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Do you miss a file which adds spm_updated to vm structure?
________________________________
From: Liu, Monk <[email protected]>
Sent: Monday, April 20, 2020 3:32 PM
To: He, Jacob <[email protected]>; Koenig, Christian <[email protected]>
Cc: [email protected] <[email protected]>
Subject: why we need to do infinite RLC_SPM register setting during VM flush


Hi Jaco & Christian



As titled , check below patch:



commit 10790a09ea584cc832353a5c2a481012e5e31a13

Author: Jacob He <[email protected]>

Date:   Fri Feb 28 20:24:41 2020 +0800



    drm/amdgpu: Update SPM_VMID with the job's vmid when application reserves 
the vmid



    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]>

    Reviewed-by: Christian König <[email protected]>



diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

index 6e6fc8c..ba2236a 100644

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

@@ -1056,8 +1056,12 @@ 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);

+

        if (amdgpu_vmid_had_gpu_reset(adev, id)) {

                gds_switch_needed = true;

                vm_flush_needed = true;



this update_spm_vmid() looks an completely overkill to me, we only need to do 
it once for its VM …



in SRIOV the register reading/writing for update_spm_vmid() is now carried by 
KIQ thus there is too much burden on KIQ for such unnecessary jobs …



I want to change it to only do it once per VM, like:



diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

index 6e6fc8c..ba2236a 100644

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c

@@ -1056,8 +1056,12 @@ 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 &&  
!vm->spm_updated) {

+               adev->gfx.rlc.funcs->update_spm_vmid(adev, job->vmid);

+               vm->spm_updated = true;

+       }



        if (amdgpu_vmid_had_gpu_reset(adev, id)) {

                gds_switch_needed = true;

                vm_flush_needed = true;



what do you think ?



P.S.: the best way is to let GFX ring itself to do the update_spm_vmid() 
instead of let CPU doing it, e.g.: we put more PM4 command in VM-FLUSH packets 
….

But I prefer the simple way first like I demonstrated above

_____________________________________

Monk Liu|GPU Virtualization Team |AMD

[sig-cloud-gpu]


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