[PATCH 03/11] drm/amdgpu: remove VM fault_credit handling

Zeng, Oak Oak.Zeng at amd.com
Fri Nov 30 21:07:11 UTC 2018


The credit was used to limit vm (retry) fault to be processed in each VM. If this is removed, it is possible that you get flooded interrupt storm.

Even though you claimed from the commit message that, printk_ratelimit is a better solution, I didn't see you implement it in this patch. Are you planning a future patch?

Thanks,
Oak

-----Original Message-----
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Christian König
Sent: Friday, November 30, 2018 7:36 AM
To: amd-gfx at lists.freedesktop.org
Subject: [PATCH 03/11] drm/amdgpu: remove VM fault_credit handling

printk_ratelimit() is much better suited to limit the number of reported VM faults.

Signed-off-by: Christian König <christian.koenig at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c  | 37 -------------------------  drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h  |  5 ----
 drivers/gpu/drm/amd/amdgpu/cik_ih.c     | 18 +-----------
 drivers/gpu/drm/amd/amdgpu/cz_ih.c      | 18 +-----------
 drivers/gpu/drm/amd/amdgpu/iceland_ih.c | 18 +-----------
 drivers/gpu/drm/amd/amdgpu/tonga_ih.c   | 18 +-----------
 drivers/gpu/drm/amd/amdgpu/vega10_ih.c  |  7 ++---
 7 files changed, 6 insertions(+), 115 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 2acb9838913e..a2f149da83f8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -3057,7 +3057,6 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm,
 	}
 
 	INIT_KFIFO(vm->faults);
-	vm->fault_credit = 16;
 
 	return 0;
 
@@ -3269,42 +3268,6 @@ void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
 		amdgpu_vmid_free_reserved(adev, vm, i);  }
 
-/**
- * amdgpu_vm_pasid_fault_credit - Check fault credit for given PASID
- *
- * @adev: amdgpu_device pointer
- * @pasid: PASID do identify the VM
- *
- * This function is expected to be called in interrupt context.
- *
- * Returns:
- * True if there was fault credit, false otherwise
- */
-bool amdgpu_vm_pasid_fault_credit(struct amdgpu_device *adev,
-				  unsigned int pasid)
-{
-	struct amdgpu_vm *vm;
-
-	spin_lock(&adev->vm_manager.pasid_lock);
-	vm = idr_find(&adev->vm_manager.pasid_idr, pasid);
-	if (!vm) {
-		/* VM not found, can't track fault credit */
-		spin_unlock(&adev->vm_manager.pasid_lock);
-		return true;
-	}
-
-	/* No lock needed. only accessed by IRQ handler */
-	if (!vm->fault_credit) {
-		/* Too many faults in this VM */
-		spin_unlock(&adev->vm_manager.pasid_lock);
-		return false;
-	}
-
-	vm->fault_credit--;
-	spin_unlock(&adev->vm_manager.pasid_lock);
-	return true;
-}
-
 /**
  * amdgpu_vm_manager_init - init the VM manager
  *
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index 2a8898d19c8b..e8dcfd59fc93 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -229,9 +229,6 @@ struct amdgpu_vm {
 	/* Up to 128 pending retry page faults */
 	DECLARE_KFIFO(faults, u64, 128);
 
-	/* Limit non-retry fault storms */
-	unsigned int		fault_credit;
-
 	/* Points to the KFD process VM info */
 	struct amdkfd_process_info *process_info;
 
@@ -299,8 +296,6 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm,  int amdgpu_vm_make_compute(struct amdgpu_device *adev, struct amdgpu_vm *vm, unsigned int pasid);  void amdgpu_vm_release_compute(struct amdgpu_device *adev, struct amdgpu_vm *vm);  void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm); -bool amdgpu_vm_pasid_fault_credit(struct amdgpu_device *adev,
-				  unsigned int pasid);
 void amdgpu_vm_get_pd_bo(struct amdgpu_vm *vm,
 			 struct list_head *validated,
 			 struct amdgpu_bo_list_entry *entry); diff --git a/drivers/gpu/drm/amd/amdgpu/cik_ih.c b/drivers/gpu/drm/amd/amdgpu/cik_ih.c
index b5775c6a857b..3e6c8c4067cb 100644
--- a/drivers/gpu/drm/amd/amdgpu/cik_ih.c
+++ b/drivers/gpu/drm/amd/amdgpu/cik_ih.c
@@ -237,23 +237,7 @@ static u32 cik_ih_get_wptr(struct amdgpu_device *adev)
  */
 static bool cik_ih_prescreen_iv(struct amdgpu_device *adev)  {
-	u32 ring_index = adev->irq.ih.rptr >> 2;
-	u16 pasid;
-
-	switch (le32_to_cpu(adev->irq.ih.ring[ring_index]) & 0xff) {
-	case 146:
-	case 147:
-		pasid = le32_to_cpu(adev->irq.ih.ring[ring_index + 2]) >> 16;
-		if (!pasid || amdgpu_vm_pasid_fault_credit(adev, pasid))
-			return true;
-		break;
-	default:
-		/* Not a VM fault */
-		return true;
-	}
-
-	adev->irq.ih.rptr += 16;
-	return false;
+	return true;
 }
 
  /**
diff --git a/drivers/gpu/drm/amd/amdgpu/cz_ih.c b/drivers/gpu/drm/amd/amdgpu/cz_ih.c
index df5ac4d85a00..447b3cbc47e5 100644
--- a/drivers/gpu/drm/amd/amdgpu/cz_ih.c
+++ b/drivers/gpu/drm/amd/amdgpu/cz_ih.c
@@ -216,23 +216,7 @@ static u32 cz_ih_get_wptr(struct amdgpu_device *adev)
  */
 static bool cz_ih_prescreen_iv(struct amdgpu_device *adev)  {
-	u32 ring_index = adev->irq.ih.rptr >> 2;
-	u16 pasid;
-
-	switch (le32_to_cpu(adev->irq.ih.ring[ring_index]) & 0xff) {
-	case 146:
-	case 147:
-		pasid = le32_to_cpu(adev->irq.ih.ring[ring_index + 2]) >> 16;
-		if (!pasid || amdgpu_vm_pasid_fault_credit(adev, pasid))
-			return true;
-		break;
-	default:
-		/* Not a VM fault */
-		return true;
-	}
-
-	adev->irq.ih.rptr += 16;
-	return false;
+	return true;
 }
 
 /**
diff --git a/drivers/gpu/drm/amd/amdgpu/iceland_ih.c b/drivers/gpu/drm/amd/amdgpu/iceland_ih.c
index cf0fc61aebe6..2b94a6d1550e 100644
--- a/drivers/gpu/drm/amd/amdgpu/iceland_ih.c
+++ b/drivers/gpu/drm/amd/amdgpu/iceland_ih.c
@@ -216,23 +216,7 @@ static u32 iceland_ih_get_wptr(struct amdgpu_device *adev)
  */
 static bool iceland_ih_prescreen_iv(struct amdgpu_device *adev)  {
-	u32 ring_index = adev->irq.ih.rptr >> 2;
-	u16 pasid;
-
-	switch (le32_to_cpu(adev->irq.ih.ring[ring_index]) & 0xff) {
-	case 146:
-	case 147:
-		pasid = le32_to_cpu(adev->irq.ih.ring[ring_index + 2]) >> 16;
-		if (!pasid || amdgpu_vm_pasid_fault_credit(adev, pasid))
-			return true;
-		break;
-	default:
-		/* Not a VM fault */
-		return true;
-	}
-
-	adev->irq.ih.rptr += 16;
-	return false;
+	return true;
 }
 
 /**
diff --git a/drivers/gpu/drm/amd/amdgpu/tonga_ih.c b/drivers/gpu/drm/amd/amdgpu/tonga_ih.c
index dcdbb4d72472..9d7b43da6acc 100644
--- a/drivers/gpu/drm/amd/amdgpu/tonga_ih.c
+++ b/drivers/gpu/drm/amd/amdgpu/tonga_ih.c
@@ -227,23 +227,7 @@ static u32 tonga_ih_get_wptr(struct amdgpu_device *adev)
  */
 static bool tonga_ih_prescreen_iv(struct amdgpu_device *adev)  {
-	u32 ring_index = adev->irq.ih.rptr >> 2;
-	u16 pasid;
-
-	switch (le32_to_cpu(adev->irq.ih.ring[ring_index]) & 0xff) {
-	case 146:
-	case 147:
-		pasid = le32_to_cpu(adev->irq.ih.ring[ring_index + 2]) >> 16;
-		if (!pasid || amdgpu_vm_pasid_fault_credit(adev, pasid))
-			return true;
-		break;
-	default:
-		/* Not a VM fault */
-		return true;
-	}
-
-	adev->irq.ih.rptr += 16;
-	return false;
+	return true;
 }
 
 /**
diff --git a/drivers/gpu/drm/amd/amdgpu/vega10_ih.c b/drivers/gpu/drm/amd/amdgpu/vega10_ih.c
index d84b687240d1..b49290bcf109 100644
--- a/drivers/gpu/drm/amd/amdgpu/vega10_ih.c
+++ b/drivers/gpu/drm/amd/amdgpu/vega10_ih.c
@@ -258,12 +258,9 @@ static bool vega10_ih_prescreen_iv(struct amdgpu_device *adev)
 	if (!pasid)
 		return true;
 
-	/* Not a retry fault, check fault credit */
-	if (!(dw5 & 0x80)) {
-		if (!amdgpu_vm_pasid_fault_credit(adev, pasid))
-			goto ignore_iv;
+	/* Not a retry fault */
+	if (!(dw5 & 0x80))
 		return true;
-	}
 
 	/* Track retry faults in per-VM fault FIFO. */
 	spin_lock(&adev->vm_manager.pasid_lock);
--
2.17.1

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