[PATCH 1/1] drm/amdgpu: add helper function for vm pasid
Das, Nirmoy
nirmoy.das at amd.com
Tue Jun 22 10:30:03 UTC 2021
On 6/22/2021 10:36 AM, Christian König wrote:
> Am 22.06.21 um 09:39 schrieb Das, Nirmoy:
>>
>> On 6/22/2021 9:03 AM, Christian König wrote:
>>>
>>>
>>> Am 22.06.21 um 08:57 schrieb Nirmoy Das:
>>>> Cleanup code related to vm pasid by adding helper functions.
>>>>
>>>> Signed-off-by: Nirmoy Das <nirmoy.das at amd.com>
>>>> ---
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 105
>>>> ++++++++++++-------------
>>>> 1 file changed, 50 insertions(+), 55 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>> index 63975bda8e76..6e476b173cbb 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>> @@ -87,6 +87,46 @@ struct amdgpu_prt_cb {
>>>> struct dma_fence_cb cb;
>>>> };
>>>>
>>>> +static int amdgpu_vm_pasid_alloc(struct amdgpu_device *adev,
>>>> + struct amdgpu_vm *vm,
>>>> + unsigned int pasid,
>>>> + unsigned int *vm_pasid)
>>>> +{
>>>> + unsigned long flags;
>>>> + int r;
>>>> +
>>>> + if (!pasid)
>>>> + return 0;
>>>> +
>>>> + spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>> + r = idr_alloc(&adev->vm_manager.pasid_idr, vm, pasid, pasid + 1,
>>>> + GFP_ATOMIC);
>>>> + spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>> + if (r < 0)
>>>> + return r;
>>>> + if (vm_pasid)
>>>> + *vm_pasid = pasid;
>>>> +
>>>
>>> Ok the more I read from this patch the less it makes sense.
>>>
>>> We don't allocate the passid here, we just set it up in the idr.
>>>
>>> What we could do is to replace the idr with an xarray, that would
>>> certainly make more sense than this here.
>>
>>
>> xarray looks great, with that we don't need pasid_lock either.
>
> You still need the lock to protect against VM destruction while
> looking things up, but you could switch to RCU for this instead.
xarray has xa_{lock|unloack}_irqsave() and adev->vm_manager.pasid_xa
will exist till devices's lifetime. So I am thinking something like:
amdgpu_vm_pasid_insert()
{
...
xa_lock_irqsave(adev->vm_manager.pasids, flags)
r = xa_store(&adev->vm_manager.pasids, pasid, vm, GFP_ATOMIC);
xa_unlock_irqsave(adev->vm_manager.pasids, flags)
}
amdgpu_vm_pasid_remove()
{
....
xa_lock_irqsave(adev->vm_manager.pasids, flags)
xa_erase(&adev->vm_manager.pasids, pasid);
xa_unlock_irqsave(adev->vm_manager.pasids, flags)
}
xa_{lock|unloack}_irqsave() can be use while looking up vm ptr for a pasid.
Shouldn't this be enough ?
Regards,
Nirmoy
>
> Christian.
>
>>
>>
>> Thanks
>>
>> Nirmoy
>>
>>
>>>
>>> Christian.
>>>
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static void amdgpu_vm_pasid_remove(struct amdgpu_device *adev,
>>>> + unsigned int pasid,
>>>> + unsigned int *vm_pasid)
>>>> +{
>>>> + unsigned long flags;
>>>> +
>>>> + if (!pasid)
>>>> + return;
>>>> +
>>>> + spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>> + idr_remove(&adev->vm_manager.pasid_idr, pasid);
>>>> + spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>> +
>>>> + if (vm_pasid)
>>>> + *vm_pasid = 0;
>>>> +}
>>>> +
>>>> /*
>>>> * vm eviction_lock can be taken in MMU notifiers. Make sure no
>>>> reclaim-FS
>>>> * happens while holding this lock anywhere to prevent deadlocks
>>>> when
>>>> @@ -2940,18 +2980,8 @@ int amdgpu_vm_init(struct amdgpu_device
>>>> *adev, struct amdgpu_vm *vm, u32 pasid)
>>>>
>>>> amdgpu_bo_unreserve(vm->root.bo);
>>>>
>>>> - if (pasid) {
>>>> - unsigned long flags;
>>>> -
>>>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>> - r = idr_alloc(&adev->vm_manager.pasid_idr, vm, pasid,
>>>> pasid + 1,
>>>> - GFP_ATOMIC);
>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>> - if (r < 0)
>>>> - goto error_free_root;
>>>> -
>>>> - vm->pasid = pasid;
>>>> - }
>>>> + if (amdgpu_vm_pasid_alloc(adev, vm, pasid, &vm->pasid))
>>>> + goto error_free_root;
>>>>
>>>> INIT_KFIFO(vm->faults);
>>>>
>>>> @@ -3038,19 +3068,11 @@ int amdgpu_vm_make_compute(struct
>>>> amdgpu_device *adev, struct amdgpu_vm *vm,
>>>> r = amdgpu_vm_check_clean_reserved(adev, vm);
>>>> if (r)
>>>> goto unreserve_bo;
>>>> + r = amdgpu_vm_pasid_alloc(adev, vm, pasid, NULL);
>>>> + if (r == -ENOSPC)
>>>> + goto unreserve_bo;
>>>>
>>>> - if (pasid) {
>>>> - unsigned long flags;
>>>> -
>>>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>> - r = idr_alloc(&adev->vm_manager.pasid_idr, vm, pasid,
>>>> pasid + 1,
>>>> - GFP_ATOMIC);
>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>> -
>>>> - if (r == -ENOSPC)
>>>> - goto unreserve_bo;
>>>> - r = 0;
>>>> - }
>>>> + r = 0;
>>>>
>>>> /* Check if PD needs to be reinitialized and do it before
>>>> * changing any other state, in case it fails.
>>>> @@ -3089,35 +3111,23 @@ int amdgpu_vm_make_compute(struct
>>>> amdgpu_device *adev, struct amdgpu_vm *vm,
>>>> vm->is_compute_context = true;
>>>>
>>>> if (vm->pasid) {
>>>> - unsigned long flags;
>>>> -
>>>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>> - idr_remove(&adev->vm_manager.pasid_idr, vm->pasid);
>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>> -
>>>> /* Free the original amdgpu allocated pasid
>>>> * Will be replaced with kfd allocated pasid
>>>> */
>>>> amdgpu_pasid_free(vm->pasid);
>>>> - vm->pasid = 0;
>>>> + amdgpu_vm_pasid_remove(adev, vm->pasid, &vm->pasid);
>>>> }
>>>>
>>>> /* Free the shadow bo for compute VM */
>>>> amdgpu_bo_unref(&to_amdgpu_bo_vm(vm->root.bo)->shadow);
>>>> -
>>>> if (pasid)
>>>> vm->pasid = pasid;
>>>>
>>>> goto unreserve_bo;
>>>>
>>>> free_idr:
>>>> - if (pasid) {
>>>> - unsigned long flags;
>>>> + amdgpu_vm_pasid_remove(adev, pasid, NULL);
>>>>
>>>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>> - idr_remove(&adev->vm_manager.pasid_idr, pasid);
>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>> - }
>>>> unreserve_bo:
>>>> amdgpu_bo_unreserve(vm->root.bo);
>>>> return r;
>>>> @@ -3133,14 +3143,7 @@ int amdgpu_vm_make_compute(struct
>>>> amdgpu_device *adev, struct amdgpu_vm *vm,
>>>> */
>>>> void amdgpu_vm_release_compute(struct amdgpu_device *adev, struct
>>>> amdgpu_vm *vm)
>>>> {
>>>> - if (vm->pasid) {
>>>> - unsigned long flags;
>>>> -
>>>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>> - idr_remove(&adev->vm_manager.pasid_idr, vm->pasid);
>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>> - }
>>>> - vm->pasid = 0;
>>>> + amdgpu_vm_pasid_remove(adev, vm->pasid, &vm->pasid);
>>>> vm->is_compute_context = false;
>>>> }
>>>>
>>>> @@ -3164,15 +3167,7 @@ void amdgpu_vm_fini(struct amdgpu_device
>>>> *adev, struct amdgpu_vm *vm)
>>>>
>>>> root = amdgpu_bo_ref(vm->root.bo);
>>>> amdgpu_bo_reserve(root, true);
>>>> - if (vm->pasid) {
>>>> - unsigned long flags;
>>>> -
>>>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>>>> - idr_remove(&adev->vm_manager.pasid_idr, vm->pasid);
>>>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>>>> - vm->pasid = 0;
>>>> - }
>>>> -
>>>> + amdgpu_vm_pasid_remove(adev, vm->pasid, &vm->pasid);
>>>> dma_fence_wait(vm->last_unlocked, false);
>>>> dma_fence_put(vm->last_unlocked);
>>>>
>>>> --
>>>> 2.32.0
>>>>
>>>
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>
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