[1/5] drm/ttm: Add common debugfs code for resource managers

Commit Message

Zack Rusin April 7, 2022, 2:56 a.m. UTC

From: Zack Rusin <[e-mail]>

Drivers duplicate the code required to add debugfs entries for various
ttm resource managers. To fix it add common TTM resource manager
code that each driver can reuse.

Because TTM resource managers can be initialized and set a lot later
than TTM device initialization a seperate init function is required.
Specific resource managers can overwrite
ttm_resource_manager_func::debug to get more information from those
debugfs entries.

Signed-off-by: Zack Rusin <[e-mail]>
Cc: Christian Koenig <[e-mail]>
Cc: Huang Rui <[e-mail]>
Cc: David Airlie <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
---
 drivers/gpu/drm/ttm/ttm_resource.c | 65 ++++++++++++++++++++++++++++++
 include/drm/ttm/ttm_resource.h     |  4 ++
 2 files changed, 69 insertions(+)

Comments

Christian König April 7, 2022, 6:01 a.m. UTC | #1

Am 07.04.22 um 04:56 schrieb Zack Rusin:
> From: Zack Rusin <[e-mail]>
>
> Drivers duplicate the code required to add debugfs entries for various
> ttm resource managers. To fix it add common TTM resource manager
> code that each driver can reuse.
>
> Because TTM resource managers can be initialized and set a lot later
> than TTM device initialization a seperate init function is required.
> Specific resource managers can overwrite
> ttm_resource_manager_func::debug to get more information from those
> debugfs entries.
>
> Signed-off-by: Zack Rusin <[e-mail]>
> Cc: Christian Koenig <[e-mail]>
> Cc: Huang Rui <[e-mail]>
> Cc: David Airlie <[e-mail]>
> Cc: Daniel Vetter <[e-mail]>

Ah, yes that was on my TODO list for quite a while as well.

> ---
>   drivers/gpu/drm/ttm/ttm_resource.c | 65 ++++++++++++++++++++++++++++++
>   include/drm/ttm/ttm_resource.h     |  4 ++
>   2 files changed, 69 insertions(+)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_resource.c b/drivers/gpu/drm/ttm/ttm_resource.c
> index 492ba3157e75..6392ad3e9a88 100644
> --- a/drivers/gpu/drm/ttm/ttm_resource.c
> +++ b/drivers/gpu/drm/ttm/ttm_resource.c
> @@ -29,6 +29,8 @@
>   #include <drm/ttm/ttm_resource.h>
>   #include <drm/ttm/ttm_bo_driver.h>
>   
> +#include "ttm_module.h"
> +
>   /**
>    * ttm_lru_bulk_move_init - initialize a bulk move structure
>    * @bulk: the structure to init
> @@ -644,3 +646,66 @@ ttm_kmap_iter_linear_io_fini(struct ttm_kmap_iter_linear_io *iter_io,
>   
>   	ttm_mem_io_free(bdev, mem);
>   }
> +
> +#if defined(CONFIG_DEBUG_FS)
> +
> +#define TTM_RES_MAN_SHOW(i) \
> +	static int ttm_resource_manager##i##_show(struct seq_file *m, void *unused) \
> +	{ \
> +		struct ttm_device *bdev = (struct ttm_device *)m->private; \
> +		struct ttm_resource_manager *man = ttm_manager_type(bdev, i); \
> +		struct drm_printer p = drm_seq_file_printer(m); \
> +		ttm_resource_manager_debug(man, &p); \
> +		return 0; \
> +	}\
> +	DEFINE_SHOW_ATTRIBUTE(ttm_resource_manager##i)
> +
> +TTM_RES_MAN_SHOW(0);
> +TTM_RES_MAN_SHOW(1);
> +TTM_RES_MAN_SHOW(2);
> +TTM_RES_MAN_SHOW(3);
> +TTM_RES_MAN_SHOW(4);
> +TTM_RES_MAN_SHOW(5);
> +TTM_RES_MAN_SHOW(6);

Uff, please not a static array.

> +
> +#endif
> +
> +/**
> + * ttm_resource_manager_debugfs_init - Setup debugfs entries for specified
> + * resource managers.
> + * @bdev: The TTM device
> + * @file_names: A mapping between TTM_TT placements and the debugfs file
> + * names
> + * @num_file_names: The array size of @file_names.
> + *
> + * This function setups up debugfs files that can be used to look
> + * at debug statistics of the specified ttm_resource_managers.
> + * @file_names array is used to figure out which ttm placements
> + * will get debugfs files created for them.
> + */
> +void
> +ttm_resource_manager_debugfs_init(struct ttm_device *bdev,
> +				  const char * const file_names[],
> +				  uint32_t num_file_names)
> +{
> +#if defined(CONFIG_DEBUG_FS)
> +	uint32_t i;
> +	const struct file_operations *fops[] = {
> +		&ttm_resource_manager0_fops,
> +		&ttm_resource_manager1_fops,
> +		&ttm_resource_manager2_fops,
> +		&ttm_resource_manager3_fops,
> +		&ttm_resource_manager4_fops,
> +		&ttm_resource_manager5_fops,
> +		&ttm_resource_manager6_fops,
> +	};
> +
> +	WARN_ON(num_file_names > ARRAY_SIZE(fops));
> +
> +	for (i = 0; i < num_file_names; ++i)
> +		if (file_names[i] && fops[i])
> +			debugfs_create_file(file_names[i], 0444,
> +					    ttm_debugfs_root, bdev, fops[i]);

You can give the ttm_resource_manager directly as parameter here instead 
of the bdev and avoid the whole handling with the macro and global arrays.

Then ttm_debugfs_root is the global directory for TTM and not meant to 
be used for driver specific data.

Rather do it like this: void ttm_resource_manager_create_debugfs(struct 
ttm_resource_manager *man, struct dentry * parent, const char *name);

Calling that for each file the driver wants to create should be trivial.

Thanks,
Christian.

> +#endif
> +}
> +EXPORT_SYMBOL(ttm_resource_manager_debugfs_init);
> diff --git a/include/drm/ttm/ttm_resource.h b/include/drm/ttm/ttm_resource.h
> index 4428a62e5f0e..3c85cdd21ca5 100644
> --- a/include/drm/ttm/ttm_resource.h
> +++ b/include/drm/ttm/ttm_resource.h
> @@ -383,4 +383,8 @@ ttm_kmap_iter_linear_io_init(struct ttm_kmap_iter_linear_io *iter_io,
>   void ttm_kmap_iter_linear_io_fini(struct ttm_kmap_iter_linear_io *iter_io,
>   				  struct ttm_device *bdev,
>   				  struct ttm_resource *mem);
> +
> +void ttm_resource_manager_debugfs_init(struct ttm_device *bdev,
> +				       const char * const file_name[],
> +				       uint32_t num_file_names);
>   #endif

Zack Rusin April 7, 2022, 2:15 p.m. UTC | #2

On Thu, 2022-04-07 at 08:01 +0200, Christian König wrote:
> Am 07.04.22 um 04:56 schrieb Zack Rusin:
> > From: Zack Rusin <[e-mail]>
> > 
> > Drivers duplicate the code required to add debugfs entries for
> > various
> > ttm resource managers. To fix it add common TTM resource manager
> > code that each driver can reuse.
> > 
> > Because TTM resource managers can be initialized and set a lot
> > later
> > than TTM device initialization a seperate init function is
> > required.
> > Specific resource managers can overwrite
> > ttm_resource_manager_func::debug to get more information from those
> > debugfs entries.
> > 
> > Signed-off-by: Zack Rusin <[e-mail]>
> > Cc: Christian Koenig <[e-mail]>
> > Cc: Huang Rui <[e-mail]>
> > Cc: David Airlie <[e-mail]>
> > Cc: Daniel Vetter <[e-mail]>
> 
> Ah, yes that was on my TODO list for quite a while as well.
> 
> > ---
> >   drivers/gpu/drm/ttm/ttm_resource.c | 65
> > ++++++++++++++++++++++++++++++
> >   include/drm/ttm/ttm_resource.h     |  4 ++
> >   2 files changed, 69 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/ttm/ttm_resource.c
> > b/drivers/gpu/drm/ttm/ttm_resource.c
> > index 492ba3157e75..6392ad3e9a88 100644
> > --- a/drivers/gpu/drm/ttm/ttm_resource.c
> > +++ b/drivers/gpu/drm/ttm/ttm_resource.c
> > @@ -29,6 +29,8 @@
> >   #include <drm/ttm/ttm_resource.h>
> >   #include <drm/ttm/ttm_bo_driver.h>
> > 
> > +#include "ttm_module.h"
> > +
> >   /**
> >    * ttm_lru_bulk_move_init - initialize a bulk move structure
> >    * @bulk: the structure to init
> > @@ -644,3 +646,66 @@ ttm_kmap_iter_linear_io_fini(struct
> > ttm_kmap_iter_linear_io *iter_io,
> > 
> >       ttm_mem_io_free(bdev, mem);
> >   }
> > +
> > +#if defined(CONFIG_DEBUG_FS)
> > +
> > +#define TTM_RES_MAN_SHOW(i) \
> > +     static int ttm_resource_manager##i##_show(struct seq_file *m,
> > void *unused) \
> > +     { \
> > +             struct ttm_device *bdev = (struct ttm_device *)m-
> > >private; \
> > +             struct ttm_resource_manager *man =
> > ttm_manager_type(bdev, i); \
> > +             struct drm_printer p = drm_seq_file_printer(m); \
> > +             ttm_resource_manager_debug(man, &p); \
> > +             return 0; \
> > +     }\
> > +     DEFINE_SHOW_ATTRIBUTE(ttm_resource_manager##i)
> > +
> > +TTM_RES_MAN_SHOW(0);
> > +TTM_RES_MAN_SHOW(1);
> > +TTM_RES_MAN_SHOW(2);
> > +TTM_RES_MAN_SHOW(3);
> > +TTM_RES_MAN_SHOW(4);
> > +TTM_RES_MAN_SHOW(5);
> > +TTM_RES_MAN_SHOW(6);
> 
> Uff, please not a static array.
> 
> > +
> > +#endif
> > +
> > +/**
> > + * ttm_resource_manager_debugfs_init - Setup debugfs entries for
> > specified
> > + * resource managers.
> > + * @bdev: The TTM device
> > + * @file_names: A mapping between TTM_TT placements and the
> > debugfs file
> > + * names
> > + * @num_file_names: The array size of @file_names.
> > + *
> > + * This function setups up debugfs files that can be used to look
> > + * at debug statistics of the specified ttm_resource_managers.
> > + * @file_names array is used to figure out which ttm placements
> > + * will get debugfs files created for them.
> > + */
> > +void
> > +ttm_resource_manager_debugfs_init(struct ttm_device *bdev,
> > +                               const char * const file_names[],
> > +                               uint32_t num_file_names)
> > +{
> > +#if defined(CONFIG_DEBUG_FS)
> > +     uint32_t i;
> > +     const struct file_operations *fops[] = {
> > +             &ttm_resource_manager0_fops,
> > +             &ttm_resource_manager1_fops,
> > +             &ttm_resource_manager2_fops,
> > +             &ttm_resource_manager3_fops,
> > +             &ttm_resource_manager4_fops,
> > +             &ttm_resource_manager5_fops,
> > +             &ttm_resource_manager6_fops,
> > +     };
> > +
> > +     WARN_ON(num_file_names > ARRAY_SIZE(fops));
> > +
> > +     for (i = 0; i < num_file_names; ++i)
> > +             if (file_names[i] && fops[i])
> > +                     debugfs_create_file(file_names[i], 0444,
> > +                                         ttm_debugfs_root, bdev,
> > fops[i]);
> 
> You can give the ttm_resource_manager directly as parameter here
> instead
> of the bdev and avoid the whole handling with the macro and global
> arrays.

We could but that does change the behaviour. I was trying to preserve
the old semantics. Because the lifetimes of driver specific managers
are not handled by ttm, there's nothing preventing the drivers from,
e.g. during reset, deleting the old and setting up new resource
managers. By always using ttm_manager_type() we make sure that we're
always using the current one. Passing ttm_resource_manager directly
makes it impossible to validate that at _show() time
ttm_resource_manager is still valid. It's not a problem for vmwgfx
because we never reset the resource managers but I didn't feel
comfortable changing the semantics like that for all drivers. It could
lead to weird crashes, but if you prefer that approach I'm happy to
change it.

z

Daniel Vetter April 8, 2022, 7:56 a.m. UTC | #3

On Thu, Apr 07, 2022 at 02:15:52PM +0000, Zack Rusin wrote:
> On Thu, 2022-04-07 at 08:01 +0200, Christian König wrote:
> > Am 07.04.22 um 04:56 schrieb Zack Rusin:
> > > From: Zack Rusin <[e-mail]>
> > > 
> > > Drivers duplicate the code required to add debugfs entries for
> > > various
> > > ttm resource managers. To fix it add common TTM resource manager
> > > code that each driver can reuse.
> > > 
> > > Because TTM resource managers can be initialized and set a lot
> > > later
> > > than TTM device initialization a seperate init function is
> > > required.
> > > Specific resource managers can overwrite
> > > ttm_resource_manager_func::debug to get more information from those
> > > debugfs entries.
> > > 
> > > Signed-off-by: Zack Rusin <[e-mail]>
> > > Cc: Christian Koenig <[e-mail]>
> > > Cc: Huang Rui <[e-mail]>
> > > Cc: David Airlie <[e-mail]>
> > > Cc: Daniel Vetter <[e-mail]>
> > 
> > Ah, yes that was on my TODO list for quite a while as well.
> > 
> > > ---
> > >   drivers/gpu/drm/ttm/ttm_resource.c | 65
> > > ++++++++++++++++++++++++++++++
> > >   include/drm/ttm/ttm_resource.h     |  4 ++
> > >   2 files changed, 69 insertions(+)
> > > 
> > > diff --git a/drivers/gpu/drm/ttm/ttm_resource.c
> > > b/drivers/gpu/drm/ttm/ttm_resource.c
> > > index 492ba3157e75..6392ad3e9a88 100644
> > > --- a/drivers/gpu/drm/ttm/ttm_resource.c
> > > +++ b/drivers/gpu/drm/ttm/ttm_resource.c
> > > @@ -29,6 +29,8 @@
> > >   #include <drm/ttm/ttm_resource.h>
> > >   #include <drm/ttm/ttm_bo_driver.h>
> > > 
> > > +#include "ttm_module.h"
> > > +
> > >   /**
> > >    * ttm_lru_bulk_move_init - initialize a bulk move structure
> > >    * @bulk: the structure to init
> > > @@ -644,3 +646,66 @@ ttm_kmap_iter_linear_io_fini(struct
> > > ttm_kmap_iter_linear_io *iter_io,
> > > 
> > >       ttm_mem_io_free(bdev, mem);
> > >   }
> > > +
> > > +#if defined(CONFIG_DEBUG_FS)
> > > +
> > > +#define TTM_RES_MAN_SHOW(i) \
> > > +     static int ttm_resource_manager##i##_show(struct seq_file *m,
> > > void *unused) \
> > > +     { \
> > > +             struct ttm_device *bdev = (struct ttm_device *)m-
> > > >private; \
> > > +             struct ttm_resource_manager *man =
> > > ttm_manager_type(bdev, i); \
> > > +             struct drm_printer p = drm_seq_file_printer(m); \
> > > +             ttm_resource_manager_debug(man, &p); \
> > > +             return 0; \
> > > +     }\
> > > +     DEFINE_SHOW_ATTRIBUTE(ttm_resource_manager##i)
> > > +
> > > +TTM_RES_MAN_SHOW(0);
> > > +TTM_RES_MAN_SHOW(1);
> > > +TTM_RES_MAN_SHOW(2);
> > > +TTM_RES_MAN_SHOW(3);
> > > +TTM_RES_MAN_SHOW(4);
> > > +TTM_RES_MAN_SHOW(5);
> > > +TTM_RES_MAN_SHOW(6);
> > 
> > Uff, please not a static array.
> > 
> > > +
> > > +#endif
> > > +
> > > +/**
> > > + * ttm_resource_manager_debugfs_init - Setup debugfs entries for
> > > specified
> > > + * resource managers.
> > > + * @bdev: The TTM device
> > > + * @file_names: A mapping between TTM_TT placements and the
> > > debugfs file
> > > + * names
> > > + * @num_file_names: The array size of @file_names.
> > > + *
> > > + * This function setups up debugfs files that can be used to look
> > > + * at debug statistics of the specified ttm_resource_managers.
> > > + * @file_names array is used to figure out which ttm placements
> > > + * will get debugfs files created for them.
> > > + */
> > > +void
> > > +ttm_resource_manager_debugfs_init(struct ttm_device *bdev,
> > > +                               const char * const file_names[],
> > > +                               uint32_t num_file_names)
> > > +{
> > > +#if defined(CONFIG_DEBUG_FS)
> > > +     uint32_t i;
> > > +     const struct file_operations *fops[] = {
> > > +             &ttm_resource_manager0_fops,
> > > +             &ttm_resource_manager1_fops,
> > > +             &ttm_resource_manager2_fops,
> > > +             &ttm_resource_manager3_fops,
> > > +             &ttm_resource_manager4_fops,
> > > +             &ttm_resource_manager5_fops,
> > > +             &ttm_resource_manager6_fops,
> > > +     };
> > > +
> > > +     WARN_ON(num_file_names > ARRAY_SIZE(fops));
> > > +
> > > +     for (i = 0; i < num_file_names; ++i)
> > > +             if (file_names[i] && fops[i])
> > > +                     debugfs_create_file(file_names[i], 0444,
> > > +                                         ttm_debugfs_root, bdev,
> > > fops[i]);
> > 
> > You can give the ttm_resource_manager directly as parameter here
> > instead
> > of the bdev and avoid the whole handling with the macro and global
> > arrays.
> 
> We could but that does change the behaviour. I was trying to preserve
> the old semantics. Because the lifetimes of driver specific managers
> are not handled by ttm, there's nothing preventing the drivers from,
> e.g. during reset, deleting the old and setting up new resource
> managers. By always using ttm_manager_type() we make sure that we're
> always using the current one. Passing ttm_resource_manager directly
> makes it impossible to validate that at _show() time
> ttm_resource_manager is still valid. It's not a problem for vmwgfx
> because we never reset the resource managers but I didn't feel
> comfortable changing the semantics like that for all drivers. It could
> lead to weird crashes, but if you prefer that approach I'm happy to
> change it.

Uh resetting resource managers during the lifetime of a drm_device sounds
very broken. I guess it's somewhat ok over suspend/resume or so when
userspace cannot access the driver, but even then it smells fishy.

Unless we have a driver doing that I don't think this is a use-case we
should support.
-Daniel

Christian König April 8, 2022, 8:34 a.m. UTC | #4

Am 08.04.22 um 09:56 schrieb Daniel Vetter:
> On Thu, Apr 07, 2022 at 02:15:52PM +0000, Zack Rusin wrote:
>> On Thu, 2022-04-07 at 08:01 +0200, Christian König wrote:
>>> Am 07.04.22 um 04:56 schrieb Zack Rusin:
>>>> From: Zack Rusin <[e-mail]>
>>>>
>>>> Drivers duplicate the code required to add debugfs entries for
>>>> various
>>>> ttm resource managers. To fix it add common TTM resource manager
>>>> code that each driver can reuse.
>>>>
>>>> Because TTM resource managers can be initialized and set a lot
>>>> later
>>>> than TTM device initialization a seperate init function is
>>>> required.
>>>> Specific resource managers can overwrite
>>>> ttm_resource_manager_func::debug to get more information from those
>>>> debugfs entries.
>>>>
>>>> Signed-off-by: Zack Rusin <[e-mail]>
>>>> Cc: Christian Koenig <[e-mail]>
>>>> Cc: Huang Rui <[e-mail]>
>>>> Cc: David Airlie <[e-mail]>
>>>> Cc: Daniel Vetter <[e-mail]>
>>> Ah, yes that was on my TODO list for quite a while as well.
>>>
>>>> ---
>>>>    drivers/gpu/drm/ttm/ttm_resource.c | 65
>>>> ++++++++++++++++++++++++++++++
>>>>    include/drm/ttm/ttm_resource.h     |  4 ++
>>>>    2 files changed, 69 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/ttm/ttm_resource.c
>>>> b/drivers/gpu/drm/ttm/ttm_resource.c
>>>> index 492ba3157e75..6392ad3e9a88 100644
>>>> --- a/drivers/gpu/drm/ttm/ttm_resource.c
>>>> +++ b/drivers/gpu/drm/ttm/ttm_resource.c
>>>> @@ -29,6 +29,8 @@
>>>>    #include <drm/ttm/ttm_resource.h>
>>>>    #include <drm/ttm/ttm_bo_driver.h>
>>>>
>>>> +#include "ttm_module.h"
>>>> +
>>>>    /**
>>>>     * ttm_lru_bulk_move_init - initialize a bulk move structure
>>>>     * @bulk: the structure to init
>>>> @@ -644,3 +646,66 @@ ttm_kmap_iter_linear_io_fini(struct
>>>> ttm_kmap_iter_linear_io *iter_io,
>>>>
>>>>        ttm_mem_io_free(bdev, mem);
>>>>    }
>>>> +
>>>> +#if defined(CONFIG_DEBUG_FS)
>>>> +
>>>> +#define TTM_RES_MAN_SHOW(i) \
>>>> +     static int ttm_resource_manager##i##_show(struct seq_file *m,
>>>> void *unused) \
>>>> +     { \
>>>> +             struct ttm_device *bdev = (struct ttm_device *)m-
>>>>> private; \
>>>> +             struct ttm_resource_manager *man =
>>>> ttm_manager_type(bdev, i); \
>>>> +             struct drm_printer p = drm_seq_file_printer(m); \
>>>> +             ttm_resource_manager_debug(man, &p); \
>>>> +             return 0; \
>>>> +     }\
>>>> +     DEFINE_SHOW_ATTRIBUTE(ttm_resource_manager##i)
>>>> +
>>>> +TTM_RES_MAN_SHOW(0);
>>>> +TTM_RES_MAN_SHOW(1);
>>>> +TTM_RES_MAN_SHOW(2);
>>>> +TTM_RES_MAN_SHOW(3);
>>>> +TTM_RES_MAN_SHOW(4);
>>>> +TTM_RES_MAN_SHOW(5);
>>>> +TTM_RES_MAN_SHOW(6);
>>> Uff, please not a static array.
>>>
>>>> +
>>>> +#endif
>>>> +
>>>> +/**
>>>> + * ttm_resource_manager_debugfs_init - Setup debugfs entries for
>>>> specified
>>>> + * resource managers.
>>>> + * @bdev: The TTM device
>>>> + * @file_names: A mapping between TTM_TT placements and the
>>>> debugfs file
>>>> + * names
>>>> + * @num_file_names: The array size of @file_names.
>>>> + *
>>>> + * This function setups up debugfs files that can be used to look
>>>> + * at debug statistics of the specified ttm_resource_managers.
>>>> + * @file_names array is used to figure out which ttm placements
>>>> + * will get debugfs files created for them.
>>>> + */
>>>> +void
>>>> +ttm_resource_manager_debugfs_init(struct ttm_device *bdev,
>>>> +                               const char * const file_names[],
>>>> +                               uint32_t num_file_names)
>>>> +{
>>>> +#if defined(CONFIG_DEBUG_FS)
>>>> +     uint32_t i;
>>>> +     const struct file_operations *fops[] = {
>>>> +             &ttm_resource_manager0_fops,
>>>> +             &ttm_resource_manager1_fops,
>>>> +             &ttm_resource_manager2_fops,
>>>> +             &ttm_resource_manager3_fops,
>>>> +             &ttm_resource_manager4_fops,
>>>> +             &ttm_resource_manager5_fops,
>>>> +             &ttm_resource_manager6_fops,
>>>> +     };
>>>> +
>>>> +     WARN_ON(num_file_names > ARRAY_SIZE(fops));
>>>> +
>>>> +     for (i = 0; i < num_file_names; ++i)
>>>> +             if (file_names[i] && fops[i])
>>>> +                     debugfs_create_file(file_names[i], 0444,
>>>> +                                         ttm_debugfs_root, bdev,
>>>> fops[i]);
>>> You can give the ttm_resource_manager directly as parameter here
>>> instead
>>> of the bdev and avoid the whole handling with the macro and global
>>> arrays.
>> We could but that does change the behaviour. I was trying to preserve
>> the old semantics. Because the lifetimes of driver specific managers
>> are not handled by ttm, there's nothing preventing the drivers from,
>> e.g. during reset, deleting the old and setting up new resource
>> managers. By always using ttm_manager_type() we make sure that we're
>> always using the current one. Passing ttm_resource_manager directly
>> makes it impossible to validate that at _show() time
>> ttm_resource_manager is still valid. It's not a problem for vmwgfx
>> because we never reset the resource managers but I didn't feel
>> comfortable changing the semantics like that for all drivers. It could
>> lead to weird crashes, but if you prefer that approach I'm happy to
>> change it.
> Uh resetting resource managers during the lifetime of a drm_device sounds
> very broken. I guess it's somewhat ok over suspend/resume or so when
> userspace cannot access the driver, but even then it smells fishy.
>
> Unless we have a driver doing that I don't think this is a use-case we
> should support.

Yes, completely agree.

We often use the placement enum only because it used to be a flag and 
I'm working on to get rid of that and use a pointer to the manager where 
an allocation comes from directly.

Regards,
Christian.

> -Daniel

Patch

diff --git a/drivers/gpu/drm/ttm/ttm_resource.c b/drivers/gpu/drm/ttm/ttm_resource.c
index 492ba3157e75..6392ad3e9a88 100644
--- a/drivers/gpu/drm/ttm/ttm_resource.c
+++ b/drivers/gpu/drm/ttm/ttm_resource.c
@@ -29,6 +29,8 @@ 
 #include <drm/ttm/ttm_resource.h>
 #include <drm/ttm/ttm_bo_driver.h>
 
+#include "ttm_module.h"
+
 /**
  * ttm_lru_bulk_move_init - initialize a bulk move structure
  * @bulk: the structure to init
@@ -644,3 +646,66 @@  ttm_kmap_iter_linear_io_fini(struct ttm_kmap_iter_linear_io *iter_io,
 
 	ttm_mem_io_free(bdev, mem);
 }
+
+#if defined(CONFIG_DEBUG_FS)
+
+#define TTM_RES_MAN_SHOW(i) \
+	static int ttm_resource_manager##i##_show(struct seq_file *m, void *unused) \
+	{ \
+		struct ttm_device *bdev = (struct ttm_device *)m->private; \
+		struct ttm_resource_manager *man = ttm_manager_type(bdev, i); \
+		struct drm_printer p = drm_seq_file_printer(m); \
+		ttm_resource_manager_debug(man, &p); \
+		return 0; \
+	}\
+	DEFINE_SHOW_ATTRIBUTE(ttm_resource_manager##i)
+
+TTM_RES_MAN_SHOW(0);
+TTM_RES_MAN_SHOW(1);
+TTM_RES_MAN_SHOW(2);
+TTM_RES_MAN_SHOW(3);
+TTM_RES_MAN_SHOW(4);
+TTM_RES_MAN_SHOW(5);
+TTM_RES_MAN_SHOW(6);
+
+#endif
+
+/**
+ * ttm_resource_manager_debugfs_init - Setup debugfs entries for specified
+ * resource managers.
+ * @bdev: The TTM device
+ * @file_names: A mapping between TTM_TT placements and the debugfs file
+ * names
+ * @num_file_names: The array size of @file_names.
+ *
+ * This function setups up debugfs files that can be used to look
+ * at debug statistics of the specified ttm_resource_managers.
+ * @file_names array is used to figure out which ttm placements
+ * will get debugfs files created for them.
+ */
+void
+ttm_resource_manager_debugfs_init(struct ttm_device *bdev,
+				  const char * const file_names[],
+				  uint32_t num_file_names)
+{
+#if defined(CONFIG_DEBUG_FS)
+	uint32_t i;
+	const struct file_operations *fops[] = {
+		&ttm_resource_manager0_fops,
+		&ttm_resource_manager1_fops,
+		&ttm_resource_manager2_fops,
+		&ttm_resource_manager3_fops,
+		&ttm_resource_manager4_fops,
+		&ttm_resource_manager5_fops,
+		&ttm_resource_manager6_fops,
+	};
+
+	WARN_ON(num_file_names > ARRAY_SIZE(fops));
+
+	for (i = 0; i < num_file_names; ++i)
+		if (file_names[i] && fops[i])
+			debugfs_create_file(file_names[i], 0444,
+					    ttm_debugfs_root, bdev, fops[i]);
+#endif
+}
+EXPORT_SYMBOL(ttm_resource_manager_debugfs_init);
diff --git a/include/drm/ttm/ttm_resource.h b/include/drm/ttm/ttm_resource.h
index 4428a62e5f0e..3c85cdd21ca5 100644
--- a/include/drm/ttm/ttm_resource.h
+++ b/include/drm/ttm/ttm_resource.h
@@ -383,4 +383,8 @@  ttm_kmap_iter_linear_io_init(struct ttm_kmap_iter_linear_io *iter_io,
 void ttm_kmap_iter_linear_io_fini(struct ttm_kmap_iter_linear_io *iter_io,
 				  struct ttm_device *bdev,
 				  struct ttm_resource *mem);
+
+void ttm_resource_manager_debugfs_init(struct ttm_device *bdev,
+				       const char * const file_name[],
+				       uint32_t num_file_names);
 #endif