Am 16.03.22 um 14:19 schrieb Robert Beckett:
>
>
> On 16/03/2022 09:54, Christian König wrote:
>> Am 15.03.22 um 19:04 schrieb Robert Beckett:
>>> RFC: do we want this to become a generic interface in
>>> ttm_resource_manager_func?
>>>
>>> RFC: would we prefer a different interface? e.g.
>>> for_each_resource_in_range or for_each_bo_in_range
>>
>> Well completely NAK to that. Why do you need that?
>>
>> The long term goal is to completely remove the range checks from TTM
>> instead.
>
> ah, I did not know that.
> I wanted it just to enable parity with a selftest that checks whether
> a range is allocated before initializing a given range with test data
> behind the allocator's back. It needs to check the range so that it
> doesn't destroy in use data.
Mhm, of hand that doesn't sounds like a valid test case. Do you have the
code at hand?
>
> I suppose we could add another drm_mm range tracker just for testing
> and shadow track each allocation in the range, but that seemed like a
> lot of extra infrastructure for no general runtime use.
I have no idea what you mean with that.
>
> would you mind explaining the rationale for removing range checks? It
> seems to me like a natural fit for a memory manager
TTM manages buffer objects and resources, not address space. The
lpfn/fpfn parameter for the resource allocators are actually used as
just two independent parameters and not define any range. We just keep
the names for historical reasons.
The only places we still use and compare them as ranges are
ttm_resource_compat() and ttm_bo_eviction_valuable() and I already have
patches to clean up those and move them into the backend resource handling.
Regards,
Christian.
>
>>
>> Regards,
>> Christian.
>>
>>>
>>> Signed-off-by: Robert Beckett <[email protected]>
>>> ---
>>> drivers/gpu/drm/ttm/ttm_range_manager.c | 21 +++++++++++++++++++++
>>> include/drm/ttm/ttm_range_manager.h | 3 +++
>>> 2 files changed, 24 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/ttm/ttm_range_manager.c
>>> b/drivers/gpu/drm/ttm/ttm_range_manager.c
>>> index 8cd4f3fb9f79..5662627bb933 100644
>>> --- a/drivers/gpu/drm/ttm/ttm_range_manager.c
>>> +++ b/drivers/gpu/drm/ttm/ttm_range_manager.c
>>> @@ -206,3 +206,24 @@ int ttm_range_man_fini_nocheck(struct
>>> ttm_device *bdev,
>>> return 0;
>>> }
>>> EXPORT_SYMBOL(ttm_range_man_fini_nocheck);
>>> +
>>> +/**
>>> + * ttm_range_man_range_busy - Check whether anything is allocated
>>> with a range
>>> + *
>>> + * @man: memory manager to check
>>> + * @fpfn: first page number to check
>>> + * @lpfn: last page number to check
>>> + *
>>> + * Return: true if anything allocated within the range, false
>>> otherwise.
>>> + */
>>> +bool ttm_range_man_range_busy(struct ttm_resource_manager *man,
>>> + unsigned fpfn, unsigned lpfn)
>>> +{
>>> + struct ttm_range_manager *rman = to_range_manager(man);
>>> + struct drm_mm *mm = &rman->mm;
>>> +
>>> + if (__drm_mm_interval_first(mm, PFN_PHYS(fpfn), PFN_PHYS(lpfn +
>>> 1) - 1))
>>> + return true;
>>> + return false;
>>> +}
>>> +EXPORT_SYMBOL(ttm_range_man_range_busy);
>>> diff --git a/include/drm/ttm/ttm_range_manager.h
>>> b/include/drm/ttm/ttm_range_manager.h
>>> index 7963b957e9ef..86794a3f9101 100644
>>> --- a/include/drm/ttm/ttm_range_manager.h
>>> +++ b/include/drm/ttm/ttm_range_manager.h
>>> @@ -53,4 +53,7 @@ static __always_inline int
>>> ttm_range_man_fini(struct ttm_device *bdev,
>>> BUILD_BUG_ON(__builtin_constant_p(type) && type >=
>>> TTM_NUM_MEM_TYPES);
>>> return ttm_range_man_fini_nocheck(bdev, type);
>>> }
>>> +
>>> +bool ttm_range_man_range_busy(struct ttm_resource_manager *man,
>>> + unsigned fpfn, unsigned lpfn);
>>> #endif
>>
On 16/03/2022 13:43, Christian König wrote:
> Am 16.03.22 um 14:19 schrieb Robert Beckett:
>>
>>
>> On 16/03/2022 09:54, Christian König wrote:
>>> Am 15.03.22 um 19:04 schrieb Robert Beckett:
>>>> RFC: do we want this to become a generic interface in
>>>> ttm_resource_manager_func?
>>>>
>>>> RFC: would we prefer a different interface? e.g.
>>>> for_each_resource_in_range or for_each_bo_in_range
>>>
>>> Well completely NAK to that. Why do you need that?
>>>
>>> The long term goal is to completely remove the range checks from TTM
>>> instead.
>>
>> ah, I did not know that.
>> I wanted it just to enable parity with a selftest that checks whether
>> a range is allocated before initializing a given range with test data
>> behind the allocator's back. It needs to check the range so that it
>> doesn't destroy in use data.
>
> Mhm, of hand that doesn't sounds like a valid test case. Do you have the
> code at hand?
https://patchwork.freedesktop.org/patch/478347/?series=101396&rev=1
this is where I replace an existing range check via drm_mm with the
range check I added in this patch.
>
>>
>> I suppose we could add another drm_mm range tracker just for testing
>> and shadow track each allocation in the range, but that seemed like a
>> lot of extra infrastructure for no general runtime use.
>
> I have no idea what you mean with that.
I meant as a potential solution to tracking allocations without a range
check, we would need to add something external. e.g. adding a shadow
drm_mm range tracker, or a bitmask across the range, or stick objects in
a list etc.
>
>>
>> would you mind explaining the rationale for removing range checks? It
>> seems to me like a natural fit for a memory manager
>
> TTM manages buffer objects and resources, not address space. The
> lpfn/fpfn parameter for the resource allocators are actually used as
> just two independent parameters and not define any range. We just keep
> the names for historical reasons.
>
> The only places we still use and compare them as ranges are
> ttm_resource_compat() and ttm_bo_eviction_valuable() and I already have
> patches to clean up those and move them into the backend resource handling.
except the ttm_range_manager seems to still use them as a range specifier.
If the general design going forward is to not consider ranges, how would
you recommend constructing buffers around pre-allocated regions e.g.
uefi frame buffers who's range is dictated externally?
>
> Regards,
> Christian.
>
>>
>>>
>>> Regards,
>>> Christian.
>>>
>>>>
>>>> Signed-off-by: Robert Beckett <[email protected]>
>>>> ---
>>>> drivers/gpu/drm/ttm/ttm_range_manager.c | 21 +++++++++++++++++++++
>>>> include/drm/ttm/ttm_range_manager.h | 3 +++
>>>> 2 files changed, 24 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/ttm/ttm_range_manager.c
>>>> b/drivers/gpu/drm/ttm/ttm_range_manager.c
>>>> index 8cd4f3fb9f79..5662627bb933 100644
>>>> --- a/drivers/gpu/drm/ttm/ttm_range_manager.c
>>>> +++ b/drivers/gpu/drm/ttm/ttm_range_manager.c
>>>> @@ -206,3 +206,24 @@ int ttm_range_man_fini_nocheck(struct
>>>> ttm_device *bdev,
>>>> return 0;
>>>> }
>>>> EXPORT_SYMBOL(ttm_range_man_fini_nocheck);
>>>> +
>>>> +/**
>>>> + * ttm_range_man_range_busy - Check whether anything is allocated
>>>> with a range
>>>> + *
>>>> + * @man: memory manager to check
>>>> + * @fpfn: first page number to check
>>>> + * @lpfn: last page number to check
>>>> + *
>>>> + * Return: true if anything allocated within the range, false
>>>> otherwise.
>>>> + */
>>>> +bool ttm_range_man_range_busy(struct ttm_resource_manager *man,
>>>> + unsigned fpfn, unsigned lpfn)
>>>> +{
>>>> + struct ttm_range_manager *rman = to_range_manager(man);
>>>> + struct drm_mm *mm = &rman->mm;
>>>> +
>>>> + if (__drm_mm_interval_first(mm, PFN_PHYS(fpfn), PFN_PHYS(lpfn +
>>>> 1) - 1))
>>>> + return true;
>>>> + return false;
>>>> +}
>>>> +EXPORT_SYMBOL(ttm_range_man_range_busy);
>>>> diff --git a/include/drm/ttm/ttm_range_manager.h
>>>> b/include/drm/ttm/ttm_range_manager.h
>>>> index 7963b957e9ef..86794a3f9101 100644
>>>> --- a/include/drm/ttm/ttm_range_manager.h
>>>> +++ b/include/drm/ttm/ttm_range_manager.h
>>>> @@ -53,4 +53,7 @@ static __always_inline int
>>>> ttm_range_man_fini(struct ttm_device *bdev,
>>>> BUILD_BUG_ON(__builtin_constant_p(type) && type >=
>>>> TTM_NUM_MEM_TYPES);
>>>> return ttm_range_man_fini_nocheck(bdev, type);
>>>> }
>>>> +
>>>> +bool ttm_range_man_range_busy(struct ttm_resource_manager *man,
>>>> + unsigned fpfn, unsigned lpfn);
>>>> #endif
>>>
>