On Fri, Sep 13, 2019 at 8:44 AM Steven Price steven.price@arm.com wrote:
On 13/09/2019 12:17, Boris Brezillon wrote:
The READ/WRITE flags are particularly useful if we want to avoid serialization of jobs that read from the same BO but never write to it. The NO_IMPLICIT_FENCE might be useful when the user knows the BO is shared but jobs are using different portions of the buffer.
Signed-off-by: Boris Brezillon boris.brezillon@collabora.com
Good feature - we could do with an (easy) way of the user driver detecting this - so it might be worth bumping the driver version for this?
Some more comments below.
drivers/gpu/drm/panfrost/panfrost_drv.c | 72 +++++++++-- drivers/gpu/drm/panfrost/panfrost_job.c | 164 +++++++++++++++++++----- drivers/gpu/drm/panfrost/panfrost_job.h | 11 +- include/uapi/drm/panfrost_drm.h | 41 ++++++ 4 files changed, 247 insertions(+), 41 deletions(-)
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c index d74442d71048..08082fd557c3 100644 --- a/drivers/gpu/drm/panfrost/panfrost_drv.c +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c @@ -119,20 +119,76 @@ panfrost_lookup_bos(struct drm_device *dev, struct drm_panfrost_submit *args, struct panfrost_job *job) {
job->bo_count = args->bo_handle_count;
struct drm_panfrost_submit_bo *bo_descs = NULL;u32 *handles = NULL;u32 i, bo_count;int ret = 0;
if (!job->bo_count)
bo_count = args->bo_desc_count ?args->bo_desc_count : args->bo_handle_count;if (!bo_count) return 0;
job->implicit_fences = kvmalloc_array(job->bo_count,sizeof(struct dma_fence *),
job->bos = kvmalloc_array(bo_count, sizeof(*job->bos), GFP_KERNEL | __GFP_ZERO);
if (!job->implicit_fences)
if (!job->bos) return -ENOMEM;
return drm_gem_objects_lookup(file_priv,(void __user *)(uintptr_t)args->bo_handles,job->bo_count, &job->bos);
job->bo_count = bo_count;bo_descs = kvmalloc_array(bo_count, sizeof(*bo_descs),GFP_KERNEL | __GFP_ZERO);if (!bo_descs) {ret = -ENOMEM;goto out;This can be just "return -ENOMEM" - both handles and bo_descs will be NULL.
}if (!args->bo_desc_count) {handles = kvmalloc_array(bo_count, sizeof(*handles),GFP_KERNEL);if (!handles) {ret =-ENOMEM;goto out;}if (copy_from_user(handles,(void __user *)(uintptr_t)args->bo_handles,job->bo_count * sizeof(*handles))) {ret = -EFAULT;goto out;}for (i = 0; i < job->bo_count; i++) {bo_descs[i].handle = handles[i];bo_descs[i].flags = PANFROST_SUBMIT_BO_WRITE |PANFROST_SUBMIT_BO_READ;You can use PANFROST_SUBMIT_BO_RW here.
}} else if (copy_from_user(bo_descs,(void __user *)(uintptr_t)args->bo_descs,job->bo_count * sizeof(*bo_descs))) {ret = -EFAULT;goto out;}for (i = 0; i < job->bo_count; i++) {if ((bo_descs[i].flags & ~PANFROST_SUBMIT_BO_VALID_FLAGS) ||!(bo_descs[i].flags & PANFROST_SUBMIT_BO_RW)) {ret = -EINVAL;goto out;}job->bos[i].flags = bo_descs[i].flags;job->bos[i].obj = drm_gem_object_lookup(file_priv,bo_descs[i].handle);if (!job->bos[i].obj) {ret = -ENOENT;goto out;}}+out:
kvfree(handles);kvfree(bo_descs);return ret;}
/** diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c index 05c85f45a0de..e4b74fde9339 100644 --- a/drivers/gpu/drm/panfrost/panfrost_job.c +++ b/drivers/gpu/drm/panfrost/panfrost_job.c @@ -193,24 +193,116 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js) pm_runtime_put_autosuspend(pfdev->dev); }
-static void panfrost_acquire_object_fences(struct drm_gem_object **bos,
int bo_count,struct dma_fence **implicit_fences)+static int panfrost_acquire_object_fences(struct panfrost_job *job) {
int i;
int i, ret;
for (i = 0; i < bo_count; i++)implicit_fences[i] = dma_resv_get_excl_rcu(bos[i]->resv);
for (i = 0; i < job->bo_count; i++) {struct panfrost_job_bo_desc *bo = &job->bos[i];struct dma_resv *robj = bo->obj->resv;if (!(job->bos[i].flags & PANFROST_SUBMIT_BO_WRITE)) {ret = dma_resv_reserve_shared(robj, 1);if (ret)return ret;}if (bo->flags & PANFROST_SUBMIT_BO_NO_IMPLICIT_FENCE)continue;if (bo->flags & PANFROST_SUBMIT_BO_WRITE) {ret = dma_resv_get_fences_rcu(robj, &bo->excl,&bo->shared_count,&bo->shared);if (ret)return ret;} else {bo->excl = dma_resv_get_excl_rcu(robj);}The implementation of NO_IMPLICIT_FENCE seems a bit strange to me: READ | NO_IMPLICIT_FENCE still reserves space for a shared fence. I don't understand why.
}return 0;}
-static void panfrost_attach_object_fences(struct drm_gem_object **bos,
int bo_count,struct dma_fence *fence)+static void panfrost_attach_object_fences(struct panfrost_job *job) { int i;
for (i = 0; i < bo_count; i++)dma_resv_add_excl_fence(bos[i]->resv, fence);
for (i = 0; i < job->bo_count; i++) {struct drm_gem_object *obj = job->bos[i].obj;if (job->bos[i].flags & PANFROST_SUBMIT_BO_WRITE)dma_resv_add_excl_fence(obj->resv,job->render_done_fence);elsedma_resv_add_shared_fence(obj->resv,job->render_done_fence);}+}
+static int panfrost_job_lock_bos(struct panfrost_job *job,
struct ww_acquire_ctx *acquire_ctx)+{
int contended = -1;int i, ret;ww_acquire_init(acquire_ctx, &reservation_ww_class);+retry:
if (contended != -1) {struct drm_gem_object *obj = job->bos[contended].obj;ret = ww_mutex_lock_slow_interruptible(&obj->resv->lock,acquire_ctx);dma_resv_lock_slot_interruptible()?
if (ret) {ww_acquire_done(acquire_ctx);return ret;}}for (i = 0; i < job->bo_count; i++) {if (i == contended)continue;ret = ww_mutex_lock_interruptible(&job->bos[i].obj->resv->lock,acquire_ctx);dma_resv_lock_interruptible()?
if (ret) {int j;for (j = 0; j < i; j++)ww_mutex_unlock(&job->bos[j].obj->resv->lock);if (contended != -1 && contended >= i) {struct drm_gem_object *contended_obj;contended_obj = job->bos[contended].obj;ww_mutex_unlock(&contended_obj->resv->lock);}if (ret == -EDEADLK) {contended = i;goto retry;}ww_acquire_done(acquire_ctx);return ret;}}ww_acquire_done(acquire_ctx);return 0;+}
This looks like a copy of drm_gem_lock_reservations(). The only reason for it as far as I can see is because we now have an array of struct panfrost_job_bo_desc rather than a direct array of struct drm_gem_object. I'm not sure having everything neatly in one structure is worth this cost?
I'm not thrilled about this either. If not a separate array, we could change the common code to work on a common struct instead.
To put it another way, this is all copy-n-paste from elsewhere that I don't really understand and want to maintain in the driver.
Rob