[PATCH 8/8] amdgpu: use sync file for shared semaphores (v2)
Christian König
deathsimple at vodafone.de
Tue Apr 4 07:40:57 UTC 2017
Am 04.04.2017 um 06:27 schrieb Dave Airlie:
> From: Dave Airlie <airlied at redhat.com>
>
> This creates a new interface for amdgpu with ioctls to
> create/destroy/import and export shared semaphores using
> sem object backed by the sync_file code. The semaphores
> are not installed as fd (except for export), but rather
> like other driver internal objects in an idr. The idr
> holds the initial reference on the sync file.
>
> The command submission interface is enhanced with two new
> chunks, one for semaphore waiting, one for semaphore signalling
> and just takes a list of handles for each.
>
> This is based on work originally done by David Zhou at AMD,
> with input from Christian Konig on what things should look like.
>
> NOTE: this interface addition needs a version bump to expose
> it to userspace.
>
> v1.1: keep file reference on import.
> v2: move to using syncobjs
>
> Signed-off-by: Dave Airlie <airlied at redhat.com>
Looks good to me in general, but one note below.
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 86 ++++++++++++++++++++++++++++++++-
> drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 2 +-
> include/uapi/drm/amdgpu_drm.h | 6 +++
> 3 files changed, 92 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> index 4671432..4dd210b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> @@ -27,6 +27,7 @@
> #include <linux/pagemap.h>
> #include <drm/drmP.h>
> #include <drm/amdgpu_drm.h>
> +#include <drm/drm_syncobj.h>
> #include "amdgpu.h"
> #include "amdgpu_trace.h"
>
> @@ -217,6 +218,8 @@ int amdgpu_cs_parser_init(struct amdgpu_cs_parser *p, void *data)
> break;
>
> case AMDGPU_CHUNK_ID_DEPENDENCIES:
> + case AMDGPU_CHUNK_ID_SEM_WAIT:
> + case AMDGPU_CHUNK_ID_SEM_SIGNAL:
> break;
>
> default:
> @@ -1009,6 +1012,44 @@ static int amdgpu_process_fence_dep(struct amdgpu_device *adev,
> return 0;
> }
>
> +static int amdgpu_sem_lookup_and_sync(struct amdgpu_device *adev,
> + struct drm_file *file_private,
> + struct amdgpu_sync *sync,
> + uint32_t handle)
> +{
> + int r;
> + struct dma_fence *old_fence;
> + r = drm_syncobj_swap_fences(file_private, handle, NULL, &old_fence);
What happens when we the CS fails later on? Would the semaphore then not
contain the fence any more?
Christian.
> + if (r)
> + return r;
> +
> + r = amdgpu_sync_fence(adev, sync, old_fence);
> + dma_fence_put(old_fence);
> +
> + return r;
> +}
> +
> +static int amdgpu_process_sem_wait_dep(struct amdgpu_device *adev,
> + struct amdgpu_cs_parser *p,
> + struct amdgpu_cs_chunk *chunk)
> +{
> + unsigned num_deps;
> + int i, r;
> + struct drm_amdgpu_cs_chunk_sem *deps;
> +
> + deps = (struct drm_amdgpu_cs_chunk_sem *)chunk->kdata;
> + num_deps = chunk->length_dw * 4 /
> + sizeof(struct drm_amdgpu_cs_chunk_sem);
> +
> + for (i = 0; i < num_deps; ++i) {
> + r = amdgpu_sem_lookup_and_sync(adev, p->filp, &p->job->sync,
> + deps[i].handle);
> + if (r)
> + return r;
> + }
> + return 0;
> +}
> +
> static int amdgpu_cs_dependencies(struct amdgpu_device *adev,
> struct amdgpu_cs_parser *p)
> {
> @@ -1023,12 +1064,55 @@ static int amdgpu_cs_dependencies(struct amdgpu_device *adev,
> r = amdgpu_process_fence_dep(adev, p, chunk);
> if (r)
> return r;
> + } else if (chunk->chunk_id == AMDGPU_CHUNK_ID_SEM_WAIT) {
> + r = amdgpu_process_sem_wait_dep(adev, p, chunk);
> + if (r)
> + return r;
> }
> }
>
> return 0;
> }
>
> +static int amdgpu_process_sem_signal_dep(struct amdgpu_cs_parser *p,
> + struct amdgpu_cs_chunk *chunk,
> + struct dma_fence *fence)
> +{
> + unsigned num_deps;
> + int i, r;
> + struct drm_amdgpu_cs_chunk_sem *deps;
> +
> + deps = (struct drm_amdgpu_cs_chunk_sem *)chunk->kdata;
> + num_deps = chunk->length_dw * 4 /
> + sizeof(struct drm_amdgpu_cs_chunk_sem);
> +
> + for (i = 0; i < num_deps; ++i) {
> + r = drm_syncobj_replace_fence(p->filp, deps[i].handle,
> + fence);
> + if (r)
> + return r;
> + }
> + return 0;
> +}
> +
> +static int amdgpu_cs_post_dependencies(struct amdgpu_cs_parser *p)
> +{
> + int i, r;
> +
> + for (i = 0; i < p->nchunks; ++i) {
> + struct amdgpu_cs_chunk *chunk;
> +
> + chunk = &p->chunks[i];
> +
> + if (chunk->chunk_id == AMDGPU_CHUNK_ID_SEM_SIGNAL) {
> + r = amdgpu_process_sem_signal_dep(p, chunk, p->fence);
> + if (r)
> + return r;
> + }
> + }
> + return 0;
> +}
> +
> static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
> union drm_amdgpu_cs *cs)
> {
> @@ -1056,7 +1140,7 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
> trace_amdgpu_cs_ioctl(job);
> amd_sched_entity_push_job(&job->base);
>
> - return 0;
> + return amdgpu_cs_post_dependencies(p);
> }
>
> int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> index b76cd69..e95951e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -683,7 +683,7 @@ static struct drm_driver kms_driver = {
> .driver_features =
> DRIVER_USE_AGP |
> DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED | DRIVER_GEM |
> - DRIVER_PRIME | DRIVER_RENDER | DRIVER_MODESET,
> + DRIVER_PRIME | DRIVER_RENDER | DRIVER_MODESET | DRIVER_SYNCOBJ,
> .load = amdgpu_driver_load_kms,
> .open = amdgpu_driver_open_kms,
> .preclose = amdgpu_driver_preclose_kms,
> diff --git a/include/uapi/drm/amdgpu_drm.h b/include/uapi/drm/amdgpu_drm.h
> index 5797283..647c520 100644
> --- a/include/uapi/drm/amdgpu_drm.h
> +++ b/include/uapi/drm/amdgpu_drm.h
> @@ -390,6 +390,8 @@ struct drm_amdgpu_gem_va {
> #define AMDGPU_CHUNK_ID_IB 0x01
> #define AMDGPU_CHUNK_ID_FENCE 0x02
> #define AMDGPU_CHUNK_ID_DEPENDENCIES 0x03
> +#define AMDGPU_CHUNK_ID_SEM_WAIT 0x04
> +#define AMDGPU_CHUNK_ID_SEM_SIGNAL 0x05
>
> struct drm_amdgpu_cs_chunk {
> __u32 chunk_id;
> @@ -454,6 +456,10 @@ struct drm_amdgpu_cs_chunk_fence {
> __u32 offset;
> };
>
> +struct drm_amdgpu_cs_chunk_sem {
> + __u32 handle;
> +};
> +
> struct drm_amdgpu_cs_chunk_data {
> union {
> struct drm_amdgpu_cs_chunk_ib ib_data;
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