[PATCH 1/2] drm/ttm: swap consecutive allocated cached pages

[Christian König]

Am 04.12.2017 um 12:51 schrieb Michel Dänzer:
> On 2017-12-04 12:42 PM, Christian König wrote:
>> When we detect consecutive allocation of pages swap them to avoid
>> accidentally freeing them as huge page.
>>
>> Signed-off-by: Christian König <christian.koenig at amd.com>
>> ---
>>   drivers/gpu/drm/ttm/ttm_page_alloc.c | 8 ++++++++
>>   1 file changed, 8 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c b/drivers/gpu/drm/ttm/ttm_page_alloc.c
>> index c82d94cbbabc..60401350a01a 100644
>> --- a/drivers/gpu/drm/ttm/ttm_page_alloc.c
>> +++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c
>> @@ -921,6 +921,14 @@ static int ttm_get_pages(struct page **pages, unsigned npages, int flags,
>>   				return -ENOMEM;
>>   			}
>>   
>> +			/* Swap the pages if we detect consecutive order */
>> +			if (i && pages[i - 1] == p - 1) {
>> +				struct page *tmp = p;
>> +
>> +				p = pages[i - 1];
>> +				pages[i - 1] = tmp;
>> +			}
>> +
> Should be (something like):
>
> 		if (i && pages[i - 1] == p - 1)
> 			swap(pages[i - 1], p);

Good point, updates patches send out a few seconds ago.

Please review,
Christian.