memset(&stats, 0, sizeof(stats));
> +
> +	list_for_each_entry(obj,
> +			    &dev_priv->mm.batch_pool.cache_list,
> +			    batch_pool_list)
> +		per_file_stats(0, obj, &stats);
> +
> +	print_file_stats(m, "batch pool", stats);
> +}
> +
>  #define count_vmas(list, member) do { \
>  	list_for_each_entry(vma, list, member) { \
>  		size += i915_gem_obj_ggtt_size(vma->obj); \
> @@ -441,6 +468,9 @@ static int i915_gem_object_info(struct seq_file *m, void* data)
>  		   dev_priv->gtt.mappable_end - dev_priv->gtt.base.start);
>  
>  	seq_putc(m, '\n');
> +	print_batch_pool_stats(m, dev_priv);
> +
> +	seq_putc(m, '\n');
>  	list_for_each_entry_reverse(file, &dev->filelist, lhead) {
>  		struct file_stats stats;
>  		struct task_struct *task;
> @@ -458,15 +488,7 @@ static int i915_gem_object_info(struct seq_file *m, void* data)
>  		 */
>  		rcu_read_lock();
>  		task = pid_task(file->pid, PIDTYPE_PID);
> -		seq_printf(m, "%s: %u objects, %zu bytes (%zu active, %zu inactive, %zu global, %zu shared, %zu unbound)\n",
> -			   task ? task->comm : "<unknown>",
> -			   stats.count,
> -			   stats.total,
> -			   stats.active,
> -			   stats.inactive,
> -			   stats.global,
> -			   stats.shared,
> -			   stats.unbound);
> +		print_file_stats(m, task ? task->comm : "<unknown>", stats);
>  		rcu_read_unlock();
>  	}
>  
> @@ -583,6 +605,36 @@ static int i915_gem_pageflip_info(struct seq_file *m, void *data)
>  	return 0;
>  }
>  
> +static int i915_gem_batch_pool_info(struct seq_file *m, void *data)
> +{
> +	struct drm_info_node *node = m->private;
> +	struct drm_device *dev = node->minor->dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct drm_i915_gem_object *obj;
> +	int count = 0;
> +	int ret;
> +
> +	ret = mutex_lock_interruptible(&dev->struct_mutex);
> +	if (ret)
> +		return ret;
> +
> +	seq_puts(m, "cache:\n");
> +	list_for_each_entry(obj,
> +			    &dev_priv->mm.batch_pool.cache_list,
> +			    batch_pool_list) {
> +		seq_puts(m, "   ");
> +		describe_obj(m, obj);
> +		seq_putc(m, '\n');
> +		count++;
> +	}
> +
> +	seq_printf(m, "total: %d\n", count);
> +
> +	mutex_unlock(&dev->struct_mutex);
> +
> +	return 0;
> +}
> +
>  static int i915_gem_request_info(struct seq_file *m, void *data)
>  {
>  	struct drm_info_node *node = m->private;
> @@ -4324,6 +4376,7 @@ static const struct drm_info_list i915_debugfs_list[] = {
>  	{"i915_gem_hws_blt", i915_hws_info, 0, (void *)BCS},
>  	{"i915_gem_hws_bsd", i915_hws_info, 0, (void *)VCS},
>  	{"i915_gem_hws_vebox", i915_hws_info, 0, (void *)VECS},
> +	{"i915_gem_batch_pool", i915_gem_batch_pool_info, 0},
>  	{"i915_frequency_info", i915_frequency_info, 0},
>  	{"i915_drpc_info", i915_drpc_info, 0},
>  	{"i915_emon_status", i915_emon_status, 0},
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 11e85cb..f3e27e9 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1129,6 +1129,11 @@ struct intel_l3_parity {
>  	int which_slice;
>  };
>  
> +struct i915_gem_batch_pool {
> +	struct drm_device *dev;
> +	struct list_head cache_list;
> +};
> +
>  struct i915_gem_mm {
>  	/** Memory allocator for GTT stolen memory */
>  	struct drm_mm stolen;
> @@ -1142,6 +1147,13 @@ 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) */
>  
> @@ -1872,6 +1884,8 @@ 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
> @@ -2876,6 +2890,13 @@ 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 de241eb..2f14ae1 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -4384,6 +4384,7 @@ 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..e9349e3
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
> @@ -0,0 +1,132 @@
> +/*
> + * 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->cache_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->cache_list)) {
> +		struct drm_i915_gem_object *obj =
> +			list_first_entry(&pool->cache_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);
> +	}
> +}
> +
> +/**
> + * 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;
> +
> +	WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex));
> +
> +	list_for_each_entry_safe(tmp, next,
> +			&pool->cache_list, batch_pool_list) {
> +
> +		if (tmp->active)
> +			continue;
> +
> +		/* While we're looping, do some clean up */
> +		if (tmp->madv == __I915_MADV_PURGED) {
> +			list_del(&tmp->batch_pool_list);
> +			drm_gem_object_unreference(&tmp->base);
> +			continue;
> +		}
> +
> +		/*
> +		 * 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 (!obj) {
> +		obj = i915_gem_alloc_object(pool->dev, size);
> +		if (!obj)
> +			return ERR_PTR(-ENOMEM);
> +
> +		list_add_tail(&obj->batch_pool_list, &pool->cache_list);
> +	}

Shouldn't we have a else list_move_tail here to keep the list in lru
order?
-Daniel

> +
> +	return obj;
> +}
> -- 
> 1.9.1
> 
> _______________________________________________
> Intel-gfx mailing list
> [e-mail]
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

Michael H. Nguyen Dec. 9, 2014, 7:42 p.m. UTC | #2

On 12/09/2014 05:18 AM, Daniel Vetter wrote:
> On Mon, Dec 08, 2014 at 02:33:46PM -0800, [e-mail] wrote:
>> From: Brad Volkin <[e-mail]>
>>
>> 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)
>>
>> v7:
>> - Use single list instead of two. (Chris W)
>> - s/active_list/cache_list
>> - Squashed in debug patches (Chris W)
>>    drm/i915: Add a batch pool debugfs file
>>
>>    It provides some useful information about the buffers in
>>    the global command parser batch pool.
>>
>>    v2: rebase on global pool instead of per-ring pools
>>    v3: rebase
>>
>>    drm/i915: Add batch pool details to i915_gem_objects debugfs
>>
>>    To better account for the potentially large memory consumption
>>    of the batch pool.
>>
>> Issue: VIZ-4719
>> Signed-off-by: Brad Volkin <[e-mail]>
>> ---
>>   Documentation/DocBook/drm.tmpl             |   5 ++
>>   drivers/gpu/drm/i915/Makefile              |   1 +
>>   drivers/gpu/drm/i915/i915_debugfs.c        |  71 ++++++++++++++--
>>   drivers/gpu/drm/i915/i915_drv.h            |  21 +++++
>>   drivers/gpu/drm/i915/i915_gem.c            |   1 +
>>   drivers/gpu/drm/i915/i915_gem_batch_pool.c | 132 +++++++++++++++++++++++++++++
>>   6 files changed, 222 insertions(+), 9 deletions(-)
>>   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 85287cb..022923a 100644
>> --- a/Documentation/DocBook/drm.tmpl
>> +++ b/Documentation/DocBook/drm.tmpl
>> @@ -4029,6 +4029,11 @@ 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_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
>> index d0e445e..3c3bf98 100644
>> --- a/drivers/gpu/drm/i915/i915_debugfs.c
>> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
>> @@ -359,6 +359,33 @@ static int per_file_stats(int id, void *ptr, void *data)
>>   	return 0;
>>   }
>>
>> +#define print_file_stats(m, name, stats) \
>> +	seq_printf(m, "%s: %u objects, %zu bytes (%zu active, %zu inactive, %zu global, %zu shared, %zu unbound)\n", \
>> +		   name, \
>> +		   stats.count, \
>> +		   stats.total, \
>> +		   stats.active, \
>> +		   stats.inactive, \
>> +		   stats.global, \
>> +		   stats.shared, \
>> +		   stats.unbound)
>> +
>> +static void print_batch_pool_stats(struct seq_file *m,
>> +				   struct drm_i915_private *dev_priv)
>> +{
>> +	struct drm_i915_gem_object *obj;
>> +	struct file_stats stats;
>> +
>> +	memset(&stats, 0, sizeof(stats));
>> +
>> +	list_for_each_entry(obj,
>> +			    &dev_priv->mm.batch_pool.cache_list,
>> +			    batch_pool_list)
>> +		per_file_stats(0, obj, &stats);
>> +
>> +	print_file_stats(m, "batch pool", stats);
>> +}
>> +
>>   #define count_vmas(list, member) do { \
>>   	list_for_each_entry(vma, list, member) { \
>>   		size += i915_gem_obj_ggtt_size(vma->obj); \
>> @@ -441,6 +468,9 @@ static int i915_gem_object_info(struct seq_file *m, void* data)
>>   		   dev_priv->gtt.mappable_end - dev_priv->gtt.base.start);
>>
>>   	seq_putc(m, '\n');
>> +	print_batch_pool_stats(m, dev_priv);
>> +
>> +	seq_putc(m, '\n');
>>   	list_for_each_entry_reverse(file, &dev->filelist, lhead) {
>>   		struct file_stats stats;
>>   		struct task_struct *task;
>> @@ -458,15 +488,7 @@ static int i915_gem_object_info(struct seq_file *m, void* data)
>>   		 */
>>   		rcu_read_lock();
>>   		task = pid_task(file->pid, PIDTYPE_PID);
>> -		seq_printf(m, "%s: %u objects, %zu bytes (%zu active, %zu inactive, %zu global, %zu shared, %zu unbound)\n",
>> -			   task ? task->comm : "<unknown>",
>> -			   stats.count,
>> -			   stats.total,
>> -			   stats.active,
>> -			   stats.inactive,
>> -			   stats.global,
>> -			   stats.shared,
>> -			   stats.unbound);
>> +		print_file_stats(m, task ? task->comm : "<unknown>", stats);
>>   		rcu_read_unlock();
>>   	}
>>
>> @@ -583,6 +605,36 @@ static int i915_gem_pageflip_info(struct seq_file *m, void *data)
>>   	return 0;
>>   }
>>
>> +static int i915_gem_batch_pool_info(struct seq_file *m, void *data)
>> +{
>> +	struct drm_info_node *node = m->private;
>> +	struct drm_device *dev = node->minor->dev;
>> +	struct drm_i915_private *dev_priv = dev->dev_private;
>> +	struct drm_i915_gem_object *obj;
>> +	int count = 0;
>> +	int ret;
>> +
>> +	ret = mutex_lock_interruptible(&dev->struct_mutex);
>> +	if (ret)
>> +		return ret;
>> +
>> +	seq_puts(m, "cache:\n");
>> +	list_for_each_entry(obj,
>> +			    &dev_priv->mm.batch_pool.cache_list,
>> +			    batch_pool_list) {
>> +		seq_puts(m, "   ");
>> +		describe_obj(m, obj);
>> +		seq_putc(m, '\n');
>> +		count++;
>> +	}
>> +
>> +	seq_printf(m, "total: %d\n", count);
>> +
>> +	mutex_unlock(&dev->struct_mutex);
>> +
>> +	return 0;
>> +}
>> +
>>   static int i915_gem_request_info(struct seq_file *m, void *data)
>>   {
>>   	struct drm_info_node *node = m->private;
>> @@ -4324,6 +4376,7 @@ static const struct drm_info_list i915_debugfs_list[] = {
>>   	{"i915_gem_hws_blt", i915_hws_info, 0, (void *)BCS},
>>   	{"i915_gem_hws_bsd", i915_hws_info, 0, (void *)VCS},
>>   	{"i915_gem_hws_vebox", i915_hws_info, 0, (void *)VECS},
>> +	{"i915_gem_batch_pool", i915_gem_batch_pool_info, 0},
>>   	{"i915_frequency_info", i915_frequency_info, 0},
>>   	{"i915_drpc_info", i915_drpc_info, 0},
>>   	{"i915_emon_status", i915_emon_status, 0},
>> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>> index 11e85cb..f3e27e9 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.h
>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>> @@ -1129,6 +1129,11 @@ struct intel_l3_parity {
>>   	int which_slice;
>>   };
>>
>> +struct i915_gem_batch_pool {
>> +	struct drm_device *dev;
>> +	struct list_head cache_list;
>> +};
>> +
>>   struct i915_gem_mm {
>>   	/** Memory allocator for GTT stolen memory */
>>   	struct drm_mm stolen;
>> @@ -1142,6 +1147,13 @@ 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) */
>>
>> @@ -1872,6 +1884,8 @@ 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
>> @@ -2876,6 +2890,13 @@ 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 de241eb..2f14ae1 100644
>> --- a/drivers/gpu/drm/i915/i915_gem.c
>> +++ b/drivers/gpu/drm/i915/i915_gem.c
>> @@ -4384,6 +4384,7 @@ 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..e9349e3
>> --- /dev/null
>> +++ b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
>> @@ -0,0 +1,132 @@
>> +/*
>> + * 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->cache_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->cache_list)) {
>> +		struct drm_i915_gem_object *obj =
>> +			list_first_entry(&pool->cache_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);
>> +	}
>> +}
>> +
>> +/**
>> + * 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;
>> +
>> +	WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex));
>> +
>> +	list_for_each_entry_safe(tmp, next,
>> +			&pool->cache_list, batch_pool_list) {
>> +
>> +		if (tmp->active)
>> +			continue;
>> +
>> +		/* While we're looping, do some clean up */
>> +		if (tmp->madv == __I915_MADV_PURGED) {
>> +			list_del(&tmp->batch_pool_list);
>> +			drm_gem_object_unreference(&tmp->base);
>> +			continue;
>> +		}
>> +
>> +		/*
>> +		 * 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 (!obj) {
>> +		obj = i915_gem_alloc_object(pool->dev, size);
>> +		if (!obj)
>> +			return ERR_PTR(-ENOMEM);
>> +
>> +		list_add_tail(&obj->batch_pool_list, &pool->cache_list);
>> +	}
>
> Shouldn't we have a else list_move_tail here to keep the list in lru
> order?
Yes!
> -Daniel
>
>> +
>> +	return obj;
>> +}
>> --
>> 1.9.1
>>
>> _______________________________________________
>> Intel-gfx mailing list
>> [e-mail]
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>

Bloomfield, Jon Dec. 10, 2014, 11:06 a.m. UTC | #3

> -----Original Message-----

> From: Intel-gfx [mailto:[e-mail]] On Behalf

> Of Daniel Vetter

> Sent: Tuesday, December 09, 2014 1:18 PM

> To: Nguyen, Michael H

> Cc: Brad Volkin; [e-mail]

> Subject: Re: [Intel-gfx] [PATCH v6 1/5] drm/i915: Implement a framework for

> batch buffer pools

> 

> On Mon, Dec 08, 2014 at 02:33:46PM -0800, [e-mail]

> wrote:

> > From: Brad Volkin <[e-mail]>

> >

> > 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)

> >

> > v7:

> > - Use single list instead of two. (Chris W)

> > - s/active_list/cache_list

> > - Squashed in debug patches (Chris W)

> >   drm/i915: Add a batch pool debugfs file

> >

> >   It provides some useful information about the buffers in

> >   the global command parser batch pool.

> >

> >   v2: rebase on global pool instead of per-ring pools

> >   v3: rebase

> >

> >   drm/i915: Add batch pool details to i915_gem_objects debugfs

> >

> >   To better account for the potentially large memory consumption

> >   of the batch pool.

> >

> > Issue: VIZ-4719

> > Signed-off-by: Brad Volkin <[e-mail]>

> > ---

> >  Documentation/DocBook/drm.tmpl             |   5 ++

> >  drivers/gpu/drm/i915/Makefile              |   1 +

> >  drivers/gpu/drm/i915/i915_debugfs.c        |  71 ++++++++++++++--

> >  drivers/gpu/drm/i915/i915_drv.h            |  21 +++++

> >  drivers/gpu/drm/i915/i915_gem.c            |   1 +

> >  drivers/gpu/drm/i915/i915_gem_batch_pool.c | 132

> > +++++++++++++++++++++++++++++

> >  6 files changed, 222 insertions(+), 9 deletions(-)  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 85287cb..022923a 100644

> > --- a/Documentation/DocBook/drm.tmpl

> > +++ b/Documentation/DocBook/drm.tmpl

> > @@ -4029,6 +4029,11 @@ 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_debugfs.c

> > b/drivers/gpu/drm/i915/i915_debugfs.c

> > index d0e445e..3c3bf98 100644

> > --- a/drivers/gpu/drm/i915/i915_debugfs.c

> > +++ b/drivers/gpu/drm/i915/i915_debugfs.c

> > @@ -359,6 +359,33 @@ static int per_file_stats(int id, void *ptr, void

> *data)

> >  	return 0;

> >  }

> >

> > +#define print_file_stats(m, name, stats) \

> > +	seq_printf(m, "%s: %u objects, %zu bytes (%zu active, %zu inactive,

> %zu global, %zu shared, %zu unbound)\n", \

> > +		   name, \

> > +		   stats.count, \

> > +		   stats.total, \

> > +		   stats.active, \

> > +		   stats.inactive, \

> > +		   stats.global, \

> > +		   stats.shared, \

> > +		   stats.unbound)


"print_file_stats" might be better named "print_obj_stats" or similar. As it stands
there is nothing in its name to suggest its purpose is to describe an object.


> > +

> > +static void print_batch_pool_stats(struct seq_file *m,

> > +				   struct drm_i915_private *dev_priv) {

> > +	struct drm_i915_gem_object *obj;

> > +	struct file_stats stats;

> > +

> > +	memset(&stats, 0, sizeof(stats));

> > +

> > +	list_for_each_entry(obj,

> > +			    &dev_priv->mm.batch_pool.cache_list,

> > +			    batch_pool_list)

> > +		per_file_stats(0, obj, &stats);


Shouldn't we be holding the batch_pool lock here ?


> > +

> > +	print_file_stats(m, "batch pool", stats); }

> > +

> >  #define count_vmas(list, member) do { \

> >  	list_for_each_entry(vma, list, member) { \

> >  		size += i915_gem_obj_ggtt_size(vma->obj); \ @@ -441,6

> +468,9 @@

> > static int i915_gem_object_info(struct seq_file *m, void* data)

> >  		   dev_priv->gtt.mappable_end - dev_priv->gtt.base.start);

> >

> >  	seq_putc(m, '\n');

> > +	print_batch_pool_stats(m, dev_priv);

> > +

> > +	seq_putc(m, '\n');

> >  	list_for_each_entry_reverse(file, &dev->filelist, lhead) {

> >  		struct file_stats stats;

> >  		struct task_struct *task;

> > @@ -458,15 +488,7 @@ static int i915_gem_object_info(struct seq_file *m,

> void* data)

> >  		 */

> >  		rcu_read_lock();

> >  		task = pid_task(file->pid, PIDTYPE_PID);

> > -		seq_printf(m, "%s: %u objects, %zu bytes (%zu active, %zu

> inactive, %zu global, %zu shared, %zu unbound)\n",

> > -			   task ? task->comm : "<unknown>",

> > -			   stats.count,

> > -			   stats.total,

> > -			   stats.active,

> > -			   stats.inactive,

> > -			   stats.global,

> > -			   stats.shared,

> > -			   stats.unbound);

> > +		print_file_stats(m, task ? task->comm : "<unknown>", stats);

> >  		rcu_read_unlock();

> >  	}

> >

> > @@ -583,6 +605,36 @@ static int i915_gem_pageflip_info(struct seq_file

> *m, void *data)

> >  	return 0;

> >  }

> >

> > +static int i915_gem_batch_pool_info(struct seq_file *m, void *data) {

> > +	struct drm_info_node *node = m->private;

> > +	struct drm_device *dev = node->minor->dev;

> > +	struct drm_i915_private *dev_priv = dev->dev_private;

> > +	struct drm_i915_gem_object *obj;

> > +	int count = 0;

> > +	int ret;

> > +

> > +	ret = mutex_lock_interruptible(&dev->struct_mutex);

> > +	if (ret)

> > +		return ret;

> > +

> > +	seq_puts(m, "cache:\n");

> > +	list_for_each_entry(obj,

> > +			    &dev_priv->mm.batch_pool.cache_list,

> > +			    batch_pool_list) {

> > +		seq_puts(m, "   ");

> > +		describe_obj(m, obj);

> > +		seq_putc(m, '\n');

> > +		count++;

> > +	}

> > +

> > +	seq_printf(m, "total: %d\n", count);

> > +

> > +	mutex_unlock(&dev->struct_mutex);

> > +

> > +	return 0;

> > +}

> > +

> >  static int i915_gem_request_info(struct seq_file *m, void *data)  {

> >  	struct drm_info_node *node = m->private; @@ -4324,6 +4376,7 @@

> > static const struct drm_info_list i915_debugfs_list[] = {

> >  	{"i915_gem_hws_blt", i915_hws_info, 0, (void *)BCS},

> >  	{"i915_gem_hws_bsd", i915_hws_info, 0, (void *)VCS},

> >  	{"i915_gem_hws_vebox", i915_hws_info, 0, (void *)VECS},

> > +	{"i915_gem_batch_pool", i915_gem_batch_pool_info, 0},

> >  	{"i915_frequency_info", i915_frequency_info, 0},

> >  	{"i915_drpc_info", i915_drpc_info, 0},

> >  	{"i915_emon_status", i915_emon_status, 0}, diff --git

> > a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h

> > index 11e85cb..f3e27e9 100644

> > --- a/drivers/gpu/drm/i915/i915_drv.h

> > +++ b/drivers/gpu/drm/i915/i915_drv.h

> > @@ -1129,6 +1129,11 @@ struct intel_l3_parity {

> >  	int which_slice;

> >  };

> >

> > +struct i915_gem_batch_pool {

> > +	struct drm_device *dev;

> > +	struct list_head cache_list;

> > +};

> > +

> >  struct i915_gem_mm {

> >  	/** Memory allocator for GTT stolen memory */

> >  	struct drm_mm stolen;

> > @@ -1142,6 +1147,13 @@ 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) */

> >

> > @@ -1872,6 +1884,8 @@ 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

> > @@ -2876,6 +2890,13 @@ 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 de241eb..2f14ae1 100644

> > --- a/drivers/gpu/drm/i915/i915_gem.c

> > +++ b/drivers/gpu/drm/i915/i915_gem.c

> > @@ -4384,6 +4384,7 @@ 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..e9349e3

> > --- /dev/null

> > +++ b/drivers/gpu/drm/i915/i915_gem_batch_pool.c

> > @@ -0,0 +1,132 @@

> > +/*

> > + * 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->cache_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->cache_list)) {

> > +		struct drm_i915_gem_object *obj =

> > +			list_first_entry(&pool->cache_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);

> > +	}

> > +}

> > +

> > +/**

> > + * 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;

> > +

> > +	WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex));

> > +

> > +	list_for_each_entry_safe(tmp, next,

> > +			&pool->cache_list, batch_pool_list) {

> > +

> > +		if (tmp->active)

> > +			continue;

> > +

> > +		/* While we're looping, do some clean up */

> > +		if (tmp->madv == __I915_MADV_PURGED) {

> > +			list_del(&tmp->batch_pool_list);

> > +			drm_gem_object_unreference(&tmp->base);

> > +			continue;

> > +		}

> > +

> > +		/*

> > +		 * 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 (!obj) {

> > +		obj = i915_gem_alloc_object(pool->dev, size);

> > +		if (!obj)

> > +			return ERR_PTR(-ENOMEM);

> > +

> > +		list_add_tail(&obj->batch_pool_list, &pool->cache_list);

> > +	}

> 

> Shouldn't we have a else list_move_tail here to keep the list in lru order?

> -Daniel

> 

> > +

> > +	return obj;

> > +}

> > --

> > 1.9.1

> >

> > _______________________________________________

> > Intel-gfx mailing list

> > [e-mail]

> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx

> 

> --

> Daniel Vetter

> Software Engineer, Intel Corporation

> [phone] - http://blog.ffwll.ch

> _______________________________________________

> Intel-gfx mailing list

> [e-mail]

> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

Michael H. Nguyen Dec. 10, 2014, 4:33 p.m. UTC | #4

Hi Jon,

On 12/10/2014 03:06 AM, Bloomfield, Jon wrote:
>> -----Original Message-----
>> From: Intel-gfx [mailto:[e-mail]] On Behalf
>> Of Daniel Vetter
>> Sent: Tuesday, December 09, 2014 1:18 PM
>> To: Nguyen, Michael H
>> Cc: Brad Volkin; [e-mail]
>> Subject: Re: [Intel-gfx] [PATCH v6 1/5] drm/i915: Implement a framework for
>> batch buffer pools
>>
>> On Mon, Dec 08, 2014 at 02:33:46PM -0800, [e-mail]
>> wrote:
>>> From: Brad Volkin <[e-mail]>
>>>
>>> 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)
>>>
>>> v7:
>>> - Use single list instead of two. (Chris W)
>>> - s/active_list/cache_list
>>> - Squashed in debug patches (Chris W)
>>>    drm/i915: Add a batch pool debugfs file
>>>
>>>    It provides some useful information about the buffers in
>>>    the global command parser batch pool.
>>>
>>>    v2: rebase on global pool instead of per-ring pools
>>>    v3: rebase
>>>
>>>    drm/i915: Add batch pool details to i915_gem_objects debugfs
>>>
>>>    To better account for the potentially large memory consumption
>>>    of the batch pool.
>>>
>>> Issue: VIZ-4719
>>> Signed-off-by: Brad Volkin <[e-mail]>
>>> ---
>>>   Documentation/DocBook/drm.tmpl             |   5 ++
>>>   drivers/gpu/drm/i915/Makefile              |   1 +
>>>   drivers/gpu/drm/i915/i915_debugfs.c        |  71 ++++++++++++++--
>>>   drivers/gpu/drm/i915/i915_drv.h            |  21 +++++
>>>   drivers/gpu/drm/i915/i915_gem.c            |   1 +
>>>   drivers/gpu/drm/i915/i915_gem_batch_pool.c | 132
>>> +++++++++++++++++++++++++++++
>>>   6 files changed, 222 insertions(+), 9 deletions(-)  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 85287cb..022923a 100644
>>> --- a/Documentation/DocBook/drm.tmpl
>>> +++ b/Documentation/DocBook/drm.tmpl
>>> @@ -4029,6 +4029,11 @@ 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_debugfs.c
>>> b/drivers/gpu/drm/i915/i915_debugfs.c
>>> index d0e445e..3c3bf98 100644
>>> --- a/drivers/gpu/drm/i915/i915_debugfs.c
>>> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
>>> @@ -359,6 +359,33 @@ static int per_file_stats(int id, void *ptr, void
>> *data)
>>>   	return 0;
>>>   }
>>>
>>> +#define print_file_stats(m, name, stats) \
>>> +	seq_printf(m, "%s: %u objects, %zu bytes (%zu active, %zu inactive,
>> %zu global, %zu shared, %zu unbound)\n", \
>>> +		   name, \
>>> +		   stats.count, \
>>> +		   stats.total, \
>>> +		   stats.active, \
>>> +		   stats.inactive, \
>>> +		   stats.global, \
>>> +		   stats.shared, \
>>> +		   stats.unbound)
>
> "print_file_stats" might be better named "print_obj_stats" or similar. As it stands
> there is nothing in its name to suggest its purpose is to describe an object.
I guess the fnc name 'print_file_stats' was chosen b/c it takes a 
'stats' parameter of type 'struct file_stats' and prints the members. 
Seems fair to leave it I think as its generic.
>
>
>>> +
>>> +static void print_batch_pool_stats(struct seq_file *m,
>>> +				   struct drm_i915_private *dev_priv) {
>>> +	struct drm_i915_gem_object *obj;
>>> +	struct file_stats stats;
>>> +
>>> +	memset(&stats, 0, sizeof(stats));
>>> +
>>> +	list_for_each_entry(obj,
>>> +			    &dev_priv->mm.batch_pool.cache_list,
>>> +			    batch_pool_list)
>>> +		per_file_stats(0, obj, &stats);
>
> Shouldn't we be holding the batch_pool lock here ?
Think we're okay here. The callers of print_batch_pool_stats() hold 
dev->struct_mutex.

Thanks,
-Mike
>
>
>>> +
>>> +	print_file_stats(m, "batch pool", stats); }
>>> +
>>>   #define count_vmas(list, member) do { \
>>>   	list_for_each_entry(vma, list, member) { \
>>>   		size += i915_gem_obj_ggtt_size(vma->obj); \ @@ -441,6
>> +468,9 @@
>>> static int i915_gem_object_info(struct seq_file *m, void* data)
>>>   		   dev_priv->gtt.mappable_end - dev_priv->gtt.base.start);
>>>
>>>   	seq_putc(m, '\n');
>>> +	print_batch_pool_stats(m, dev_priv);
>>> +
>>> +	seq_putc(m, '\n');
>>>   	list_for_each_entry_reverse(file, &dev->filelist, lhead) {
>>>   		struct file_stats stats;
>>>   		struct task_struct *task;
>>> @@ -458,15 +488,7 @@ static int i915_gem_object_info(struct seq_file *m,
>> void* data)
>>>   		 */
>>>   		rcu_read_lock();
>>>   		task = pid_task(file->pid, PIDTYPE_PID);
>>> -		seq_printf(m, "%s: %u objects, %zu bytes (%zu active, %zu
>> inactive, %zu global, %zu shared, %zu unbound)\n",
>>> -			   task ? task->comm : "<unknown>",
>>> -			   stats.count,
>>> -			   stats.total,
>>> -			   stats.active,
>>> -			   stats.inactive,
>>> -			   stats.global,
>>> -			   stats.shared,
>>> -			   stats.unbound);
>>> +		print_file_stats(m, task ? task->comm : "<unknown>", stats);
>>>   		rcu_read_unlock();
>>>   	}
>>>
>>> @@ -583,6 +605,36 @@ static int i915_gem_pageflip_info(struct seq_file
>> *m, void *data)
>>>   	return 0;
>>>   }
>>>
>>> +static int i915_gem_batch_pool_info(struct seq_file *m, void *data) {
>>> +	struct drm_info_node *node = m->private;
>>> +	struct drm_device *dev = node->minor->dev;
>>> +	struct drm_i915_private *dev_priv = dev->dev_private;
>>> +	struct drm_i915_gem_object *obj;
>>> +	int count = 0;
>>> +	int ret;
>>> +
>>> +	ret = mutex_lock_interruptible(&dev->struct_mutex);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	seq_puts(m, "cache:\n");
>>> +	list_for_each_entry(obj,
>>> +			    &dev_priv->mm.batch_pool.cache_list,
>>> +			    batch_pool_list) {
>>> +		seq_puts(m, "   ");
>>> +		describe_obj(m, obj);
>>> +		seq_putc(m, '\n');
>>> +		count++;
>>> +	}
>>> +
>>> +	seq_printf(m, "total: %d\n", count);
>>> +
>>> +	mutex_unlock(&dev->struct_mutex);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>>   static int i915_gem_request_info(struct seq_file *m, void *data)  {
>>>   	struct drm_info_node *node = m->private; @@ -4324,6 +4376,7 @@
>>> static const struct drm_info_list i915_debugfs_list[] = {
>>>   	{"i915_gem_hws_blt", i915_hws_info, 0, (void *)BCS},
>>>   	{"i915_gem_hws_bsd", i915_hws_info, 0, (void *)VCS},
>>>   	{"i915_gem_hws_vebox", i915_hws_info, 0, (void *)VECS},
>>> +	{"i915_gem_batch_pool", i915_gem_batch_pool_info, 0},
>>>   	{"i915_frequency_info", i915_frequency_info, 0},
>>>   	{"i915_drpc_info", i915_drpc_info, 0},
>>>   	{"i915_emon_status", i915_emon_status, 0}, diff --git
>>> a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>>> index 11e85cb..f3e27e9 100644
>>> --- a/drivers/gpu/drm/i915/i915_drv.h
>>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>>> @@ -1129,6 +1129,11 @@ struct intel_l3_parity {
>>>   	int which_slice;
>>>   };
>>>
>>> +struct i915_gem_batch_pool {
>>> +	struct drm_device *dev;
>>> +	struct list_head cache_list;
>>> +};
>>> +
>>>   struct i915_gem_mm {
>>>   	/** Memory allocator for GTT stolen memory */
>>>   	struct drm_mm stolen;
>>> @@ -1142,6 +1147,13 @@ 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) */
>>>
>>> @@ -1872,6 +1884,8 @@ 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
>>> @@ -2876,6 +2890,13 @@ 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 de241eb..2f14ae1 100644
>>> --- a/drivers/gpu/drm/i915/i915_gem.c
>>> +++ b/drivers/gpu/drm/i915/i915_gem.c
>>> @@ -4384,6 +4384,7 @@ 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..e9349e3
>>> --- /dev/null
>>> +++ b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
>>> @@ -0,0 +1,132 @@
>>> +/*
>>> + * 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->cache_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->cache_list)) {
>>> +		struct drm_i915_gem_object *obj =
>>> +			list_first_entry(&pool->cache_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);
>>> +	}
>>> +}
>>> +
>>> +/**
>>> + * 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;
>>> +
>>> +	WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex));
>>> +
>>> +	list_for_each_entry_safe(tmp, next,
>>> +			&pool->cache_list, batch_pool_list) {
>>> +
>>> +		if (tmp->active)
>>> +			continue;
>>> +
>>> +		/* While we're looping, do some clean up */
>>> +		if (tmp->madv == __I915_MADV_PURGED) {
>>> +			list_del(&tmp->batch_pool_list);
>>> +			drm_gem_object_unreference(&tmp->base);
>>> +			continue;
>>> +		}
>>> +
>>> +		/*
>>> +		 * 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 (!obj) {
>>> +		obj = i915_gem_alloc_object(pool->dev, size);
>>> +		if (!obj)
>>> +			return ERR_PTR(-ENOMEM);
>>> +
>>> +		list_add_tail(&obj->batch_pool_list, &pool->cache_list);
>>> +	}
>>
>> Shouldn't we have a else list_move_tail here to keep the list in lru order?
>> -Daniel
>>
>>> +
>>> +	return obj;
>>> +}
>>> --
>>> 1.9.1
>>>
>>> _______________________________________________
>>> Intel-gfx mailing list
>>> [e-mail]
>>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>>
>> --
>> Daniel Vetter
>> Software Engineer, Intel Corporation
>> [phone] - http://blog.ffwll.ch
>> _______________________________________________
>> Intel-gfx mailing list
>> [e-mail]
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

Bloomfield, Jon Dec. 10, 2014, 4:41 p.m. UTC | #5

> -----Original Message-----

> From: Nguyen, Michael H

> Sent: Wednesday, December 10, 2014 4:34 PM

> To: Bloomfield, Jon

> Cc: Daniel Vetter; [e-mail]

> Subject: Re: [Intel-gfx] [PATCH v6 1/5] drm/i915: Implement a framework for

> batch buffer pools

> 

> Hi Jon,

> 

> On 12/10/2014 03:06 AM, Bloomfield, Jon wrote:

> >> -----Original Message-----

> >> From: Intel-gfx [mailto:[e-mail]] On

> >> Behalf Of Daniel Vetter

> >> Sent: Tuesday, December 09, 2014 1:18 PM

> >> To: Nguyen, Michael H

> >> Cc: Brad Volkin; [e-mail]

> >> Subject: Re: [Intel-gfx] [PATCH v6 1/5] drm/i915: Implement a

> >> framework for batch buffer pools

> >>

> >> On Mon, Dec 08, 2014 at 02:33:46PM -0800, [e-mail]

> >> wrote:

> >>> From: Brad Volkin <[e-mail]>

> >>>

> >>> 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)

> >>>

> >>> v7:

> >>> - Use single list instead of two. (Chris W)

> >>> - s/active_list/cache_list

> >>> - Squashed in debug patches (Chris W)

> >>>    drm/i915: Add a batch pool debugfs file

> >>>

> >>>    It provides some useful information about the buffers in

> >>>    the global command parser batch pool.

> >>>

> >>>    v2: rebase on global pool instead of per-ring pools

> >>>    v3: rebase

> >>>

> >>>    drm/i915: Add batch pool details to i915_gem_objects debugfs

> >>>

> >>>    To better account for the potentially large memory consumption

> >>>    of the batch pool.

> >>>

> >>> Issue: VIZ-4719

> >>> Signed-off-by: Brad Volkin <[e-mail]>

> >>> ---

> >>>   Documentation/DocBook/drm.tmpl             |   5 ++

> >>>   drivers/gpu/drm/i915/Makefile              |   1 +

> >>>   drivers/gpu/drm/i915/i915_debugfs.c        |  71 ++++++++++++++--

> >>>   drivers/gpu/drm/i915/i915_drv.h            |  21 +++++

> >>>   drivers/gpu/drm/i915/i915_gem.c            |   1 +

> >>>   drivers/gpu/drm/i915/i915_gem_batch_pool.c | 132

> >>> +++++++++++++++++++++++++++++

> >>>   6 files changed, 222 insertions(+), 9 deletions(-)  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 85287cb..022923a 100644

> >>> --- a/Documentation/DocBook/drm.tmpl

> >>> +++ b/Documentation/DocBook/drm.tmpl

> >>> @@ -4029,6 +4029,11 @@ 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_debugfs.c

> >>> b/drivers/gpu/drm/i915/i915_debugfs.c

> >>> index d0e445e..3c3bf98 100644

> >>> --- a/drivers/gpu/drm/i915/i915_debugfs.c

> >>> +++ b/drivers/gpu/drm/i915/i915_debugfs.c

> >>> @@ -359,6 +359,33 @@ static int per_file_stats(int id, void *ptr,

> >>> void

> >> *data)

> >>>   	return 0;

> >>>   }

> >>>

> >>> +#define print_file_stats(m, name, stats) \

> >>> +	seq_printf(m, "%s: %u objects, %zu bytes (%zu active, %zu

> >>> +inactive,

> >> %zu global, %zu shared, %zu unbound)\n", \

> >>> +		   name, \

> >>> +		   stats.count, \

> >>> +		   stats.total, \

> >>> +		   stats.active, \

> >>> +		   stats.inactive, \

> >>> +		   stats.global, \

> >>> +		   stats.shared, \

> >>> +		   stats.unbound)

> >

> > "print_file_stats" might be better named "print_obj_stats" or similar.

> > As it stands there is nothing in its name to suggest its purpose is to describe

> an object.

> I guess the fnc name 'print_file_stats' was chosen b/c it takes a 'stats'

> parameter of type 'struct file_stats' and prints the members.

> Seems fair to leave it I think as its generic.


Ok, agreed.

> >

> >

> >>> +

> >>> +static void print_batch_pool_stats(struct seq_file *m,

> >>> +				   struct drm_i915_private *dev_priv) {

> >>> +	struct drm_i915_gem_object *obj;

> >>> +	struct file_stats stats;

> >>> +

> >>> +	memset(&stats, 0, sizeof(stats));

> >>> +

> >>> +	list_for_each_entry(obj,

> >>> +			    &dev_priv->mm.batch_pool.cache_list,

> >>> +			    batch_pool_list)

> >>> +		per_file_stats(0, obj, &stats);

> >

> > Shouldn't we be holding the batch_pool lock here ?

> Think we're okay here. The callers of print_batch_pool_stats() hold

> dev->struct_mutex.

> 

> Thanks,

> -Mike


But then, why do we take the batch_pool lock in i915_gem_batch_pool_info() ?

> >

> >

> >>> +

> >>> +	print_file_stats(m, "batch pool", stats); }

> >>> +

> >>>   #define count_vmas(list, member) do { \

> >>>   	list_for_each_entry(vma, list, member) { \

> >>>   		size += i915_gem_obj_ggtt_size(vma->obj); \ @@ -441,6

> >> +468,9 @@

> >>> static int i915_gem_object_info(struct seq_file *m, void* data)

> >>>   		   dev_priv->gtt.mappable_end - dev_priv->gtt.base.start);

> >>>

> >>>   	seq_putc(m, '\n');

> >>> +	print_batch_pool_stats(m, dev_priv);

> >>> +

> >>> +	seq_putc(m, '\n');

> >>>   	list_for_each_entry_reverse(file, &dev->filelist, lhead) {

> >>>   		struct file_stats stats;

> >>>   		struct task_struct *task;

> >>> @@ -458,15 +488,7 @@ static int i915_gem_object_info(struct seq_file

> >>> *m,

> >> void* data)

> >>>   		 */

> >>>   		rcu_read_lock();

> >>>   		task = pid_task(file->pid, PIDTYPE_PID);

> >>> -		seq_printf(m, "%s: %u objects, %zu bytes (%zu active, %zu

> >> inactive, %zu global, %zu shared, %zu unbound)\n",

> >>> -			   task ? task->comm : "<unknown>",

> >>> -			   stats.count,

> >>> -			   stats.total,

> >>> -			   stats.active,

> >>> -			   stats.inactive,

> >>> -			   stats.global,

> >>> -			   stats.shared,

> >>> -			   stats.unbound);

> >>> +		print_file_stats(m, task ? task->comm : "<unknown>", stats);

> >>>   		rcu_read_unlock();

> >>>   	}

> >>>

> >>> @@ -583,6 +605,36 @@ static int i915_gem_pageflip_info(struct

> >>> seq_file

> >> *m, void *data)

> >>>   	return 0;

> >>>   }

> >>>

> >>> +static int i915_gem_batch_pool_info(struct seq_file *m, void *data) {

> >>> +	struct drm_info_node *node = m->private;

> >>> +	struct drm_device *dev = node->minor->dev;

> >>> +	struct drm_i915_private *dev_priv = dev->dev_private;

> >>> +	struct drm_i915_gem_object *obj;

> >>> +	int count = 0;

> >>> +	int ret;

> >>> +

> >>> +	ret = mutex_lock_interruptible(&dev->struct_mutex);

> >>> +	if (ret)

> >>> +		return ret;

> >>> +

> >>> +	seq_puts(m, "cache:\n");

> >>> +	list_for_each_entry(obj,

> >>> +			    &dev_priv->mm.batch_pool.cache_list,

> >>> +			    batch_pool_list) {

> >>> +		seq_puts(m, "   ");

> >>> +		describe_obj(m, obj);

> >>> +		seq_putc(m, '\n');

> >>> +		count++;

> >>> +	}

> >>> +

> >>> +	seq_printf(m, "total: %d\n", count);

> >>> +

> >>> +	mutex_unlock(&dev->struct_mutex);

> >>> +

> >>> +	return 0;

> >>> +}

> >>> +

> >>>   static int i915_gem_request_info(struct seq_file *m, void *data)  {

> >>>   	struct drm_info_node *node = m->private; @@ -4324,6 +4376,7 @@

> >>> static const struct drm_info_list i915_debugfs_list[] = {

> >>>   	{"i915_gem_hws_blt", i915_hws_info, 0, (void *)BCS},

> >>>   	{"i915_gem_hws_bsd", i915_hws_info, 0, (void *)VCS},

> >>>   	{"i915_gem_hws_vebox", i915_hws_info, 0, (void *)VECS},

> >>> +	{"i915_gem_batch_pool", i915_gem_batch_pool_info, 0},

> >>>   	{"i915_frequency_info", i915_frequency_info, 0},

> >>>   	{"i915_drpc_info", i915_drpc_info, 0},

> >>>   	{"i915_emon_status", i915_emon_status, 0}, diff --git

> >>> a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h

> >>> index 11e85cb..f3e27e9 100644

> >>> --- a/drivers/gpu/drm/i915/i915_drv.h

> >>> +++ b/drivers/gpu/drm/i915/i915_drv.h

> >>> @@ -1129,6 +1129,11 @@ struct intel_l3_parity {

> >>>   	int which_slice;

> >>>   };

> >>>

> >>> +struct i915_gem_batch_pool {

> >>> +	struct drm_device *dev;

> >>> +	struct list_head cache_list;

> >>> +};

> >>> +

> >>>   struct i915_gem_mm {

> >>>   	/** Memory allocator for GTT stolen memory */

> >>>   	struct drm_mm stolen;

> >>> @@ -1142,6 +1147,13 @@ 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) */

> >>>

> >>> @@ -1872,6 +1884,8 @@ 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 @@ -2876,6 +2890,13 @@ 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 de241eb..2f14ae1 100644

> >>> --- a/drivers/gpu/drm/i915/i915_gem.c

> >>> +++ b/drivers/gpu/drm/i915/i915_gem.c

> >>> @@ -4384,6 +4384,7 @@ 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..e9349e3

> >>> --- /dev/null

> >>> +++ b/drivers/gpu/drm/i915/i915_gem_batch_pool.c

> >>> @@ -0,0 +1,132 @@

> >>> +/*

> >>> + * 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->cache_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->cache_list)) {

> >>> +		struct drm_i915_gem_object *obj =

> >>> +			list_first_entry(&pool->cache_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);

> >>> +	}

> >>> +}

> >>> +

> >>> +/**

> >>> + * 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;

> >>> +

> >>> +	WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex));

> >>> +

> >>> +	list_for_each_entry_safe(tmp, next,

> >>> +			&pool->cache_list, batch_pool_list) {

> >>> +

> >>> +		if (tmp->active)

> >>> +			continue;

> >>> +

> >>> +		/* While we're looping, do some clean up */

> >>> +		if (tmp->madv == __I915_MADV_PURGED) {

> >>> +			list_del(&tmp->batch_pool_list);

> >>> +			drm_gem_object_unreference(&tmp->base);

> >>> +			continue;

> >>> +		}

> >>> +

> >>> +		/*

> >>> +		 * 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 (!obj) {

> >>> +		obj = i915_gem_alloc_object(pool->dev, size);

> >>> +		if (!obj)

> >>> +			return ERR_PTR(-ENOMEM);

> >>> +

> >>> +		list_add_tail(&obj->batch_pool_list, &pool->cache_list);

> >>> +	}

> >>

> >> Shouldn't we have a else list_move_tail here to keep the list in lru order?

> >> -Daniel

> >>

> >>> +

> >>> +	return obj;

> >>> +}

> >>> --

> >>> 1.9.1

> >>>

> >>> _______________________________________________

> >>> Intel-gfx mailing list

> >>> [e-mail]

> >>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

> >>

> >> --

> >> Daniel Vetter

> >> Software Engineer, Intel Corporation

> >> [phone] - http://blog.ffwll.ch

> >> _______________________________________________

> >> Intel-gfx mailing list

> >> [e-mail]

> >> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

Michael H. Nguyen Dec. 10, 2014, 5:05 p.m. UTC | #6

On 12/10/2014 08:41 AM, Bloomfield, Jon wrote:
> why do we take the batch_pool lock in i915_gem_batch_pool_info() ?
i915_gem_batch_pool_info() is a new debugfs entry while 
print_batch_pool_stats() is just an internal fnc, called from the 
debugfs entry i915_gem_object_info(). i915_gem_object_info() handles the 
locks.

Patch

diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
index 85287cb..022923a 100644
--- a/Documentation/DocBook/drm.tmpl
+++ b/Documentation/DocBook/drm.tmpl
@@ -4029,6 +4029,11 @@  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_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index d0e445e..3c3bf98 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -359,6 +359,33 @@  static int per_file_stats(int id, void *ptr, void *data)
 	return 0;
 }
 
+#define print_file_stats(m, name, stats) \
+	seq_printf(m, "%s: %u objects, %zu bytes (%zu active, %zu inactive, %zu global, %zu shared, %zu unbound)\n", \
+		   name, \
+		   stats.count, \
+		   stats.total, \
+		   stats.active, \
+		   stats.inactive, \
+		   stats.global, \
+		   stats.shared, \
+		   stats.unbound)
+
+static void print_batch_pool_stats(struct seq_file *m,
+				   struct drm_i915_private *dev_priv)
+{
+	struct drm_i915_gem_object *obj;
+	struct file_stats stats;
+
+	memset(&stats, 0, sizeof(stats));
+
+	list_for_each_entry(obj,
+			    &dev_priv->mm.batch_pool.cache_list,
+			    batch_pool_list)
+		per_file_stats(0, obj, &stats);
+
+	print_file_stats(m, "batch pool", stats);
+}
+
 #define count_vmas(list, member) do { \
 	list_for_each_entry(vma, list, member) { \
 		size += i915_gem_obj_ggtt_size(vma->obj); \
@@ -441,6 +468,9 @@  static int i915_gem_object_info(struct seq_file *m, void* data)
 		   dev_priv->gtt.mappable_end - dev_priv->gtt.base.start);
 
 	seq_putc(m, '\n');
+	print_batch_pool_stats(m, dev_priv);
+
+	seq_putc(m, '\n');
 	list_for_each_entry_reverse(file, &dev->filelist, lhead) {
 		struct file_stats stats;
 		struct task_struct *task;
@@ -458,15 +488,7 @@  static int i915_gem_object_info(struct seq_file *m, void* data)
 		 */
 		rcu_read_lock();
 		task = pid_task(file->pid, PIDTYPE_PID);
-		seq_printf(m, "%s: %u objects, %zu bytes (%zu active, %zu inactive, %zu global, %zu shared, %zu unbound)\n",
-			   task ? task->comm : "<unknown>",
-			   stats.count,
-			   stats.total,
-			   stats.active,
-			   stats.inactive,
-			   stats.global,
-			   stats.shared,
-			   stats.unbound);
+		print_file_stats(m, task ? task->comm : "<unknown>", stats);
 		rcu_read_unlock();
 	}
 
@@ -583,6 +605,36 @@  static int i915_gem_pageflip_info(struct seq_file *m, void *data)
 	return 0;
 }
 
+static int i915_gem_batch_pool_info(struct seq_file *m, void *data)
+{
+	struct drm_info_node *node = m->private;
+	struct drm_device *dev = node->minor->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_i915_gem_object *obj;
+	int count = 0;
+	int ret;
+
+	ret = mutex_lock_interruptible(&dev->struct_mutex);
+	if (ret)
+		return ret;
+
+	seq_puts(m, "cache:\n");
+	list_for_each_entry(obj,
+			    &dev_priv->mm.batch_pool.cache_list,
+			    batch_pool_list) {
+		seq_puts(m, "   ");
+		describe_obj(m, obj);
+		seq_putc(m, '\n');
+		count++;
+	}
+
+	seq_printf(m, "total: %d\n", count);
+
+	mutex_unlock(&dev->struct_mutex);
+
+	return 0;
+}
+
 static int i915_gem_request_info(struct seq_file *m, void *data)
 {
 	struct drm_info_node *node = m->private;
@@ -4324,6 +4376,7 @@  static const struct drm_info_list i915_debugfs_list[] = {
 	{"i915_gem_hws_blt", i915_hws_info, 0, (void *)BCS},
 	{"i915_gem_hws_bsd", i915_hws_info, 0, (void *)VCS},
 	{"i915_gem_hws_vebox", i915_hws_info, 0, (void *)VECS},
+	{"i915_gem_batch_pool", i915_gem_batch_pool_info, 0},
 	{"i915_frequency_info", i915_frequency_info, 0},
 	{"i915_drpc_info", i915_drpc_info, 0},
 	{"i915_emon_status", i915_emon_status, 0},
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 11e85cb..f3e27e9 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1129,6 +1129,11 @@  struct intel_l3_parity {
 	int which_slice;
 };
 
+struct i915_gem_batch_pool {
+	struct drm_device *dev;
+	struct list_head cache_list;
+};
+
 struct i915_gem_mm {
 	/** Memory allocator for GTT stolen memory */
 	struct drm_mm stolen;
@@ -1142,6 +1147,13 @@  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) */
 
@@ -1872,6 +1884,8 @@  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
@@ -2876,6 +2890,13 @@  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 de241eb..2f14ae1 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4384,6 +4384,7 @@  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..e9349e3
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
@@ -0,0 +1,132 @@ 
+/*
+ * 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->cache_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->cache_list)) {
+		struct drm_i915_gem_object *obj =
+			list_first_entry(&pool->cache_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);
+	}
+}
+
+/**
+ * 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;
+
+	WARN_ON(!mutex_is_locked(&pool->dev->struct_mutex));
+
+	list_for_each_entry_safe(tmp, next,
+			&pool->cache_list, batch_pool_list) {
+
+		if (tmp->active)
+			continue;
+
+		/* While we're looping, do some clean up */
+		if (tmp->madv == __I915_MADV_PURGED) {
+			list_del(&tmp->batch_pool_list);
+			drm_gem_object_unreference(&tmp->base);
+			continue;
+		}
+
+		/*
+		 * 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 (!obj) {
+		obj = i915_gem_alloc_object(pool->dev, size);
+		if (!obj)
+			return ERR_PTR(-ENOMEM);
+
+		list_add_tail(&obj->batch_pool_list, &pool->cache_list);
+	}
+
+	return obj;
+}