[Mesa-dev] [PATCH 3/8] i965/bufmgr: Drop the BO_ALLOC_BUSY flag

[Lionel Landwerlin]

On 14/06/18 14:01, Lionel Landwerlin wrote:
> On 13/06/18 21:26, Jason Ekstrand wrote:
>> ---
>>   src/mesa/drivers/dri/i965/brw_bufmgr.c | 46 ++++++--------------------
>>   src/mesa/drivers/dri/i965/brw_bufmgr.h |  1 -
>>   2 files changed, 10 insertions(+), 37 deletions(-)
>>
>> diff --git a/src/mesa/drivers/dri/i965/brw_bufmgr.c 
>> b/src/mesa/drivers/dri/i965/brw_bufmgr.c
>> index 58bb559fdee..e9d3daa5985 100644
>> --- a/src/mesa/drivers/dri/i965/brw_bufmgr.c
>> +++ b/src/mesa/drivers/dri/i965/brw_bufmgr.c
>> @@ -448,11 +448,6 @@ int
>>   brw_bo_busy(struct brw_bo *bo)
>>   {
>>      struct brw_bufmgr *bufmgr = bo->bufmgr;
>
> I don't really understand this hunk.
> It seems related to this patch and undoes what you added in patch 1.

I meant "unrelated".

>
>> -
>> -   /* If we know it's idle, don't bother with the kernel round trip */
>> -   if (bo->idle && !bo->external)
>> -      return false;
>> -
>>      struct drm_i915_gem_busy busy = { .handle = bo->gem_handle };
>>        int ret = drmIoctl(bufmgr->fd, DRM_IOCTL_I915_GEM_BUSY, &busy);
>> @@ -506,20 +501,11 @@ bo_alloc_internal(struct brw_bufmgr *bufmgr,
>>      struct bo_cache_bucket *bucket;
>>      bool alloc_from_cache;
>>      uint64_t bo_size;
>> -   bool busy = false;
>>      bool zeroed = false;
>>   -   if (flags & BO_ALLOC_BUSY)
>> -      busy = true;
>> -
>>      if (flags & BO_ALLOC_ZEROED)
>>         zeroed = true;
>>   -   /* BUSY does doesn't really jive with ZEROED as we have to wait 
>> for it to
>> -    * be idle before we can memset.  Just disallow that combination.
>> -    */
>> -   assert(!(busy && zeroed));
>> -
>>      /* Round the allocated size up to a power of two number of 
>> pages. */
>>      bucket = bucket_for_size(bufmgr, size);
>>   @@ -539,29 +525,17 @@ bo_alloc_internal(struct brw_bufmgr *bufmgr,
>>   retry:
>>      alloc_from_cache = false;
>>      if (bucket != NULL && !list_empty(&bucket->head)) {
>> -      if (busy && !zeroed) {
>> -         /* Allocate new render-target BOs from the tail (MRU)
>> -          * of the list, as it will likely be hot in the GPU
>> -          * cache and in the aperture for us.  If the caller
>> -          * asked us to zero the buffer, we don't want this
>> -          * because we are going to mmap it.
>> -          */
>> -         bo = LIST_ENTRY(struct brw_bo, bucket->head.prev, head);
>> -         list_del(&bo->head);
>> +      /* For non-render-target BOs (where we're probably
>> +       * going to map it first thing in order to fill it
>> +       * with data), check if the last BO in the cache is
>> +       * unbusy, and only reuse in that case. Otherwise,
>> +       * allocating a new buffer is probably faster than
>> +       * waiting for the GPU to finish.
>> +       */
>> +      bo = LIST_ENTRY(struct brw_bo, bucket->head.next, head);
>> +      if (!brw_bo_busy(bo)) {
>>            alloc_from_cache = true;
>> -      } else {
>> -         /* For non-render-target BOs (where we're probably
>> -          * going to map it first thing in order to fill it
>> -          * with data), check if the last BO in the cache is
>> -          * unbusy, and only reuse in that case. Otherwise,
>> -          * allocating a new buffer is probably faster than
>> -          * waiting for the GPU to finish.
>> -          */
>> -         bo = LIST_ENTRY(struct brw_bo, bucket->head.next, head);
>> -         if (!brw_bo_busy(bo)) {
>> -            alloc_from_cache = true;
>> -            list_del(&bo->head);
>> -         }
>> +         list_del(&bo->head);
>>         }
>>           if (alloc_from_cache) {
>> diff --git a/src/mesa/drivers/dri/i965/brw_bufmgr.h 
>> b/src/mesa/drivers/dri/i965/brw_bufmgr.h
>> index 32fc7a553c9..d3b3aadc0db 100644
>> --- a/src/mesa/drivers/dri/i965/brw_bufmgr.h
>> +++ b/src/mesa/drivers/dri/i965/brw_bufmgr.h
>> @@ -195,7 +195,6 @@ struct brw_bo {
>>      bool cache_coherent;
>>   };
>>   -#define BO_ALLOC_BUSY       (1<<0)
>>   #define BO_ALLOC_ZEROED     (1<<1)
>>     /**
>
>
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