Re: [Freedreno] [PATCH 06/13] drm/msm: Use kzalloc for submit struct allocation

[Sharat Masetty <smasetty@codeaurora.org>]

On 10/1/2018 11:43 PM, Jordan Crouse wrote:
> On Mon, Oct 01, 2018 at 06:01:38PM +0530, Sharat Masetty wrote:
>> This patch changes to kzalloc and avoids setting individual submit
>> struct fields to zero manually.
> 
> I don't think this one is worth it.  There are so many members in submit and so
> few that get reset to 0 - I don't think the extra cycles are worth it in this
> fast path.
The patch "drm/msm: Use the DRM common Scheduler" adds a few more fields 
to the bo struct, If not kzalloc, then I will have to run a loop or 
memset the bos area to 0 at least.
> 
>> Signed-off-by: Sharat Masetty <smasetty@codeaurora.org>
>> ---
>>   drivers/gpu/drm/msm/msm_gem_submit.c | 7 +------
>>   1 file changed, 1 insertion(+), 6 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
>> index a7c8cbc..7931c2a 100644
>> --- a/drivers/gpu/drm/msm/msm_gem_submit.c
>> +++ b/drivers/gpu/drm/msm/msm_gem_submit.c
>> @@ -41,24 +41,19 @@ static struct msm_gem_submit *submit_create(struct drm_device *dev,
>>   	if (sz > SIZE_MAX)
>>   		return NULL;
>>   
>> -	submit = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);
>> +	submit = kzalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);
>>   	if (!submit)
>>   		return NULL;
>>   
>>   	submit->dev = dev;
>>   	submit->gpu = gpu;
>>   	submit->ctx = ctx;
>> -	submit->hw_fence = NULL;
>>   	submit->out_fence_id = -1;
>>   	submit->pid = get_pid(task_pid(current));
>>   	submit->cmd = (void *)&submit->bos[nr_bos];
>>   	submit->queue = queue;
>>   	submit->ring = gpu->rb[queue->prio];
>>   
>> -	/* initially, until copy_from_user() and bo lookup succeeds: */
>> -	submit->nr_bos = 0;
>> -	submit->nr_cmds = 0;
>> -
>>   	INIT_LIST_HEAD(&submit->node);
>>   	INIT_LIST_HEAD(&submit->bo_list);
>>   	ww_acquire_init(&submit->ticket, &reservation_ww_class);
>> -- 
>> 1.9.1
>>
> 

-- 
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