[PATCH 2/2] drm/amdgpu: use xarray for storing pasid in vm
Das, Nirmoy
nirmoy.das at amd.com
Wed Jun 23 13:11:32 UTC 2021
On 6/23/2021 2:50 PM, Christian König wrote:
>
>
> Am 23.06.21 um 14:25 schrieb Nirmoy Das:
>> Replace idr with xarray as we actually need hash functionality.
>> Cleanup code related to vm pasid by adding helper function.
>>
>> Signed-off-by: Nirmoy Das <nirmoy.das at amd.com>
>> ---
>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 134 +++++++++++--------------
>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h | 3 +-
>> 2 files changed, 60 insertions(+), 77 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> index be841d62a1d4..e047e56a4be2 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>> @@ -87,6 +87,39 @@ struct amdgpu_prt_cb {
>> struct dma_fence_cb cb;
>> };
>> +static int amdgpu_vm_set_pasid(struct amdgpu_device *adev,
>> + struct amdgpu_vm *vm,
>> + unsigned long pasid)
>
> Some kerneldoc please describing why we have that function.
Alright.
>
>> +{
>> + unsigned long flags;
>> + int r;
>> +
>> + if (pasid) {
>
> You should probably reorder the code so that the old pasid is first
> removed and then eventually the new one added.
>
>> + xa_lock_irqsave(&adev->vm_manager.pasids, flags);
>> + r = xa_err(__xa_store(&adev->vm_manager.pasids, pasid, vm,
>> + GFP_ATOMIC));
>> + xa_unlock_irqrestore(&adev->vm_manager.pasids, flags);
>
> As far as I can see this can just use xa_store() which also drops the
> need for GFP_ATOMIC here.
Do we need to have this irqsave/restore to keep passids safe for
amdgpu_vm_handle_fault() ?
xa_store() takes the spinlock without irq flags so I wanted to keep old
behavior.
>
>> + if (r < 0)
>> + return r;
>> + } else {
>> + unsigned long index;
>> + struct amdgpu_vm *res;
>> +
>> + xa_lock_irqsave(&adev->vm_manager.pasids, flags);
>> + xa_for_each(&adev->vm_manager.pasids, index, res) {
>> + if (res == vm) {
>> + __xa_erase(&adev->vm_manager.pasids, index);
>> + break;
>> + }
>> + }
>> + xa_unlock_irqrestore(&adev->vm_manager.pasids, flags);
>
> That is really ugly, why is that necessary?
Do you mean the lock around xa_for_each() ? I think I can just used lock
around __xa_erase() or just xa_erase() if just simple spinlock without
flags is enough.
Regards,
Nirmoy
>
> Christian
>
>> + }
>> +
>> + vm->pasid = pasid;
>> +
>> + return 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 +2973,9 @@ 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;
>> - }
>> + r = amdgpu_vm_set_pasid(adev, vm, pasid);
>> + if (r)
>> + goto error_free_root;
>> INIT_KFIFO(vm->faults);
>> @@ -3039,18 +3063,11 @@ int amdgpu_vm_make_compute(struct
>> amdgpu_device *adev, struct amdgpu_vm *vm,
>> if (r)
>> 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;
>> - }
>> + /* remove previous {pasid:vm} entry first */
>> + r = amdgpu_vm_set_pasid(adev, vm, 0);
>> + r = amdgpu_vm_set_pasid(adev, vm, pasid);
>> + if (r)
>> + goto unreserve_bo;
>> /* Check if PD needs to be reinitialized and do it before
>> * changing any other state, in case it fails.
>> @@ -3061,7 +3078,7 @@ int amdgpu_vm_make_compute(struct amdgpu_device
>> *adev, struct amdgpu_vm *vm,
>> to_amdgpu_bo_vm(vm->root.bo),
>> false);
>> if (r)
>> - goto free_idr;
>> + goto free_pasid_entry;
>> }
>> /* Update VM state */
>> @@ -3078,7 +3095,7 @@ int amdgpu_vm_make_compute(struct amdgpu_device
>> *adev, struct amdgpu_vm *vm,
>> r = amdgpu_bo_sync_wait(vm->root.bo,
>> AMDGPU_FENCE_OWNER_UNDEFINED, true);
>> if (r)
>> - goto free_idr;
>> + goto free_pasid_entry;
>> vm->update_funcs = &amdgpu_vm_cpu_funcs;
>> } else {
>> @@ -3088,31 +3105,14 @@ int amdgpu_vm_make_compute(struct
>> amdgpu_device *adev, struct amdgpu_vm *vm,
>> vm->last_update = NULL;
>> 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);
>> - vm->pasid = 0;
>> - }
>> -
>> /* 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;
>> +free_pasid_entry:
>> + amdgpu_vm_set_pasid(adev, vm, 0);
>> - 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;
>> @@ -3128,14 +3128,7 @@ 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_set_pasid(adev, vm, 0);
>> vm->is_compute_context = false;
>> }
>> @@ -3159,15 +3152,7 @@ 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_set_pasid(adev, vm, 0);
>> dma_fence_wait(vm->last_unlocked, false);
>> dma_fence_put(vm->last_unlocked);
>> @@ -3249,8 +3234,7 @@ void amdgpu_vm_manager_init(struct
>> amdgpu_device *adev)
>> adev->vm_manager.vm_update_mode = 0;
>> #endif
>> - idr_init(&adev->vm_manager.pasid_idr);
>> - spin_lock_init(&adev->vm_manager.pasid_lock);
>> + xa_init_flags(&adev->vm_manager.pasids, XA_FLAGS_LOCK_IRQ);
>> }
>> /**
>> @@ -3262,8 +3246,8 @@ void amdgpu_vm_manager_init(struct
>> amdgpu_device *adev)
>> */
>> void amdgpu_vm_manager_fini(struct amdgpu_device *adev)
>> {
>> - WARN_ON(!idr_is_empty(&adev->vm_manager.pasid_idr));
>> - idr_destroy(&adev->vm_manager.pasid_idr);
>> + WARN_ON(!xa_empty(&adev->vm_manager.pasids));
>> + xa_destroy(&adev->vm_manager.pasids);
>> amdgpu_vmid_mgr_fini(adev);
>> }
>> @@ -3332,13 +3316,13 @@ void amdgpu_vm_get_task_info(struct
>> amdgpu_device *adev, u32 pasid,
>> struct amdgpu_vm *vm;
>> unsigned long flags;
>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, flags);
>> + xa_lock_irqsave(&adev->vm_manager.pasids, flags);
>> - vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
>> + vm = xa_load(&adev->vm_manager.pasids, pasid);
>> if (vm)
>> *task_info = vm->task_info;
>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, flags);
>> + xa_unlock_irqrestore(&adev->vm_manager.pasids, flags);
>> }
>> /**
>> @@ -3380,15 +3364,15 @@ bool amdgpu_vm_handle_fault(struct
>> amdgpu_device *adev, u32 pasid,
>> struct amdgpu_vm *vm;
>> int r;
>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, irqflags);
>> - vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
>> + xa_lock_irqsave(&adev->vm_manager.pasids, irqflags);
>> + vm = xa_load(&adev->vm_manager.pasids, pasid);
>> if (vm) {
>> root = amdgpu_bo_ref(vm->root.bo);
>> is_compute_context = vm->is_compute_context;
>> } else {
>> root = NULL;
>> }
>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, irqflags);
>> + xa_unlock_irqrestore(&adev->vm_manager.pasids, irqflags);
>> if (!root)
>> return false;
>> @@ -3406,11 +3390,11 @@ bool amdgpu_vm_handle_fault(struct
>> amdgpu_device *adev, u32 pasid,
>> goto error_unref;
>> /* Double check that the VM still exists */
>> - spin_lock_irqsave(&adev->vm_manager.pasid_lock, irqflags);
>> - vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
>> + xa_lock_irqsave(&adev->vm_manager.pasids, irqflags);
>> + vm = xa_load(&adev->vm_manager.pasids, pasid);
>> if (vm && vm->root.bo != root)
>> vm = NULL;
>> - spin_unlock_irqrestore(&adev->vm_manager.pasid_lock, irqflags);
>> + xa_unlock_irqrestore(&adev->vm_manager.pasids, irqflags);
>> if (!vm)
>> goto error_unlock;
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>> index ddb85a85cbba..31c467764162 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
>> @@ -359,8 +359,7 @@ struct amdgpu_vm_manager {
>> /* PASID to VM mapping, will be used in interrupt context to
>> * look up VM of a page fault
>> */
>> - struct idr pasid_idr;
>> - spinlock_t pasid_lock;
>> + struct xarray pasids;
>> };
>> struct amdgpu_bo_va_mapping;
>
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