[Intel-gfx] [PATCH] drm/i915: round_up the size to the alignment value

[Arunpravin]

On 15/03/22 4:56 pm, Matthew Auld wrote:
> On Mon, 14 Mar 2022 at 19:32, Arunpravin
> <Arunpravin.PaneerSelvam at amd.com> wrote:
>>
>> handle instances when size is not aligned with the min_page_size.
>> Unigine Heaven has allocation requests for example required pages
>> are 161 and alignment request is 128. To allocate the left over
>> 33 pages, continues the iteration to find the order value which
>> is 5 and 0 and when it compares with min_order = 7, triggers the
>> BUG_ON((order < min_order). To avoid this problem, round_up the
>> size to the alignment and enable the is_contiguous variable and
>> the block trimmed to the original size.
>>
>> Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam at amd.com>
>> ---
>>  drivers/gpu/drm/i915/i915_ttm_buddy_manager.c | 13 +++++++++++--
>>  1 file changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
>> index 129f668f21ff..318aa731de5b 100644
>> --- a/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
>> +++ b/drivers/gpu/drm/i915/i915_ttm_buddy_manager.c
>> @@ -40,6 +40,7 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
>>         struct i915_ttm_buddy_resource *bman_res;
>>         struct drm_buddy *mm = &bman->mm;
>>         unsigned long n_pages, lpfn;
>> +       bool is_contiguous = 0;
>>         u64 min_page_size;
>>         u64 size;
>>         int err;
>> @@ -48,6 +49,9 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
>>         if (!lpfn)
>>                 lpfn = man->size;
>>
>> +       if (place->flags & TTM_PL_FLAG_CONTIGUOUS)
>> +               is_contiguous = 1;
>> +
>>         bman_res = kzalloc(sizeof(*bman_res), GFP_KERNEL);
>>         if (!bman_res)
>>                 return -ENOMEM;
>> @@ -71,7 +75,12 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
>>
>>         GEM_BUG_ON(min_page_size < mm->chunk_size);
>>
>> -       if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
>> +       if (!is_contiguous && !IS_ALIGNED(size, min_page_size)) {
>> +               size = round_up(size, min_page_size);
>> +               is_contiguous = 1;
>> +       }
>> +
>> +       if (is_contiguous) {
> 
> This looks like it will also do roundup_power_of_two()? I assume we
> instead just want to feed the list_last_entry() block for trimming?
> 
> Anway, we should be able to just make this:
> 
> if (WARN_ON(!IS_ALIGNED(size, min_page_size))
>     return -EINVAL;
> 
> That's at least the currently expected behaviour in i915, just that we
> were previously not verifying it here.

ok sure, then I make changes in amdgpu
> 
>>                 unsigned long pages;
>>
>>                 size = roundup_pow_of_two(size);
>> @@ -106,7 +115,7 @@ static int i915_ttm_buddy_man_alloc(struct ttm_resource_manager *man,
>>         if (unlikely(err))
>>                 goto err_free_blocks;
>>
>> -       if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
>> +       if (is_contiguous) {
>>                 u64 original_size = (u64)bman_res->base.num_pages << PAGE_SHIFT;
>>
>>                 mutex_lock(&bman->lock);
>>
>> base-commit: b37605de46fef48555bf0cf463cccf355c51fac0
>> --
>> 2.25.1
>>