[Intel-gfx] [PATCH v4 2/6] drm: improve drm_buddy_alloc function

[Thomas Zimmermann]

Hi

Am 03.01.22 um 08:41 schrieb Christian König:
> 
> 
> Am 26.12.21 um 21:59 schrieb Arunpravin:
>> Hi Thomas
>>
>> On 16/12/21 5:05 pm, Thomas Zimmermann wrote:
>>> Hi
>>>
>>> Am 01.12.21 um 17:39 schrieb Arunpravin:
>>>> - Make drm_buddy_alloc a single function to handle
>>>>     range allocation and non-range allocation demands
>>>>
>>>> - Implemented a new function alloc_range() which allocates
>>>>     the requested power-of-two block comply with range limitations
>>>>
>>>> - Moved order computation and memory alignment logic from
>>>>     i915 driver to drm buddy
>>>>
>>>> v2:
>>>>     merged below changes to keep the build unbroken
>>>>      - drm_buddy_alloc_range() becomes obsolete and may be removed
>>>>      - enable ttm range allocation (fpfn / lpfn) support in i915 driver
>>>>      - apply enhanced drm_buddy_alloc() function to i915 driver
>>>>
>>>> v3(Matthew Auld):
>>>>     - Fix alignment issues and remove unnecessary list_empty check
>>>>     - add more validation checks for input arguments
>>>>     - make alloc_range() block allocations as bottom-up
>>>>     - optimize order computation logic
>>>>     - replace uint64_t with u64, which is preferred in the kernel
>>>>
>>>> v4(Matthew Auld):
>>>>     - keep drm_buddy_alloc_range() function implementation for generic
>>>>       actual range allocations
>>>>     - keep alloc_range() implementation for end bias allocations
>>>>
>>>> Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam at amd.com>
>> <SNIP>
>>
>>>> +#define DRM_BUDDY_RANGE_ALLOCATION (1 << 0)
>>>> +
>>>>    struct drm_buddy_block {
>>>>    #define DRM_BUDDY_HEADER_OFFSET GENMASK_ULL(63, 12)
>>>>    #define DRM_BUDDY_HEADER_STATE  GENMASK_ULL(11, 10)
>>>> @@ -132,12 +139,11 @@ int drm_buddy_init(struct drm_buddy_mm *mm, 
>>>> u64 size, u64 chunk_size);
>>>>    void drm_buddy_fini(struct drm_buddy_mm *mm);
>>>> -struct drm_buddy_block *
>>>> -drm_buddy_alloc(struct drm_buddy_mm *mm, unsigned int order);
>>> Just a style issue. The structure is called drm_buddy_mm. For
>>> consistency, I like to suggest to name all the public interfaces and
>>> defines drm_buddy_mm_* instead of just drm_buddy_*.
>>>
>> Thanks for the suggestion, I think renaming drm_buddy_* to
>> drm_buddy_mm_* creates a long name for the public interfaces, for
>> instance - drm_buddy_mm_alloc_blocks(),
>> discussing the style issue internally
>> @Matthew, @christian - please let me know your opinion
> 
> I would prefer drm_buddy as prefix as well and I think we could rather 
> drop the _mm postfix from the structure here.

I was mostly concerned about mismatching names for functions and 
structures. If drm_buddy_ (without mm) for all naming is preferred, I 
wouldn't mind.

Best regards
Thomas

> 
> Cause what we try to manage is not necessary memory, but rather address 
> space.
> 
> Christian.
> 
>>
>>>> -
>>>> -int drm_buddy_alloc_range(struct drm_buddy_mm *mm,
>>>> -              struct list_head *blocks,
>>>> -              u64 start, u64 size);
>>>> +int drm_buddy_alloc(struct drm_buddy_mm *mm,
>>>> +            u64 start, u64 end, u64 size,
>>>> +            u64 min_page_size,
>>>> +            struct list_head *blocks,
>>>> +            unsigned long flags);
>>>>    void drm_buddy_free(struct drm_buddy_mm *mm, struct 
>>>> drm_buddy_block *block);
>>> I'd call those *_alloc_blocks() and _free_blocks(). Right now it sounds
>>> as if they allocate and free instances of drm_buddy_mm.
>> can we call those drm_buddy_alloc_blocks() and drm_buddy_free_blocks()
>> Does this make sense?
>>> Best regards
>>> Thomas
>>>>
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
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