[PATCH 2/2] drm/ttm: optimize ttm_mem_evict_first v4

[Christian König]

Am 14.11.2017 um 03:40 schrieb Chunming Zhou:
>
>
> On 2017年11月13日 17:54, Christian König wrote:
>> Deleted BOs with the same reservation object can be reaped even if they
>> can't be reserved.
>>
>> v2: rebase and we still need to remove/add the BO from/to the LRU.
>> v3: fix remove/add one more time, cleanup the logic a bit
>> v4: we should still check if the eviction is valuable
>>
>> Signed-off-by: Christian König <christian.koenig at amd.com>
>> ---
>>   drivers/gpu/drm/ttm/ttm_bo.c | 54 
>> +++++++++++++++++++++++++++-----------------
>>   1 file changed, 33 insertions(+), 21 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
>> index 691646c0f8d3..7b1525d39ea8 100644
>> --- a/drivers/gpu/drm/ttm/ttm_bo.c
>> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
>> @@ -738,47 +738,57 @@ bool ttm_bo_eviction_valuable(struct 
>> ttm_buffer_object *bo,
>>   EXPORT_SYMBOL(ttm_bo_eviction_valuable);
>>     static int ttm_mem_evict_first(struct ttm_bo_device *bdev,
>> -                uint32_t mem_type,
>> -                const struct ttm_place *place,
>> -                bool interruptible,
>> -                bool no_wait_gpu)
>> +                   struct reservation_object *resv,
>> +                   uint32_t mem_type,
>> +                   const struct ttm_place *place,
>> +                   bool interruptible,
>> +                   bool no_wait_gpu)
>>   {
>>       struct ttm_bo_global *glob = bdev->glob;
>>       struct ttm_mem_type_manager *man = &bdev->man[mem_type];
>> -    struct ttm_buffer_object *bo;
>> -    int ret = -EBUSY;
>> +    struct ttm_buffer_object *bo = NULL;
>> +    bool locked = false;
>>       unsigned i;
>> +    int ret;
>>         spin_lock(&glob->lru_lock);
>>       for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
>>           list_for_each_entry(bo, &man->lru[i], lru) {
>> -            ret = reservation_object_trylock(bo->resv) ? 0 : -EBUSY;
>> -            if (ret)
>> -                continue;
>> +            if (bo->resv == resv) {
>> +                if (list_empty(&bo->ddestroy))
>> +                    continue;
> Do you have further patches for enabling eviction and swapout for 
> allocation?

Yeah, going to work on this.

Basically we need to add a context here so that TTM knows what to do. I 
had patches for this already done, but never pushed them because time 
constrains.

But that will probably a few weeks before I have that ready.

Regards,
Christian.

>
> Regards,
> David Zhou
>> +
>> +            } else {
>> +                locked = reservation_object_trylock(bo->resv);
>> +                if (!locked)
>> +                    continue;
>> +            }
>>                 if (place && !bdev->driver->eviction_valuable(bo,
>>                                         place)) {
>> -                reservation_object_unlock(bo->resv);
>> -                ret = -EBUSY;
>> +                if (locked)
>> +                    reservation_object_unlock(bo->resv);
>>                   continue;
>>               }
>> -
>>               break;
>>           }
>>   -        if (!ret)
>> +        if (&bo->lru != &man->lru[i])
>>               break;
>> +        else
>> +            bo = NULL;
>>       }
>>   -    if (ret) {
>> +    if (!bo) {
>>           spin_unlock(&glob->lru_lock);
>> -        return ret;
>> +        return -EBUSY;
>>       }
>>         kref_get(&bo->list_kref);
>>         if (!list_empty(&bo->ddestroy)) {
>> -        ret = ttm_bo_cleanup_refs(bo, interruptible, no_wait_gpu, 
>> true);
>> +        ret = ttm_bo_cleanup_refs(bo, interruptible, no_wait_gpu,
>> +                      locked);
>>           kref_put(&bo->list_kref, ttm_bo_release_list);
>>           return ret;
>>       }
>> @@ -786,10 +796,11 @@ static int ttm_mem_evict_first(struct 
>> ttm_bo_device *bdev,
>>       ttm_bo_del_from_lru(bo);
>>       spin_unlock(&glob->lru_lock);
>>   -    BUG_ON(ret != 0);
>> -
>>       ret = ttm_bo_evict(bo, interruptible, no_wait_gpu);
>> -    ttm_bo_unreserve(bo);
>> +    if (locked)
>> +        ttm_bo_unreserve(bo);
>> +    else
>> +        ttm_bo_add_to_lru(bo);
>>         kref_put(&bo->list_kref, ttm_bo_release_list);
>>       return ret;
>> @@ -853,7 +864,7 @@ static int ttm_bo_mem_force_space(struct 
>> ttm_buffer_object *bo,
>>               return ret;
>>           if (mem->mm_node)
>>               break;
>> -        ret = ttm_mem_evict_first(bdev, mem_type, place,
>> +        ret = ttm_mem_evict_first(bdev, bo->resv, mem_type, place,
>>                         interruptible, no_wait_gpu);
>>           if (unlikely(ret != 0))
>>               return ret;
>> @@ -1356,7 +1367,8 @@ static int ttm_bo_force_list_clean(struct 
>> ttm_bo_device *bdev,
>>       for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
>>           while (!list_empty(&man->lru[i])) {
>>               spin_unlock(&glob->lru_lock);
>> -            ret = ttm_mem_evict_first(bdev, mem_type, NULL, false, 
>> false);
>> +            ret = ttm_mem_evict_first(bdev, NULL, mem_type, NULL,
>> +                          false, false);
>>               if (ret)
>>                   return ret;
>>               spin_lock(&glob->lru_lock);
>