[PATCH v6 2/6] drm: improve drm_buddy_alloc function
Arunpravin
arunpravin.paneerselvam at amd.com
Thu Jan 6 21:23:08 UTC 2022
> -----Original Message-----
> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Matthew Auld
> Sent: Tuesday, January 4, 2022 7:32 PM
> To: Paneer Selvam, Arunpravin <Arunpravin.PaneerSelvam at amd.com>; dri-devel at lists.freedesktop.org; intel-gfx at lists.freedesktop.org; amd-gfx at lists.freedesktop.org
> Cc: Deucher, Alexander <Alexander.Deucher at amd.com>; tzimmermann at suse.de; jani.nikula at linux.intel.com; Koenig, Christian <Christian.Koenig at amd.com>; daniel at ffwll.ch
> Subject: Re: [PATCH v6 2/6] drm: improve drm_buddy_alloc function
>
> On 26/12/2021 22:24, Arunpravin wrote:
>> - 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>
>
>> @@ -73,34 +83,16 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
>>
>> n_pages = size >> ilog2(mm->chunk_size);
>>
>> - do {
>> - struct drm_buddy_block *block;
>> - unsigned int order;
>> -
>> - order = fls(n_pages) - 1;
>> - GEM_BUG_ON(order > mm->max_order);
>> - GEM_BUG_ON(order < min_order);
>> -
>> - do {
>> - mutex_lock(&bman->lock);
>> - block = drm_buddy_alloc(mm, order);
>> - mutex_unlock(&bman->lock);
>> - if (!IS_ERR(block))
>> - break;
>> -
>> - if (order-- == min_order) {
>> - err = -ENOSPC;
>> - goto err_free_blocks;
>> - }
>> - } while (1);
>> -
>> - n_pages -= BIT(order);
>> -
>> - list_add_tail(&block->link, &bman_res->blocks);
>> -
>> - if (!n_pages)
>> - break;
>> - } while (1);
>> + mutex_lock(&bman->lock);
>> + err = drm_buddy_alloc(mm, (u64)place->fpfn << PAGE_SHIFT,
>> + (u64)place->lpfn << PAGE_SHIFT,
>
> place->lpfn will currently always be zero for i915, AFAIK. I assume here
> we want s/place->lpfn/lpfn/?
I replaced place->lpfn with lpfn as below
>> + err = drm_buddy_alloc(mm, (u64)place->fpfn << PAGE_SHIFT,
>> + (u64)lpfn << PAGE_SHIFT,
AFAIK, we need to change only at above location, hope this
fixes the firmware allocation issue.
>
> Also something in this series is preventing i915 from loading on
> discrete devices, according to CI. Hopefully that is just the lpfn
> issue...which might explain seeing -EINVAL here[1] when allocating some
> vram for the firmware.
>
> [1]
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fintel-gfx-ci.01.org%2Ftree%2Fdrm-tip%2FPatchwork_21904%2Fbat-dg1-6%2Fboot0.txt&data=04%7C01%7Carunpravin.paneerselvam%40amd.com%7C4e7c1345d6a649a1682608d9cf8ae82e%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637769017786517465%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=FsSHcnvbMhPhWaZ3tVLAswf04p5tBsbSYqKdYzpib88%3D&reserved=0
>
>
>> + (u64)n_pages << PAGE_SHIFT,
>> + min_page_size,
>> + &bman_res->blocks,
>> + bman_res->flags);
>> + mutex_unlock(&bman->lock);
>> + if (unlikely(err))
>> + goto err_free_blocks;
>>
>> *res = &bman_res->base;
>> return 0;
>> @@ -266,10 +258,17 @@ int i915_ttm_buddy_man_reserve(struct ttm_resource_manager *man,
>> {
>> struct i915_ttm_buddy_manager *bman = to_buddy_manager(man);
>> struct drm_buddy_mm *mm = &bman->mm;
>> + unsigned long flags = 0;
>> int ret;
>>
>> + flags |= DRM_BUDDY_RANGE_ALLOCATION;
>> +
>> mutex_lock(&bman->lock);
>> - ret = drm_buddy_alloc_range(mm, &bman->reserved, start, size);
>> + ret = drm_buddy_alloc(mm, start,
>> + start + size,
>> + size, mm->chunk_size,
>> + &bman->reserved,
>> + flags);
>> mutex_unlock(&bman->lock);
>>
>> return ret;
>> diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
>> index fa644b512c2e..5ba490875f66 100644
>> --- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
>> +++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.h
>> @@ -20,6 +20,7 @@ struct drm_buddy_mm;
>> *
>> * @base: struct ttm_resource base class we extend
>> * @blocks: the list of struct i915_buddy_block for this resource/allocation
>> + * @flags: DRM_BUDDY_*_ALLOCATION flags
>> * @mm: the struct i915_buddy_mm for this resource
>> *
>> * Extends the struct ttm_resource to manage an address space allocation with
>> @@ -28,6 +29,7 @@ struct drm_buddy_mm;
>> struct i915_ttm_buddy_resource {
>> struct ttm_resource base;
>> struct list_head blocks;
>> + unsigned long flags;
>> struct drm_buddy_mm *mm;
>> };
>>
>> diff --git a/include/drm/drm_buddy.h b/include/drm/drm_buddy.h
>> index 09d73328c268..4368acaad222 100644
>> --- a/include/drm/drm_buddy.h
>> +++ b/include/drm/drm_buddy.h
>> @@ -13,15 +13,22 @@
>>
>> #include <drm/drm_print.h>
>>
>> -#define range_overflows(start, size, max) ({ \
>> +#define check_range_overflow(start, end, size, max) ({ \
>> typeof(start) start__ = (start); \
>> + typeof(end) end__ = (end);\
>> typeof(size) size__ = (size); \
>> typeof(max) max__ = (max); \
>> (void)(&start__ == &size__); \
>> (void)(&start__ == &max__); \
>> - start__ >= max__ || size__ > max__ - start__; \
>> + (void)(&start__ == &end__); \
>> + (void)(&end__ == &size__); \
>> + (void)(&end__ == &max__); \
>> + start__ >= max__ || end__ > max__ || \
>> + size__ > end__ - start__; \
>> })
>>
>> +#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);
>> -
>> -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);
>>
>>
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