Am 03.03.20 um 15:34 schrieb He, Jacob:
[AMD Official Use Only - Internal Distribution Only]
/It would be better if we could do that asynchronously with a register
write on the ring.
/
Sorry, I don’t get your point. Could you please elaborate more?
You pass the ring from amdgpu_vm_flush() to the *_update_spm_vmid()
functions.
And then instead of using WREG32() you call amdgpu_ring_emit_wreg() to
make the write asynchronously on the ring buffer using a CP command.
This way we avoid a bunch of trouble when one process drops the VMID
reservation and another one grabs it.
Regards,
Christian.
Thanks
Jacob
*From: *Christian König <mailto:[email protected]>
*Sent: *Tuesday, March 3, 2020 10:16 PM
*To: *He, Jacob <mailto:[email protected]>;
[email protected] <mailto:[email protected]>
*Subject: *Re: [PATCH] drm/amdgpu: Update SPM_VMID with the job's vmid
when application reserves the vmid
Am 02.03.20 um 06:35 schrieb Jacob He:
> SPM access the video memory according to SPM_VMID. It should be updated
> with the job's vmid right before the job is scheduled. SPM_VMID is a
> global resource
>
> Change-Id: Id3881908960398f87e7c95026a54ff83ff826700
> Signed-off-by: Jacob He <[email protected]>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index c00696f3017e..c761d3a0b6e8 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -1080,8 +1080,12 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring,
struct amdgpu_job *job,
> struct dma_fence *fence = NULL;
> bool pasid_mapping_needed = false;
> unsigned patch_offset = 0;
> + bool update_spm_vmid_needed = (job->vm &&
(job->vm->reserved_vmid[vmhub] != NULL));
> int r;
>
> + if (update_spm_vmid_needed &&
adev->gfx.rlc.funcs->update_spm_vmid)
> + adev->gfx.rlc.funcs->update_spm_vmid(adev, job->vmid);
> +
It would be better if we could do that asynchronously with a register
write on the ring.
The alternative is that we block for the VM to be idle in
amdgpu_vm_ioctl() before unreserving the VMID.
In other words lock the reservation object of the root PD and call
amdgpu_vm_wait_idle() before calling amdgpu_vmid_free_reserved().
Regards,
Christian.
> if (amdgpu_vmid_had_gpu_reset(adev, id)) {
> gds_switch_needed = true;
> vm_flush_needed = true;
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