Re: [PATCH 02/10] drm/ttm: flip over the range manager to self allocated nodes

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

Am 02.06.21 um 20:52 schrieb Thomas Hellström (Intel):
>
> On 6/2/21 8:41 PM, Christian König wrote:
>> Am 02.06.21 um 17:28 schrieb Thomas Hellström (Intel):
>>> Hi!
>>>
>>> On 6/2/21 4:17 PM, Christian König wrote:
>>>> Am 02.06.21 um 16:13 schrieb Thomas Hellström (Intel):
>>>>>
>>>>> On 6/2/21 3:07 PM, Christian König wrote:
>>>>>>
>>>>>>
>>>>>> Am 02.06.21 um 14:33 schrieb Thomas Hellström (Intel):
>>>>>>>
>>>>>>> On 6/2/21 2:11 PM, Christian König wrote:
>>>>>>>> Am 02.06.21 um 13:44 schrieb Thomas Hellström (Intel):
>>>>>>>>>
>>>>>>>>> On 6/2/21 12:09 PM, Christian König wrote:
>>>>>>>>>> Start with the range manager to make the resource object the 
>>>>>>>>>> base
>>>>>>>>>> class for the allocated nodes.
>>>>>>>>>>
>>>>>>>>>> While at it cleanup a lot of the code around that.
>>>>>>>>>>
>>>>>>>>>> Signed-off-by: Christian König <christian.koenig@amd.com>
>>>>>>>>>> Reviewed-by: Matthew Auld <matthew.auld@intel.com>
>>>>>>>>>> ---
>>>>>>>>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c |  1 +
>>>>>>>>>>   drivers/gpu/drm/drm_gem_vram_helper.c   |  2 +
>>>>>>>>>>   drivers/gpu/drm/nouveau/nouveau_ttm.c   |  2 +
>>>>>>>>>>   drivers/gpu/drm/qxl/qxl_ttm.c           |  1 +
>>>>>>>>>>   drivers/gpu/drm/radeon/radeon_ttm.c     |  1 +
>>>>>>>>>>   drivers/gpu/drm/ttm/ttm_range_manager.c | 56 
>>>>>>>>>> ++++++++++++++++++-------
>>>>>>>>>>   drivers/gpu/drm/ttm/ttm_resource.c      | 26 ++++++++----
>>>>>>>>>>   include/drm/ttm/ttm_bo_driver.h         | 26 ------------
>>>>>>>>>>   include/drm/ttm/ttm_range_manager.h     | 43 
>>>>>>>>>> +++++++++++++++++++
>>>>>>>>>>   include/drm/ttm/ttm_resource.h          |  3 ++
>>>>>>>>>>   10 files changed, 111 insertions(+), 50 deletions(-)
>>>>>>>>>>   create mode 100644 include/drm/ttm/ttm_range_manager.h
>>>>>>>>>>
>>>>>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c 
>>>>>>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>>>>>>>> index 69db89261650..df1f185faae9 100644
>>>>>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>>>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>>>>>>>> @@ -45,6 +45,7 @@
>>>>>>>>>>   #include <drm/ttm/ttm_bo_api.h>
>>>>>>>>>>   #include <drm/ttm/ttm_bo_driver.h>
>>>>>>>>>>   #include <drm/ttm/ttm_placement.h>
>>>>>>>>>> +#include <drm/ttm/ttm_range_manager.h>
>>>>>>>>>>     #include <drm/amdgpu_drm.h>
>>>>>>>>>>   diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c 
>>>>>>>>>> b/drivers/gpu/drm/drm_gem_vram_helper.c
>>>>>>>>>> index 83e7258c7f90..17a4c5d47b6a 100644
>>>>>>>>>> --- a/drivers/gpu/drm/drm_gem_vram_helper.c
>>>>>>>>>> +++ b/drivers/gpu/drm/drm_gem_vram_helper.c
>>>>>>>>>> @@ -17,6 +17,8 @@
>>>>>>>>>>   #include <drm/drm_prime.h>
>>>>>>>>>>   #include <drm/drm_simple_kms_helper.h>
>>>>>>>>>>   +#include <drm/ttm/ttm_range_manager.h>
>>>>>>>>>> +
>>>>>>>>>>   static const struct drm_gem_object_funcs 
>>>>>>>>>> drm_gem_vram_object_funcs;
>>>>>>>>>>     /**
>>>>>>>>>> diff --git a/drivers/gpu/drm/nouveau/nouveau_ttm.c 
>>>>>>>>>> b/drivers/gpu/drm/nouveau/nouveau_ttm.c
>>>>>>>>>> index 65430912ff72..b08b8efeefba 100644
>>>>>>>>>> --- a/drivers/gpu/drm/nouveau/nouveau_ttm.c
>>>>>>>>>> +++ b/drivers/gpu/drm/nouveau/nouveau_ttm.c
>>>>>>>>>> @@ -26,6 +26,8 @@
>>>>>>>>>>   #include <linux/limits.h>
>>>>>>>>>>   #include <linux/swiotlb.h>
>>>>>>>>>>   +#include <drm/ttm/ttm_range_manager.h>
>>>>>>>>>> +
>>>>>>>>>>   #include "nouveau_drv.h"
>>>>>>>>>>   #include "nouveau_gem.h"
>>>>>>>>>>   #include "nouveau_mem.h"
>>>>>>>>>> diff --git a/drivers/gpu/drm/qxl/qxl_ttm.c 
>>>>>>>>>> b/drivers/gpu/drm/qxl/qxl_ttm.c
>>>>>>>>>> index 8aa87b8edb9c..19fd39d9a00c 100644
>>>>>>>>>> --- a/drivers/gpu/drm/qxl/qxl_ttm.c
>>>>>>>>>> +++ b/drivers/gpu/drm/qxl/qxl_ttm.c
>>>>>>>>>> @@ -32,6 +32,7 @@
>>>>>>>>>>   #include <drm/ttm/ttm_bo_api.h>
>>>>>>>>>>   #include <drm/ttm/ttm_bo_driver.h>
>>>>>>>>>>   #include <drm/ttm/ttm_placement.h>
>>>>>>>>>> +#include <drm/ttm/ttm_range_manager.h>
>>>>>>>>>>     #include "qxl_drv.h"
>>>>>>>>>>   #include "qxl_object.h"
>>>>>>>>>> diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c 
>>>>>>>>>> b/drivers/gpu/drm/radeon/radeon_ttm.c
>>>>>>>>>> index cdffa9b65108..ad2a5a791bba 100644
>>>>>>>>>> --- a/drivers/gpu/drm/radeon/radeon_ttm.c
>>>>>>>>>> +++ b/drivers/gpu/drm/radeon/radeon_ttm.c
>>>>>>>>>> @@ -45,6 +45,7 @@
>>>>>>>>>>   #include <drm/ttm/ttm_bo_api.h>
>>>>>>>>>>   #include <drm/ttm/ttm_bo_driver.h>
>>>>>>>>>>   #include <drm/ttm/ttm_placement.h>
>>>>>>>>>> +#include <drm/ttm/ttm_range_manager.h>
>>>>>>>>>>     #include "radeon_reg.h"
>>>>>>>>>>   #include "radeon.h"
>>>>>>>>>> diff --git a/drivers/gpu/drm/ttm/ttm_range_manager.c 
>>>>>>>>>> b/drivers/gpu/drm/ttm/ttm_range_manager.c
>>>>>>>>>> index b9d5da6e6a81..ce5d07ca384c 100644
>>>>>>>>>> --- a/drivers/gpu/drm/ttm/ttm_range_manager.c
>>>>>>>>>> +++ b/drivers/gpu/drm/ttm/ttm_range_manager.c
>>>>>>>>>> @@ -29,12 +29,13 @@
>>>>>>>>>>    * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
>>>>>>>>>>    */
>>>>>>>>>>   -#include <drm/ttm/ttm_bo_driver.h>
>>>>>>>>>> +#include <drm/ttm/ttm_device.h>
>>>>>>>>>>   #include <drm/ttm/ttm_placement.h>
>>>>>>>>>> +#include <drm/ttm/ttm_range_manager.h>
>>>>>>>>>> +#include <drm/ttm/ttm_bo_api.h>
>>>>>>>>>>   #include <drm/drm_mm.h>
>>>>>>>>>>   #include <linux/slab.h>
>>>>>>>>>>   #include <linux/spinlock.h>
>>>>>>>>>> -#include <linux/module.h>
>>>>>>>>>>     /*
>>>>>>>>>>    * Currently we use a spinlock for the lock, but a mutex 
>>>>>>>>>> *may* be
>>>>>>>>>> @@ -60,8 +61,8 @@ static int ttm_range_man_alloc(struct 
>>>>>>>>>> ttm_resource_manager *man,
>>>>>>>>>>                      struct ttm_resource *mem)
>>>>>>>>>>   {
>>>>>>>>>>       struct ttm_range_manager *rman = to_range_manager(man);
>>>>>>>>>> +    struct ttm_range_mgr_node *node;
>>>>>>>>>>       struct drm_mm *mm = &rman->mm;
>>>>>>>>>> -    struct drm_mm_node *node;
>>>>>>>>>>       enum drm_mm_insert_mode mode;
>>>>>>>>>>       unsigned long lpfn;
>>>>>>>>>>       int ret;
>>>>>>>>>> @@ -70,7 +71,7 @@ static int ttm_range_man_alloc(struct 
>>>>>>>>>> ttm_resource_manager *man,
>>>>>>>>>>       if (!lpfn)
>>>>>>>>>>           lpfn = man->size;
>>>>>>>>>>   -    node = kzalloc(sizeof(*node), GFP_KERNEL);
>>>>>>>>>> +    node = kzalloc(struct_size(node, mm_nodes, 1), GFP_KERNEL);
>>>>>>>>>
>>>>>>>>> I'm still a bit confused  about the situation where a driver 
>>>>>>>>> wants to attach private data to a struct ttm_resource without 
>>>>>>>>> having to re-implement its own range manager?
>>>>>>>>>
>>>>>>>>> Could be cached sg-tables, list of GPU bindings etc. Wouldn't 
>>>>>>>>> work with the above unless we have a void *driver_private 
>>>>>>>>> member on the struct ttm_resource. Is that the plan going 
>>>>>>>>> forward here? Or that the driver actually does the 
>>>>>>>>> re-implementation?
>>>>>>>>
>>>>>>>> I don't really understand your concern here. The basic idea is 
>>>>>>>> that drivers use ttm_resource as a base class for their own 
>>>>>>>> implementation.
>>>>>>>>
>>>>>>>> See for example how nouveau does that:
>>>>>>>>
>>>>>>>> struct nouveau_mem {
>>>>>>>>         struct ttm_resource base;
>>>>>>>>         struct nouveau_cli *cli;
>>>>>>>>         u8 kind;
>>>>>>>>         u8 comp;
>>>>>>>>         struct nvif_mem mem;
>>>>>>>>         struct nvif_vma vma[2];
>>>>>>>> };
>>>>>>>>
>>>>>>>> The range manager is helping driver specific resource managers 
>>>>>>>> which want to implement something drm_mm_nodes based. E.g. 
>>>>>>>> amdgpu_gtt_mgr and amdgpu_vram_mgr, but it can also be used 
>>>>>>>> stand alone.
>>>>>>>>
>>>>>>>> The ttm_range_mgr_node can then be used as base class for this 
>>>>>>>> functionality. I already want to move some more code from 
>>>>>>>> amdgpu_vram_mgr.c into the range manager, but that is just 
>>>>>>>> minor cleanup work.
>>>>>>>>
>>>>>>> Sure but if you embed a ttm_range_mgr_node in your struct 
>>>>>>> i915_resource, and wanted to use the ttm range manager for it, 
>>>>>>> it would allocate a struct ttm_range_mgr_node rather than a 
>>>>>>> struct i915_resource? Or am I missing something?
>>>>>>
>>>>>> Yes, that's the general idea I'm targeting for. I'm just not 
>>>>>> fully there yet.
>>>>>
>>>>> Hmm, I don't fully understand the reply, I described a buggy 
>>>>> scenario and you replied that's what we're targeting for?
>>>>
>>>> Ok, I don't seem to understand what you mean here. What is buggy on 
>>>> that?
>>>
>>> The buggy thing I'm trying to describe is a scenario where I want to 
>>> have a struct i915_ttm_resource which embeds a struct 
>>> ttm_range_mgr_node, but there is no way I can tell the generic ttm 
>>> range manager to allocate a struct i915_ttm_resource instead of a 
>>> struct ttm_range_mgr_node.
>>>
>>> So what I want to be able to do: I have
>>>
>>> struct i915_ttm_resource {
>>>         struct i915_gpu_bindings gpu_bindings;
>>>         struct ttm_range_mgr_node range_node;
>>> };
>>>
>>> Now I want to be able to share common code as much as possible and 
>>> use the generic ttm_range_manager here. How would I go about doing 
>>> that with the proposed changes?
>>
>> Ah, yes that is the part I haven't moved over yet. In other words 
>> that is not possible yet.
>
> OK, that "yet" sounds good. So this will be possible moving forward? 
> (Basically it's the overall design that's not completely clear to me 
> yet, not really the code itself)

Yes, absolutely.

Christian.

>
> Thanks,
>
> Thomas
>
>