[Nouveau] [PATCH 2/2] nouveau: Do not add most bo's to the global bo list.

[Maarten Lankhorst]

Op 25-02-15 om 15:11 schreef Emil Velikov:
> On 24 February 2015 at 09:01, Maarten Lankhorst
> <maarten.lankhorst at ubuntu.com> wrote:
>> Only add wrapped bo's and bo's that have been exported through flink or dma-buf.
>> This avoids a lock in the common case, and decreases traversal needed for importing
>> a dma-buf or flink.
>>
>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at ubuntu.com>
>> ---
>>  nouveau/nouveau.c | 47 +++++++++++++++++++++++------------------------
>>  1 file changed, 23 insertions(+), 24 deletions(-)
>>
>> diff --git a/nouveau/nouveau.c b/nouveau/nouveau.c
>> index 1c723b9..d411523 100644
>> --- a/nouveau/nouveau.c
>> +++ b/nouveau/nouveau.c
>> @@ -349,8 +349,8 @@ nouveau_bo_del(struct nouveau_bo *bo)
>>         struct nouveau_bo_priv *nvbo = nouveau_bo(bo);
>>         struct drm_gem_close req = { bo->handle };
>>
>> -       pthread_mutex_lock(&nvdev->lock);
>> -       if (nvbo->name) {
>> +       if (nvbo->head.next) {
>> +               pthread_mutex_lock(&nvdev->lock);
>>                 if (atomic_read(&nvbo->refcnt) == 0) {
>>                         DRMLISTDEL(&nvbo->head);
>>                         /*
>> @@ -365,8 +365,6 @@ nouveau_bo_del(struct nouveau_bo *bo)
>>                 }
>>                 pthread_mutex_unlock(&nvdev->lock);
>>         } else {
>> -               DRMLISTDEL(&nvbo->head);
>> -               pthread_mutex_unlock(&nvdev->lock);
>>                 drmIoctl(bo->device->fd, DRM_IOCTL_GEM_CLOSE, &req);
>>         }
>>         if (bo->map)
>> @@ -379,7 +377,6 @@ nouveau_bo_new(struct nouveau_device *dev, uint32_t flags, uint32_t align,
>>                uint64_t size, union nouveau_bo_config *config,
>>                struct nouveau_bo **pbo)
>>  {
>> -       struct nouveau_device_priv *nvdev = nouveau_device(dev);
>>         struct nouveau_bo_priv *nvbo = calloc(1, sizeof(*nvbo));
>>         struct nouveau_bo *bo = &nvbo->base;
>>         int ret;
>> @@ -397,10 +394,6 @@ nouveau_bo_new(struct nouveau_device *dev, uint32_t flags, uint32_t align,
>>                 return ret;
>>         }
>>
>> -       pthread_mutex_lock(&nvdev->lock);
>> -       DRMLISTADD(&nvbo->head, &nvdev->bo_list);
>> -       pthread_mutex_unlock(&nvdev->lock);
>> -
>>         *pbo = bo;
>>         return 0;
>>  }
>> @@ -457,6 +450,18 @@ nouveau_bo_wrap_locked(struct nouveau_device *dev, uint32_t handle,
>>         return -ENOMEM;
>>  }
>>
>> +static void
>> +nouveau_bo_make_global(struct nouveau_bo_priv *nvbo)
>> +{
>> +       if (!nvbo->head.next) {
>> +               struct nouveau_device_priv *nvdev = nouveau_device(nvbo->base.device);
>> +               pthread_mutex_lock(&nvdev->lock);
>> +               if (!nvbo->head.next)
> Something looks a bit strange here. The list is modified under a lock,
> so there should be no need for the second if above. Did you have
> something else in mind ?
The unlocked if check could be removed, but checking is cheaper than locking. :P
I guess the bo_make_global call is not particularly sensitive, so removing's fine with me.

~Maarten