Am 10.09.2018 um 11:55 schrieb Deng, Emily:
-----Original Message-----
From: amd-gfx <amd-gfx-boun...@lists.freedesktop.org> On Behalf Of
Christian König
Sent: Monday, September 10, 2018 5:49 PM
To: Deng, Emily <emily.d...@amd.com>; amd-gfx@lists.freedesktop.org
Subject: Re: [PATCH v2] drm/amdgpu: Fix the dead lock issue.
Am 10.09.2018 um 11:47 schrieb Deng, Emily:
-----Original Message-----
From: Christian König <ckoenig.leichtzumer...@gmail.com>
Sent: Monday, September 10, 2018 5:41 PM
To: Deng, Emily <emily.d...@amd.com>; amd-gfx@lists.freedesktop.org
Subject: Re: [PATCH v2] drm/amdgpu: Fix the dead lock issue.
Am 10.09.2018 um 11:34 schrieb Emily Deng:
It will ramdomly have the dead lock issue when test TDR:
1. amdgpu_device_handle_vram_lost gets the lock shadow_list_lock 2.
amdgpu_bo_create locked the bo's resv lock 3.
amdgpu_bo_create_shadow is waiting for the shadow_list_lock 4.
amdgpu_device_recover_vram_from_shadow is waiting for the bo's resv
lock.
v2:
Make a local copy of the list
Signed-off-by: Emily Deng <emily.d...@amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 12 +++++++++++-
drivers/gpu/drm/amd/amdgpu/amdgpu_object.h | 1 +
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index acfc63e..2b9f597 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -3006,6 +3006,9 @@ static int
amdgpu_device_handle_vram_lost(struct amdgpu_device *adev)
long r = 1;
int i = 0;
long tmo;
+ struct list_head local_shadow_list;
+
+ INIT_LIST_HEAD(&local_shadow_list);
if (amdgpu_sriov_runtime(adev))
tmo = msecs_to_jiffies(8000);
@@ -3013,8 +3016,15 @@ static int
amdgpu_device_handle_vram_lost(struct amdgpu_device *adev)
tmo = msecs_to_jiffies(100);
DRM_INFO("recover vram bo from shadow start\n");
+
mutex_lock(&adev->shadow_list_lock);
list_for_each_entry_safe(bo, tmp, &adev->shadow_list,
shadow_list) {
+ amdgpu_bo_ref(bo);
+ list_add_tail(&bo->copy_shadow_list, &local_shadow_list);
+ }
Please don't add an extra copy_shadow_list field to amdgpu_bo.
If don't use an extra variable, the local shadow list will change
according the adev->shadow_list, both for adding or deleting, it is not we
want.
That is not correct, see amdgpu_bo_destroy:
if (!list_empty(&bo->shadow_list)) {
mutex_lock(&adev->shadow_list_lock);
list_del_init(&bo->shadow_list);
mutex_unlock(&adev->shadow_list_lock);
}
The BO is only removed from the list when it is destroyed, since we grabbed a
local reference it can't be destroyed. So we are safe here.
Sorry I am not meaning the delete, what about the adding.
That will still go to adev->shadow_list and not affect our local list in
any way.
We are not interested in any newly allocated shadow BOs, so that should
be unproblematic.
Regards,
Christian.
Regards,
Christian.
Instead just use bo->shadow list for this. When you hold a reference
to the BO it should not be removed from the shadow list.
Additional to that you can just use list_splice_init() to move the
whole shadow list to your local list.
Christian.
+ mutex_unlock(&adev->shadow_list_lock);
+
+ list_for_each_entry_safe(bo, tmp, &local_shadow_list,
+copy_shadow_list) {
next = NULL;
amdgpu_device_recover_vram_from_shadow(adev, ring, bo,
&next);
if (fence) {
@@ -3033,8 +3043,8 @@ static int
amdgpu_device_handle_vram_lost(struct
amdgpu_device *adev)
dma_fence_put(fence);
fence = next;
+ amdgpu_bo_unref(&bo);
}
- mutex_unlock(&adev->shadow_list_lock);
if (fence) {
r = dma_fence_wait_timeout(fence, false, tmo); diff --git
a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
index 907fdf4..cfee16c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
@@ -103,6 +103,7 @@ struct amdgpu_bo {
struct list_head mn_list;
struct list_head shadow_list;
};
+ struct list_head copy_shadow_list;
struct kgd_mem *kfd_bo;
};
_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
