[RFC,2/8] drm/i915: Reference count struct drm_i915_file_private
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Message ID 20191219180019.25562-3-tvrtko.ursulin@linux.intel.com
State New
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Series
  • Per client engine busyness
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Commit Message

Tvrtko Ursulin Dec. 19, 2019, 6 p.m. UTC
From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

In the following patches we will develope a need to peek into the client
owned data from any potential leftover contexts.

To facilitate this add reference counting to file_priv.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c |  2 +-
 drivers/gpu/drm/i915/i915_drv.c             |  4 ----
 drivers/gpu/drm/i915/i915_drv.h             |  4 +++-
 drivers/gpu/drm/i915/i915_gem.c             | 14 +++++++++++++-
 4 files changed, 17 insertions(+), 7 deletions(-)

Comments

Chris Wilson Dec. 19, 2019, 8:43 p.m. UTC | #1
Quoting Tvrtko Ursulin (2019-12-19 18:00:13)
> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> 
> In the following patches we will develope a need to peek into the client
> owned data from any potential leftover contexts.
> 
> To facilitate this add reference counting to file_priv.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> ---
>  drivers/gpu/drm/i915/gem/i915_gem_context.c |  2 +-
>  drivers/gpu/drm/i915/i915_drv.c             |  4 ----
>  drivers/gpu/drm/i915/i915_drv.h             |  4 +++-
>  drivers/gpu/drm/i915/i915_gem.c             | 14 +++++++++++++-
>  4 files changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> index e5a7c6f02a47..b482b2e5f31f 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> @@ -853,7 +853,7 @@ int i915_gem_context_open(struct drm_i915_private *i915,
>  void i915_gem_context_close(struct drm_file *file)
>  {
>         struct drm_i915_file_private *file_priv = file->driver_priv;
> -       struct drm_i915_private *i915 = file_priv->dev_priv;
> +       struct drm_i915_private *i915 = file_priv->i915;
>         struct i915_gem_context *ctx;
>         unsigned long idx;
>  
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 8b08cfe30151..0c9c93418068 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1633,13 +1633,9 @@ static void i915_driver_lastclose(struct drm_device *dev)
>  
>  static void i915_driver_postclose(struct drm_device *dev, struct drm_file *file)
>  {
> -       struct drm_i915_file_private *file_priv = file->driver_priv;
> -
>         i915_gem_context_close(file);
>         i915_gem_release(dev, file);
>  
> -       kfree_rcu(file_priv, rcu);

As you are moving the kfree_rcu() into the i915_gem_release (via a put),
I think it also makes sense to move the call for i915_gem_context_close
on this file. Possibly renaming it to i915_gem_file_close() and
s/drm_i915_file_private/i915_gem_file/ or i915_gem_client (with
corresponding name changes) in the process.

For the basic mechanics of this patch though,
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

(Though I still suggest a bit of playing with i915_gem_context_close,
i915_gem_release to tie them together to the notion of the file better.)
-Chris
Tvrtko Ursulin Dec. 20, 2019, 7:55 a.m. UTC | #2
On 19/12/2019 20:43, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2019-12-19 18:00:13)
>> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>>
>> In the following patches we will develope a need to peek into the client
>> owned data from any potential leftover contexts.
>>
>> To facilitate this add reference counting to file_priv.
>>
>> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>> ---
>>   drivers/gpu/drm/i915/gem/i915_gem_context.c |  2 +-
>>   drivers/gpu/drm/i915/i915_drv.c             |  4 ----
>>   drivers/gpu/drm/i915/i915_drv.h             |  4 +++-
>>   drivers/gpu/drm/i915/i915_gem.c             | 14 +++++++++++++-
>>   4 files changed, 17 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
>> index e5a7c6f02a47..b482b2e5f31f 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
>> @@ -853,7 +853,7 @@ int i915_gem_context_open(struct drm_i915_private *i915,
>>   void i915_gem_context_close(struct drm_file *file)
>>   {
>>          struct drm_i915_file_private *file_priv = file->driver_priv;
>> -       struct drm_i915_private *i915 = file_priv->dev_priv;
>> +       struct drm_i915_private *i915 = file_priv->i915;
>>          struct i915_gem_context *ctx;
>>          unsigned long idx;
>>   
>> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
>> index 8b08cfe30151..0c9c93418068 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.c
>> +++ b/drivers/gpu/drm/i915/i915_drv.c
>> @@ -1633,13 +1633,9 @@ static void i915_driver_lastclose(struct drm_device *dev)
>>   
>>   static void i915_driver_postclose(struct drm_device *dev, struct drm_file *file)
>>   {
>> -       struct drm_i915_file_private *file_priv = file->driver_priv;
>> -
>>          i915_gem_context_close(file);
>>          i915_gem_release(dev, file);
>>   
>> -       kfree_rcu(file_priv, rcu);
> 
> As you are moving the kfree_rcu() into the i915_gem_release (via a put),
> I think it also makes sense to move the call for i915_gem_context_close
> on this file. Possibly renaming it to i915_gem_file_close() and
> s/drm_i915_file_private/i915_gem_file/ or i915_gem_client (with
> corresponding name changes) in the process.
> 
> For the basic mechanics of this patch though,
> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
> 
> (Though I still suggest a bit of playing with i915_gem_context_close,
> i915_gem_release to tie them together to the notion of the file better.)

Yes, agreed in principle.

But a) I prefer the release name to match with the fops mindset and b) I 
prefer to leave drm_i915_file_private alone as the top level driver 
private container.

What I am not completely happy with, or say undecided, is whether to 
move the kref into i915_drm_client. I had it like that at one point, 
thinking to only have a smallest needed structure pinned in memory, but 
then I simplified in favour of fewer allocations. Now I think I'd like 
to move the kref into i915_drm_client again. Any opinion here?

In a later patch, when I add the i915_gem_client_get/put helpers they 
are already named like that. Hm okay, I also have a naming confusion 
between struct i915_drm_client and i915_gem_client_get/put(). :)

Regards,

Tvrtko

Patch
diff mbox series

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index e5a7c6f02a47..b482b2e5f31f 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -853,7 +853,7 @@  int i915_gem_context_open(struct drm_i915_private *i915,
 void i915_gem_context_close(struct drm_file *file)
 {
 	struct drm_i915_file_private *file_priv = file->driver_priv;
-	struct drm_i915_private *i915 = file_priv->dev_priv;
+	struct drm_i915_private *i915 = file_priv->i915;
 	struct i915_gem_context *ctx;
 	unsigned long idx;
 
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 8b08cfe30151..0c9c93418068 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1633,13 +1633,9 @@  static void i915_driver_lastclose(struct drm_device *dev)
 
 static void i915_driver_postclose(struct drm_device *dev, struct drm_file *file)
 {
-	struct drm_i915_file_private *file_priv = file->driver_priv;
-
 	i915_gem_context_close(file);
 	i915_gem_release(dev, file);
 
-	kfree_rcu(file_priv, rcu);
-
 	/* Catch up with all the deferred frees from "this" client */
 	i915_gem_flush_free_objects(to_i915(dev));
 }
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 9226c0515506..6f13f0c619e9 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -190,13 +190,15 @@  struct i915_mm_struct;
 struct i915_mmu_object;
 
 struct drm_i915_file_private {
-	struct drm_i915_private *dev_priv;
+	struct kref kref;
 
 	union {
 		struct drm_file *file;
 		struct rcu_head rcu;
 	};
 
+	struct drm_i915_private *i915;
+
 	struct {
 		spinlock_t lock;
 		struct list_head request_list;
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index f19c678ebefc..a52fdae95f58 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1518,6 +1518,14 @@  int i915_gem_freeze_late(struct drm_i915_private *i915)
 	return 0;
 }
 
+static void gem_release(struct kref *kref)
+{
+	struct drm_i915_file_private *fpriv =
+		container_of(kref, typeof(*fpriv), kref);
+
+	kfree_rcu(fpriv, rcu);
+}
+
 void i915_gem_release(struct drm_device *dev, struct drm_file *file)
 {
 	struct drm_i915_file_private *file_priv = file->driver_priv;
@@ -1531,6 +1539,8 @@  void i915_gem_release(struct drm_device *dev, struct drm_file *file)
 	list_for_each_entry(request, &file_priv->mm.request_list, client_link)
 		request->file_priv = NULL;
 	spin_unlock(&file_priv->mm.lock);
+
+	kref_put(&file_priv->kref, gem_release);
 }
 
 int i915_gem_open(struct drm_i915_private *i915, struct drm_file *file)
@@ -1544,8 +1554,10 @@  int i915_gem_open(struct drm_i915_private *i915, struct drm_file *file)
 	if (!file_priv)
 		return -ENOMEM;
 
+	kref_init(&file_priv->kref);
+
 	file->driver_priv = file_priv;
-	file_priv->dev_priv = i915;
+	file_priv->i915 = i915;
 	file_priv->file = file;
 
 	spin_lock_init(&file_priv->mm.lock);