* [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper
@ 2018-08-31 13:10 Christian König
[not found] ` <20180831131019.2486-1-christian.koenig-5C7GfCeVMHo@public.gmane.org>
0 siblings, 1 reply; 14+ messages in thread
From: Christian König @ 2018-08-31 13:10 UTC (permalink / raw)
To: amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW; +Cc: michel.daenzer-5C7GfCeVMHo
Staring at the function for six hours, just to essentially move one line
of code.
Signed-off-by: Christian König <christian.koenig@amd.com>
---
drivers/gpu/drm/ttm/ttm_bo.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 35d53d81f486..138c98902033 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -250,15 +250,18 @@ EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
static void ttm_bo_bulk_move_helper(struct ttm_lru_bulk_move_pos *pos,
struct list_head *lru, bool is_swap)
{
+ struct list_head *list;
LIST_HEAD(entries);
LIST_HEAD(before);
- struct list_head *list1, *list2;
- list1 = is_swap ? &pos->last->swap : &pos->last->lru;
- list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
+ reservation_object_assert_held(pos->last->resv);
+ list = is_swap ? &pos->last->swap : &pos->last->lru;
+ list_cut_position(&entries, lru, list);
+
+ reservation_object_assert_held(pos->first->resv);
+ list = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
+ list_cut_position(&before, &entries, list);
- list_cut_position(&entries, lru, list1);
- list_cut_position(&before, &entries, list2);
list_splice(&before, lru);
list_splice_tail(&entries, lru);
}
--
2.14.1
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^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH 2/3] drm/amdgpu: fix "use bulk moves for efficient VM LRU handling" v2
[not found] ` <20180831131019.2486-1-christian.koenig-5C7GfCeVMHo@public.gmane.org>
@ 2018-08-31 13:10 ` Christian König
[not found] ` <20180831131019.2486-2-christian.koenig-5C7GfCeVMHo@public.gmane.org>
2018-08-31 13:10 ` [PATCH 3/3] drm/amdgpu: fix idle state and bulk_moveavle flag Christian König
` (2 subsequent siblings)
3 siblings, 1 reply; 14+ messages in thread
From: Christian König @ 2018-08-31 13:10 UTC (permalink / raw)
To: amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW; +Cc: michel.daenzer-5C7GfCeVMHo
First step to fix the LRU corruption, we accidentially tried to move things
on the LRU after dropping the lock.
Signed-off-by: Christian König <christian.koenig@amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index dd734970e167..349dcc37ee64 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -1237,6 +1237,8 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
ring = to_amdgpu_ring(entity->rq->sched);
amdgpu_ring_priority_get(ring, priority);
+ amdgpu_vm_move_to_lru_tail(p->adev, &fpriv->vm);
+
ttm_eu_fence_buffer_objects(&p->ticket, &p->validated, p->fence);
amdgpu_mn_unlock(p->mn);
@@ -1258,7 +1260,6 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
union drm_amdgpu_cs *cs = data;
struct amdgpu_cs_parser parser = {};
bool reserved_buffers = false;
- struct amdgpu_fpriv *fpriv;
int i, r;
if (!adev->accel_working)
@@ -1303,8 +1304,6 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
r = amdgpu_cs_submit(&parser, cs);
- fpriv = filp->driver_priv;
- amdgpu_vm_move_to_lru_tail(adev, &fpriv->vm);
out:
amdgpu_cs_parser_fini(&parser, r, reserved_buffers);
return r;
--
2.14.1
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^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH 3/3] drm/amdgpu: fix idle state and bulk_moveavle flag
[not found] ` <20180831131019.2486-1-christian.koenig-5C7GfCeVMHo@public.gmane.org>
2018-08-31 13:10 ` [PATCH 2/3] drm/amdgpu: fix "use bulk moves for efficient VM LRU handling" v2 Christian König
@ 2018-08-31 13:10 ` Christian König
[not found] ` <20180831131019.2486-3-christian.koenig-5C7GfCeVMHo@public.gmane.org>
2018-08-31 15:15 ` [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper Michel Dänzer
2018-09-03 2:05 ` Zhang, Jerry (Junwei)
3 siblings, 1 reply; 14+ messages in thread
From: Christian König @ 2018-08-31 13:10 UTC (permalink / raw)
To: amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW; +Cc: michel.daenzer-5C7GfCeVMHo
Add BOs to the idle state again and correctly clear the flag when
new BOs are added.
Signed-off-by: Christian König <christian.koenig@amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index f31fa351caba..d59222fb5931 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -156,12 +156,15 @@ static void amdgpu_vm_bo_base_init(struct amdgpu_vm_bo_base *base,
return;
list_add_tail(&base->bo_list, &bo->va);
- if (bo->tbo.type == ttm_bo_type_kernel)
- list_move(&base->vm_status, &vm->relocated);
-
if (bo->tbo.resv != vm->root.base.bo->tbo.resv)
return;
+ vm->bulk_moveable = false;
+ if (bo->tbo.type == ttm_bo_type_kernel)
+ list_move(&base->vm_status, &vm->relocated);
+ else
+ list_move(&base->vm_status, &vm->idle);
+
if (bo->preferred_domains &
amdgpu_mem_type_to_domain(bo->tbo.mem.mem_type))
return;
@@ -1121,7 +1124,7 @@ int amdgpu_vm_update_directories(struct amdgpu_device *adev,
struct amdgpu_vm_bo_base,
vm_status);
bo_base->moved = false;
- list_del_init(&bo_base->vm_status);
+ list_move(&bo_base->vm_status, &vm->idle);
bo = bo_base->bo->parent;
if (!bo)
@@ -2646,7 +2649,6 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm,
return r;
vm->pte_support_ats = false;
- vm->bulk_moveable = true;
if (vm_context == AMDGPU_VM_CONTEXT_COMPUTE) {
vm->use_cpu_for_update = !!(adev->vm_manager.vm_update_mode &
--
2.14.1
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^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper
[not found] ` <20180831131019.2486-1-christian.koenig-5C7GfCeVMHo@public.gmane.org>
2018-08-31 13:10 ` [PATCH 2/3] drm/amdgpu: fix "use bulk moves for efficient VM LRU handling" v2 Christian König
2018-08-31 13:10 ` [PATCH 3/3] drm/amdgpu: fix idle state and bulk_moveavle flag Christian König
@ 2018-08-31 15:15 ` Michel Dänzer
[not found] ` <a186be44-e64b-f408-fa30-bb81b59322f6-otUistvHUpPR7s880joybQ@public.gmane.org>
2018-09-03 2:05 ` Zhang, Jerry (Junwei)
3 siblings, 1 reply; 14+ messages in thread
From: Michel Dänzer @ 2018-08-31 15:15 UTC (permalink / raw)
To: Christian König; +Cc: amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW
On 2018-08-31 3:10 p.m., Christian König wrote:
> Staring at the function for six hours, just to essentially move one line
> of code.
That sucks, but the commit log should describe what the problem was and
how this patch solves it.
> Signed-off-by: Christian König <christian.koenig@amd.com>
> ---
> drivers/gpu/drm/ttm/ttm_bo.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 35d53d81f486..138c98902033 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -250,15 +250,18 @@ EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
> static void ttm_bo_bulk_move_helper(struct ttm_lru_bulk_move_pos *pos,
> struct list_head *lru, bool is_swap)
> {
> + struct list_head *list;
> LIST_HEAD(entries);
> LIST_HEAD(before);
> - struct list_head *list1, *list2;
>
> - list1 = is_swap ? &pos->last->swap : &pos->last->lru;
> - list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
> + reservation_object_assert_held(pos->last->resv);
> + list = is_swap ? &pos->last->swap : &pos->last->lru;
> + list_cut_position(&entries, lru, list);
> +
> + reservation_object_assert_held(pos->first->resv);
> + list = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
> + list_cut_position(&before, &entries, list);
So the problem was that the first list_cut_position call could result in
list2 pointing to la-la-land? Good catch!
--
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer
_______________________________________________
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amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper
[not found] ` <a186be44-e64b-f408-fa30-bb81b59322f6-otUistvHUpPR7s880joybQ@public.gmane.org>
@ 2018-08-31 15:17 ` Christian König
[not found] ` <c8d0d5c6-1221-26be-4005-2f7ae21ade80-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
0 siblings, 1 reply; 14+ messages in thread
From: Christian König @ 2018-08-31 15:17 UTC (permalink / raw)
To: Michel Dänzer; +Cc: amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW
Am 31.08.2018 um 17:15 schrieb Michel Dänzer:
> On 2018-08-31 3:10 p.m., Christian König wrote:
>> Staring at the function for six hours, just to essentially move one line
>> of code.
> That sucks, but the commit log should describe what the problem was and
> how this patch solves it.
>
>
>> Signed-off-by: Christian König <christian.koenig@amd.com>
>> ---
>> drivers/gpu/drm/ttm/ttm_bo.c | 13 ++++++++-----
>> 1 file changed, 8 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
>> index 35d53d81f486..138c98902033 100644
>> --- a/drivers/gpu/drm/ttm/ttm_bo.c
>> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
>> @@ -250,15 +250,18 @@ EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
>> static void ttm_bo_bulk_move_helper(struct ttm_lru_bulk_move_pos *pos,
>> struct list_head *lru, bool is_swap)
>> {
>> + struct list_head *list;
>> LIST_HEAD(entries);
>> LIST_HEAD(before);
>> - struct list_head *list1, *list2;
>>
>> - list1 = is_swap ? &pos->last->swap : &pos->last->lru;
>> - list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
>> + reservation_object_assert_held(pos->last->resv);
>> + list = is_swap ? &pos->last->swap : &pos->last->lru;
>> + list_cut_position(&entries, lru, list);
>> +
>> + reservation_object_assert_held(pos->first->resv);
>> + list = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
>> + list_cut_position(&before, &entries, list);
> So the problem was that the first list_cut_position call could result in
> list2 pointing to la-la-land? Good catch!
Yes, exactly. Thought that would be obvious, but going to add that to
the commit log.
Can I get a tested-by? You where much better at reproducing that than I'm.
Christian.
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 3/3] drm/amdgpu: fix idle state and bulk_moveavle flag
[not found] ` <20180831131019.2486-3-christian.koenig-5C7GfCeVMHo@public.gmane.org>
@ 2018-08-31 15:19 ` Michel Dänzer
0 siblings, 0 replies; 14+ messages in thread
From: Michel Dänzer @ 2018-08-31 15:19 UTC (permalink / raw)
To: Christian König; +Cc: amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW
On 2018-08-31 3:10 p.m., Christian König wrote:
> Add BOs to the idle state again and correctly clear the flag when
> new BOs are added.
>
> Signed-off-by: Christian König <christian.koenig@amd.com>
Typo in the shortlog: bulk_moveavle -> bulk_moveable
The series is
Tested-by: Michel Dänzer <michel.daenzer@amd.com>
Thanks Christian!
--
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper
[not found] ` <20180831131019.2486-1-christian.koenig-5C7GfCeVMHo@public.gmane.org>
` (2 preceding siblings ...)
2018-08-31 15:15 ` [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper Michel Dänzer
@ 2018-09-03 2:05 ` Zhang, Jerry (Junwei)
3 siblings, 0 replies; 14+ messages in thread
From: Zhang, Jerry (Junwei) @ 2018-09-03 2:05 UTC (permalink / raw)
To: Christian König, amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW
Cc: michel.daenzer-5C7GfCeVMHo
On 08/31/2018 09:10 PM, Christian König wrote:
> Staring at the function for six hours, just to essentially move one line
> of code.
>
> Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Junwei Zhang <Jerry.Zhang@amd.com>
> ---
> drivers/gpu/drm/ttm/ttm_bo.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 35d53d81f486..138c98902033 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -250,15 +250,18 @@ EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
> static void ttm_bo_bulk_move_helper(struct ttm_lru_bulk_move_pos *pos,
> struct list_head *lru, bool is_swap)
> {
> + struct list_head *list;
> LIST_HEAD(entries);
> LIST_HEAD(before);
> - struct list_head *list1, *list2;
>
> - list1 = is_swap ? &pos->last->swap : &pos->last->lru;
> - list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
> + reservation_object_assert_held(pos->last->resv);
> + list = is_swap ? &pos->last->swap : &pos->last->lru;
> + list_cut_position(&entries, lru, list);
> +
> + reservation_object_assert_held(pos->first->resv);
> + list = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
> + list_cut_position(&before, &entries, list);
>
> - list_cut_position(&entries, lru, list1);
> - list_cut_position(&before, &entries, list2);
> list_splice(&before, lru);
> list_splice_tail(&entries, lru);
> }
>
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 2/3] drm/amdgpu: fix "use bulk moves for efficient VM LRU handling" v2
[not found] ` <20180831131019.2486-2-christian.koenig-5C7GfCeVMHo@public.gmane.org>
@ 2018-09-03 2:05 ` Zhang, Jerry (Junwei)
0 siblings, 0 replies; 14+ messages in thread
From: Zhang, Jerry (Junwei) @ 2018-09-03 2:05 UTC (permalink / raw)
To: Christian König, amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW
Cc: michel.daenzer-5C7GfCeVMHo
On 08/31/2018 09:10 PM, Christian König wrote:
> First step to fix the LRU corruption, we accidentially tried to move things
> on the LRU after dropping the lock.
>
> Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Junwei Zhang <Jerry.Zhang@amd.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> index dd734970e167..349dcc37ee64 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
> @@ -1237,6 +1237,8 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
> ring = to_amdgpu_ring(entity->rq->sched);
> amdgpu_ring_priority_get(ring, priority);
>
> + amdgpu_vm_move_to_lru_tail(p->adev, &fpriv->vm);
> +
> ttm_eu_fence_buffer_objects(&p->ticket, &p->validated, p->fence);
> amdgpu_mn_unlock(p->mn);
>
> @@ -1258,7 +1260,6 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
> union drm_amdgpu_cs *cs = data;
> struct amdgpu_cs_parser parser = {};
> bool reserved_buffers = false;
> - struct amdgpu_fpriv *fpriv;
> int i, r;
>
> if (!adev->accel_working)
> @@ -1303,8 +1304,6 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
>
> r = amdgpu_cs_submit(&parser, cs);
>
> - fpriv = filp->driver_priv;
> - amdgpu_vm_move_to_lru_tail(adev, &fpriv->vm);
> out:
> amdgpu_cs_parser_fini(&parser, r, reserved_buffers);
> return r;
>
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper
[not found] ` <c8d0d5c6-1221-26be-4005-2f7ae21ade80-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
@ 2018-09-06 10:02 ` Huang Rui
2018-09-06 10:06 ` Christian König
0 siblings, 1 reply; 14+ messages in thread
From: Huang Rui @ 2018-09-06 10:02 UTC (permalink / raw)
To: christian.koenig-5C7GfCeVMHo
Cc: Michel Dänzer, amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW
On Fri, Aug 31, 2018 at 05:17:33PM +0200, Christian König wrote:
> Am 31.08.2018 um 17:15 schrieb Michel Dänzer:
> >On 2018-08-31 3:10 p.m., Christian König wrote:
> >>Staring at the function for six hours, just to essentially move one line
> >>of code.
> >That sucks, but the commit log should describe what the problem was and
> >how this patch solves it.
> >
> >
> >>Signed-off-by: Christian König <christian.koenig@amd.com>
> >>---
> >> drivers/gpu/drm/ttm/ttm_bo.c | 13 ++++++++-----
> >> 1 file changed, 8 insertions(+), 5 deletions(-)
> >>
> >>diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> >>index 35d53d81f486..138c98902033 100644
> >>--- a/drivers/gpu/drm/ttm/ttm_bo.c
> >>+++ b/drivers/gpu/drm/ttm/ttm_bo.c
> >>@@ -250,15 +250,18 @@ EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
> >> static void ttm_bo_bulk_move_helper(struct ttm_lru_bulk_move_pos *pos,
> >> struct list_head *lru, bool is_swap)
> >> {
> >>+ struct list_head *list;
> >> LIST_HEAD(entries);
> >> LIST_HEAD(before);
> >>- struct list_head *list1, *list2;
> >>- list1 = is_swap ? &pos->last->swap : &pos->last->lru;
> >>- list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
> >>+ reservation_object_assert_held(pos->last->resv);
> >>+ list = is_swap ? &pos->last->swap : &pos->last->lru;
> >>+ list_cut_position(&entries, lru, list);
> >>+
> >>+ reservation_object_assert_held(pos->first->resv);
> >>+ list = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
> >>+ list_cut_position(&before, &entries, list);
> >So the problem was that the first list_cut_position call could result in
> >list2 pointing to la-la-land? Good catch!
>
> Yes, exactly. Thought that would be obvious, but going to add that
> to the commit log.
>
> Can I get a tested-by? You where much better at reproducing that than I'm.
>
Michel, Christian, thanks so much to take care of this when I was on
vacation. And sorry to let you take a long time for finding the cause.
Is that because I didn't hold the resveration before cut the list from
position "first" and "last"? May I know in which cases, we must hold the
bo's reservation firstly?
Thanks,
Ray
_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper
2018-09-06 10:02 ` Huang Rui
@ 2018-09-06 10:06 ` Christian König
[not found] ` <3be7e67a-2ffe-21c0-2160-69a330413858-5C7GfCeVMHo@public.gmane.org>
0 siblings, 1 reply; 14+ messages in thread
From: Christian König @ 2018-09-06 10:06 UTC (permalink / raw)
To: Huang Rui; +Cc: Michel Dänzer, amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW
Am 06.09.2018 um 12:02 schrieb Huang Rui:
> On Fri, Aug 31, 2018 at 05:17:33PM +0200, Christian König wrote:
>> Am 31.08.2018 um 17:15 schrieb Michel Dänzer:
>>> On 2018-08-31 3:10 p.m., Christian König wrote:
>>>> Staring at the function for six hours, just to essentially move one line
>>>> of code.
>>> That sucks, but the commit log should describe what the problem was and
>>> how this patch solves it.
>>>
>>>
>>>> Signed-off-by: Christian König <christian.koenig@amd.com>
>>>> ---
>>>> drivers/gpu/drm/ttm/ttm_bo.c | 13 ++++++++-----
>>>> 1 file changed, 8 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
>>>> index 35d53d81f486..138c98902033 100644
>>>> --- a/drivers/gpu/drm/ttm/ttm_bo.c
>>>> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
>>>> @@ -250,15 +250,18 @@ EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
>>>> static void ttm_bo_bulk_move_helper(struct ttm_lru_bulk_move_pos *pos,
>>>> struct list_head *lru, bool is_swap)
>>>> {
>>>> + struct list_head *list;
>>>> LIST_HEAD(entries);
>>>> LIST_HEAD(before);
>>>> - struct list_head *list1, *list2;
>>>> - list1 = is_swap ? &pos->last->swap : &pos->last->lru;
>>>> - list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
>>>> + reservation_object_assert_held(pos->last->resv);
>>>> + list = is_swap ? &pos->last->swap : &pos->last->lru;
>>>> + list_cut_position(&entries, lru, list);
>>>> +
>>>> + reservation_object_assert_held(pos->first->resv);
>>>> + list = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
>>>> + list_cut_position(&before, &entries, list);
>>> So the problem was that the first list_cut_position call could result in
>>> list2 pointing to la-la-land? Good catch!
>> Yes, exactly. Thought that would be obvious, but going to add that
>> to the commit log.
>>
>> Can I get a tested-by? You where much better at reproducing that than I'm.
>>
> Michel, Christian, thanks so much to take care of this when I was on
> vacation. And sorry to let you take a long time for finding the cause.
>
> Is that because I didn't hold the resveration before cut the list from
> position "first" and "last"?
Yes, that was one problem. Another was that the cutting code was buggy
and determined one of the positions to cut at the wrong time.
> May I know in which cases, we must hold the
> bo's reservation firstly?
BOs are reserved to prevent moving them. E.g. when the BO isn't reserved
it can move around and so the LRU where you want to add/remove it could
change.
Christian.
>
> Thanks,
> Ray
>
>
_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper
[not found] ` <3be7e67a-2ffe-21c0-2160-69a330413858-5C7GfCeVMHo@public.gmane.org>
@ 2018-09-07 11:02 ` Huang, Ray
[not found] ` <CY1PR12MB0043539F7EE805B3A98E1FE2EC000-1s8aH8ViOEdbUNsZNX5b0gdYzm3356FpvxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
0 siblings, 1 reply; 14+ messages in thread
From: Huang, Ray @ 2018-09-07 11:02 UTC (permalink / raw)
To: Koenig, Christian
Cc: Michel Dänzer, amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW
[-- Attachment #1: Type: text/plain, Size: 4061 bytes --]
>> Yes, that was one problem. Another was that the cutting code was buggy
>> and determined one of the positions to cut at the wrong time.
I went through again about the list cutting behavior and wrote down with the attached picture.
After do the second list_cut_position, the list2 should be point the end of "before" list. And list2 won't be used anymore after list cutting. May I know am I something missed?
Thanks,
Ray
From: amd-gfx <amd-gfx-bounces-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org> on behalf of Christian König <christian.koenig-5C7GfCeVMHo@public.gmane.org>
Sent: Thursday, September 6, 2018 6:06 PM
To: Huang, Ray
Cc: Michel Dänzer; amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
Subject: Re: [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper
Am 06.09.2018 um 12:02 schrieb Huang Rui:
> On Fri, Aug 31, 2018 at 05:17:33PM +0200, Christian König wrote:
>> Am 31.08.2018 um 17:15 schrieb Michel Dänzer:
>>> On 2018-08-31 3:10 p.m., Christian König wrote:
>>>> Staring at the function for six hours, just to essentially move one line
>>>> of code.
>>> That sucks, but the commit log should describe what the problem was and
>>> how this patch solves it.
>>>
>>>
>>>> Signed-off-by: Christian König <christian.koenig-5C7GfCeVMHo@public.gmane.org>
>>>> ---
>>>> drivers/gpu/drm/ttm/ttm_bo.c | 13 ++++++++-----
>>>> 1 file changed, 8 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
>>>> index 35d53d81f486..138c98902033 100644
>>>> --- a/drivers/gpu/drm/ttm/ttm_bo.c
>>>> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
>>>> @@ -250,15 +250,18 @@ EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
>>>> static void ttm_bo_bulk_move_helper(struct ttm_lru_bulk_move_pos *pos,
>>>> struct list_head *lru, bool is_swap)
>>>> {
>>>> + struct list_head *list;
>>>> LIST_HEAD(entries);
>>>> LIST_HEAD(before);
>>>> - struct list_head *list1, *list2;
>>>> - list1 = is_swap ? &pos->last->swap : &pos->last->lru;
>>>> - list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
>>>> + reservation_object_assert_held(pos->last->resv);
>>>> + list = is_swap ? &pos->last->swap : &pos->last->lru;
>>>> + list_cut_position(&entries, lru, list);
>>>> +
>>>> + reservation_object_assert_held(pos->first->resv);
>>>> + list = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
>>>> + list_cut_position(&before, &entries, list);
>>> So the problem was that the first list_cut_position call could result in
>>> list2 pointing to la-la-land? Good catch!
>> Yes, exactly. Thought that would be obvious, but going to add that
>> to the commit log.
>>
>> Can I get a tested-by? You where much better at reproducing that than I'm.
>>
> Michel, Christian, thanks so much to take care of this when I was on
> vacation. And sorry to let you take a long time for finding the cause.
>
> Is that because I didn't hold the resveration before cut the list from
> position "first" and "last"?
Yes, that was one problem. Another was that the cutting code was buggy
and determined one of the positions to cut at the wrong time.
> May I know in which cases, we must hold the
> bo's reservation firstly?
BOs are reserved to prevent moving them. E.g. when the BO isn't reserved
it can move around and so the LRU where you want to add/remove it could
change.
Christian.
>
> Thanks,
> Ray
>
>
_______________________________________________
amd-gfx mailing list
amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx
amd-gfx Info Page - freedesktop.org
lists.freedesktop.org
To see the collection of prior postings to the list, visit the amd-gfx Archives.. Using amd-gfx: To post a message to all the list members, send email to amd-gfx-PD4FTy7X32lNgt0PjOBp9xlNPtJONSTn@public.gmane.org You can subscribe to the list, or change your existing subscription, in the sections below.
[-- Attachment #2: list_cutting.jpg --]
[-- Type: image/jpeg, Size: 107697 bytes --]
[-- Attachment #3: Type: text/plain, Size: 154 bytes --]
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper
[not found] ` <CY1PR12MB0043539F7EE805B3A98E1FE2EC000-1s8aH8ViOEdbUNsZNX5b0gdYzm3356FpvxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
@ 2018-09-07 11:18 ` Christian König
[not found] ` <24dbe7c4-63df-b8a7-28c3-df0e9866841f-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
0 siblings, 1 reply; 14+ messages in thread
From: Christian König @ 2018-09-07 11:18 UTC (permalink / raw)
To: Huang, Ray, Koenig, Christian
Cc: Michel Dänzer, amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW
[-- Attachment #1.1: Type: text/plain, Size: 4793 bytes --]
Am 07.09.2018 um 13:02 schrieb Huang, Ray:
>>> Yes, that was one problem. Another was that the cutting code was buggy
>>> and determined one of the positions to cut at the wrong time.
> I went through again about the list cutting behavior and wrote down with the attached picture.
> After do the second list_cut_position, the list2 should be point the end of "before" list. And list2 won't be used anymore after list cutting. May I know am I something missed?
Let's take a look at the original code:
> list1 = is_swap ? &pos->last->swap : &pos->last->lru;
> list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
>
> list_cut_position(&entries, lru, list1);
> list_cut_position(&before, &entries, list2);
As far as I can see the problem is that the first list_cur_position
could modify the value of pos->first->lru.prev and so make the second
list_cut_position work on the wrong position.
Regards,
Christian.
>
> Thanks,
> Ray
>
> From: amd-gfx <amd-gfx-bounces-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org> on behalf of Christian König <christian.koenig-5C7GfCeVMHo@public.gmane.org>
> Sent: Thursday, September 6, 2018 6:06 PM
> To: Huang, Ray
> Cc: Michel Dänzer; amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
> Subject: Re: [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper
>
>
> Am 06.09.2018 um 12:02 schrieb Huang Rui:
>> On Fri, Aug 31, 2018 at 05:17:33PM +0200, Christian König wrote:
>>> Am 31.08.2018 um 17:15 schrieb Michel Dänzer:
>>>> On 2018-08-31 3:10 p.m., Christian König wrote:
>>>>> Staring at the function for six hours, just to essentially move one line
>>>>> of code.
>>>> That sucks, but the commit log should describe what the problem was and
>>>> how this patch solves it.
>>>>
>>>>
>>>>> Signed-off-by: Christian König <christian.koenig-5C7GfCeVMHo@public.gmane.org>
>>>>> ---
>>>>> drivers/gpu/drm/ttm/ttm_bo.c | 13 ++++++++-----
>>>>> 1 file changed, 8 insertions(+), 5 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
>>>>> index 35d53d81f486..138c98902033 100644
>>>>> --- a/drivers/gpu/drm/ttm/ttm_bo.c
>>>>> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
>>>>> @@ -250,15 +250,18 @@ EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
>>>>> static void ttm_bo_bulk_move_helper(struct ttm_lru_bulk_move_pos *pos,
>>>>> struct list_head *lru, bool is_swap)
>>>>> {
>>>>> + struct list_head *list;
>>>>> LIST_HEAD(entries);
>>>>> LIST_HEAD(before);
>>>>> - struct list_head *list1, *list2;
>>>>> - list1 = is_swap ? &pos->last->swap : &pos->last->lru;
>>>>> - list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
>>>>> + reservation_object_assert_held(pos->last->resv);
>>>>> + list = is_swap ? &pos->last->swap : &pos->last->lru;
>>>>> + list_cut_position(&entries, lru, list);
>>>>> +
>>>>> + reservation_object_assert_held(pos->first->resv);
>>>>> + list = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
>>>>> + list_cut_position(&before, &entries, list);
>>>> So the problem was that the first list_cut_position call could result in
>>>> list2 pointing to la-la-land? Good catch!
>>> Yes, exactly. Thought that would be obvious, but going to add that
>>> to the commit log.
>>>
>>> Can I get a tested-by? You where much better at reproducing that than I'm.
>>>
>> Michel, Christian, thanks so much to take care of this when I was on
>> vacation. And sorry to let you take a long time for finding the cause.
>>
>> Is that because I didn't hold the resveration before cut the list from
>> position "first" and "last"?
> Yes, that was one problem. Another was that the cutting code was buggy
> and determined one of the positions to cut at the wrong time.
>
>> May I know in which cases, we must hold the
>> bo's reservation firstly?
> BOs are reserved to prevent moving them. E.g. when the BO isn't reserved
> it can move around and so the LRU where you want to add/remove it could
> change.
>
> Christian.
>
>> Thanks,
>> Ray
>>
>>
> _______________________________________________
> amd-gfx mailing list
> amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>
>
> amd-gfx Info Page - freedesktop.org
> lists.freedesktop.org
> To see the collection of prior postings to the list, visit the amd-gfx Archives.. Using amd-gfx: To post a message to all the list members, send email to amd-gfx-PD4FTy7X32lNgt0PjOBp9xlNPtJONSTn@public.gmane.org You can subscribe to the list, or change your existing subscription, in the sections below.
>
>
>
>
> _______________________________________________
> amd-gfx mailing list
> amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
[-- Attachment #1.2: Type: text/html, Size: 7434 bytes --]
[-- Attachment #2: Type: text/plain, Size: 154 bytes --]
_______________________________________________
amd-gfx mailing list
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https://lists.freedesktop.org/mailman/listinfo/amd-gfx
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper
[not found] ` <24dbe7c4-63df-b8a7-28c3-df0e9866841f-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
@ 2018-09-08 7:54 ` Huang Rui
2018-09-08 10:43 ` Christian König
0 siblings, 1 reply; 14+ messages in thread
From: Huang Rui @ 2018-09-08 7:54 UTC (permalink / raw)
To: Koenig, Christian
Cc: Michel D�nzer, amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW
[-- Attachment #1: Type: text/plain, Size: 6406 bytes --]
On Fri, Sep 07, 2018 at 07:18:59PM +0800, Christian K�nig wrote:
> Am 07.09.2018 um 13:02 schrieb Huang, Ray:
>
> Yes, that was one problem. Another was that the cutting code was buggy
> and determined one of the positions to cut at the wrong time.
>
> I went through again about the list cutting behavior and wrote down with the attached picture.
> After do the second list_cut_position, the list2 should be point the end of "before" list. And list2 won't be used anymore after list cutting. May I know am I something missed?
>
>
> Let's take a look at the original code:
>
> list1 = is_swap ? &pos->last->swap : &pos->last->lru;
> list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
>
> list_cut_position(&entries, lru, list1);
> list_cut_position(&before, &entries, list2);
>
>
> As far as I can see the problem is that the first list_cur_position could
> modify the value of pos->first->lru.prev and so make the second
> list_cut_position work on the wrong position.
>
I think I understood. In this case (the first element of LRU ==
pos->first->lru), please see the picture. If we store first->lru.prev as
list2(LRU head), after do list cutting, the first->lru.prev will overwrite
as new head (entries), however, the orignal list2 will still point previous
head (that is the wrong position now). We actually expected to use the
latest first->lru.prev as the second cutting position. So we should adjust
code sequence like below:
list1 = is_swap ? &pos->last->swap : &pos->last->lru;
list_cut_position(&entries, lru, list1);
list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
list_cut_position(&before, &entries, list2);
Am I understanding right?
Thanks,
Ray
> Regards,
> Christian.
>
>
>
> Thanks,
> Ray
>
> From: amd-gfx <amd-gfx-bounces-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org> on behalf of Christian König <christian.koenig-5C7GfCeVMHo@public.gmane.org>
> Sent: Thursday, September 6, 2018 6:06 PM
> To: Huang, Ray
> Cc: Michel Dänzer; amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
> Subject: Re: [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper
>
>
> Am 06.09.2018 um 12:02 schrieb Huang Rui:
>
> On Fri, Aug 31, 2018 at 05:17:33PM +0200, Christian König wrote:
>
> Am 31.08.2018 um 17:15 schrieb Michel Dänzer:
>
> On 2018-08-31 3:10 p.m., Christian König wrote:
>
> Staring at the function for six hours, just to essentially move one line
> of code.
>
> That sucks, but the commit log should describe what the problem was and
> how this patch solves it.
>
>
>
> Signed-off-by: Christian König <christian.koenig-5C7GfCeVMHo@public.gmane.org>
> ---
> drivers/gpu/drm/ttm/ttm_bo.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
> index 35d53d81f486..138c98902033 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
> @@ -250,15 +250,18 @@ EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
> static void ttm_bo_bulk_move_helper(struct ttm_lru_bulk_move_pos *pos,
> struct list_head *lru, bool is_swap)
> {
> + struct list_head *list;
> LIST_HEAD(entries);
> LIST_HEAD(before);
> - struct list_head *list1, *list2;
> - list1 = is_swap ? &pos->last->swap : &pos->last->lru;
> - list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
> + reservation_object_assert_held(pos->last->resv);
> + list = is_swap ? &pos->last->swap : &pos->last->lru;
> + list_cut_position(&entries, lru, list);
> +
> + reservation_object_assert_held(pos->first->resv);
> + list = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
> + list_cut_position(&before, &entries, list);
>
> So the problem was that the first list_cut_position call could result in
> list2 pointing to la-la-land? Good catch!
>
> Yes, exactly. Thought that would be obvious, but going to add that
> to the commit log.
>
> Can I get a tested-by? You where much better at reproducing that than I'm.
>
>
> Michel, Christian, thanks so much to take care of this when I was on
> vacation. And sorry to let you take a long time for finding the cause.
>
> Is that because I didn't hold the resveration before cut the list from
> position "first" and "last"?
>
> Yes, that was one problem. Another was that the cutting code was buggy
> and determined one of the positions to cut at the wrong time.
>
>
> May I know in which cases, we must hold the
> bo's reservation firstly?
>
> BOs are reserved to prevent moving them. E.g. when the BO isn't reserved
> it can move around and so the LRU where you want to add/remove it could
> change.
>
> Christian.
>
>
> Thanks,
> Ray
>
>
>
> _______________________________________________
> amd-gfx mailing list
> amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>
>
> amd-gfx Info Page - freedesktop.org
> lists.freedesktop.org
> To see the collection of prior postings to the list, visit the amd-gfx Archives.. Using amd-gfx: To post a message to all the list members, send email to amd-gfx-PD4FTy7X32lNgt0PjOBp9xlNPtJONSTn@public.gmane.org You can subscribe to the list, or change your existing subscription, in the sections below.
>
>
>
>
>
> _______________________________________________
> amd-gfx mailing list
> amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>
>
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^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper
2018-09-08 7:54 ` Huang Rui
@ 2018-09-08 10:43 ` Christian König
0 siblings, 0 replies; 14+ messages in thread
From: Christian König @ 2018-09-08 10:43 UTC (permalink / raw)
To: Huang Rui; +Cc: Michel D�nzer, amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW
Am 08.09.2018 um 09:54 schrieb Huang Rui:
> On Fri, Sep 07, 2018 at 07:18:59PM +0800, Christian K�nig wrote:
>> Am 07.09.2018 um 13:02 schrieb Huang, Ray:
>>
>> Yes, that was one problem. Another was that the cutting code was buggy
>> and determined one of the positions to cut at the wrong time.
>>
>> I went through again about the list cutting behavior and wrote down with the attached picture.
>> After do the second list_cut_position, the list2 should be point the end of "before" list. And list2 won't be used anymore after list cutting. May I know am I something missed?
>>
>>
>> Let's take a look at the original code:
>>
>> list1 = is_swap ? &pos->last->swap : &pos->last->lru;
>> list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
>>
>> list_cut_position(&entries, lru, list1);
>> list_cut_position(&before, &entries, list2);
>>
>>
>> As far as I can see the problem is that the first list_cur_position could
>> modify the value of pos->first->lru.prev and so make the second
>> list_cut_position work on the wrong position.
>>
> I think I understood. In this case (the first element of LRU ==
> pos->first->lru), please see the picture. If we store first->lru.prev as
> list2(LRU head), after do list cutting, the first->lru.prev will overwrite
> as new head (entries), however, the orignal list2 will still point previous
> head (that is the wrong position now). We actually expected to use the
> latest first->lru.prev as the second cutting position. So we should adjust
> code sequence like below:
>
> list1 = is_swap ? &pos->last->swap : &pos->last->lru;
> list_cut_position(&entries, lru, list1);
>
> list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
> list_cut_position(&before, &entries, list2);
>
> Am I understanding right?
Yes, exactly. And the fix looks like what I did as well. Just only used
one variable and added some extra BUG_ON().
Christian.
>
> Thanks,
> Ray
>
>> Regards,
>> Christian.
>>
>>
>>
>> Thanks,
>> Ray
>>
>> From: amd-gfx <amd-gfx-bounces@lists.freedesktop.org> on behalf of Christian König <christian.koenig@amd.com>
>> Sent: Thursday, September 6, 2018 6:06 PM
>> To: Huang, Ray
>> Cc: Michel Dänzer; amd-gfx@lists.freedesktop.org
>> Subject: Re: [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper
>>
>>
>> Am 06.09.2018 um 12:02 schrieb Huang Rui:
>>
>> On Fri, Aug 31, 2018 at 05:17:33PM +0200, Christian König wrote:
>>
>> Am 31.08.2018 um 17:15 schrieb Michel Dänzer:
>>
>> On 2018-08-31 3:10 p.m., Christian König wrote:
>>
>> Staring at the function for six hours, just to essentially move one line
>> of code.
>>
>> That sucks, but the commit log should describe what the problem was and
>> how this patch solves it.
>>
>>
>>
>> Signed-off-by: Christian König <christian.koenig@amd.com>
>> ---
>> drivers/gpu/drm/ttm/ttm_bo.c | 13 ++++++++-----
>> 1 file changed, 8 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
>> index 35d53d81f486..138c98902033 100644
>> --- a/drivers/gpu/drm/ttm/ttm_bo.c
>> +++ b/drivers/gpu/drm/ttm/ttm_bo.c
>> @@ -250,15 +250,18 @@ EXPORT_SYMBOL(ttm_bo_move_to_lru_tail);
>> static void ttm_bo_bulk_move_helper(struct ttm_lru_bulk_move_pos *pos,
>> struct list_head *lru, bool is_swap)
>> {
>> + struct list_head *list;
>> LIST_HEAD(entries);
>> LIST_HEAD(before);
>> - struct list_head *list1, *list2;
>> - list1 = is_swap ? &pos->last->swap : &pos->last->lru;
>> - list2 = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
>> + reservation_object_assert_held(pos->last->resv);
>> + list = is_swap ? &pos->last->swap : &pos->last->lru;
>> + list_cut_position(&entries, lru, list);
>> +
>> + reservation_object_assert_held(pos->first->resv);
>> + list = is_swap ? pos->first->swap.prev : pos->first->lru.prev;
>> + list_cut_position(&before, &entries, list);
>>
>> So the problem was that the first list_cut_position call could result in
>> list2 pointing to la-la-land? Good catch!
>>
>> Yes, exactly. Thought that would be obvious, but going to add that
>> to the commit log.
>>
>> Can I get a tested-by? You where much better at reproducing that than I'm.
>>
>>
>> Michel, Christian, thanks so much to take care of this when I was on
>> vacation. And sorry to let you take a long time for finding the cause.
>>
>> Is that because I didn't hold the resveration before cut the list from
>> position "first" and "last"?
>>
>> Yes, that was one problem. Another was that the cutting code was buggy
>> and determined one of the positions to cut at the wrong time.
>>
>>
>> May I know in which cases, we must hold the
>> bo's reservation firstly?
>>
>> BOs are reserved to prevent moving them. E.g. when the BO isn't reserved
>> it can move around and so the LRU where you want to add/remove it could
>> change.
>>
>> Christian.
>>
>>
>> Thanks,
>> Ray
>>
>>
>>
>> _______________________________________________
>> amd-gfx mailing list
>> amd-gfx@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>>
>>
>> amd-gfx Info Page - freedesktop.org
>> lists.freedesktop.org
>> To see the collection of prior postings to the list, visit the amd-gfx Archives.. Using amd-gfx: To post a message to all the list members, send email to amd-gfx@lists.freedesktop.org. You can subscribe to the list, or change your existing subscription, in the sections below.
>>
>>
>>
>>
>>
>> _______________________________________________
>> amd-gfx mailing list
>> amd-gfx@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
>>
>>
_______________________________________________
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^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2018-09-08 10:43 UTC | newest]
Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-08-31 13:10 [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper Christian König
[not found] ` <20180831131019.2486-1-christian.koenig-5C7GfCeVMHo@public.gmane.org>
2018-08-31 13:10 ` [PATCH 2/3] drm/amdgpu: fix "use bulk moves for efficient VM LRU handling" v2 Christian König
[not found] ` <20180831131019.2486-2-christian.koenig-5C7GfCeVMHo@public.gmane.org>
2018-09-03 2:05 ` Zhang, Jerry (Junwei)
2018-08-31 13:10 ` [PATCH 3/3] drm/amdgpu: fix idle state and bulk_moveavle flag Christian König
[not found] ` <20180831131019.2486-3-christian.koenig-5C7GfCeVMHo@public.gmane.org>
2018-08-31 15:19 ` Michel Dänzer
2018-08-31 15:15 ` [PATCH 1/3] drm/ttm: fix ttm_bo_bulk_move_helper Michel Dänzer
[not found] ` <a186be44-e64b-f408-fa30-bb81b59322f6-otUistvHUpPR7s880joybQ@public.gmane.org>
2018-08-31 15:17 ` Christian König
[not found] ` <c8d0d5c6-1221-26be-4005-2f7ae21ade80-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2018-09-06 10:02 ` Huang Rui
2018-09-06 10:06 ` Christian König
[not found] ` <3be7e67a-2ffe-21c0-2160-69a330413858-5C7GfCeVMHo@public.gmane.org>
2018-09-07 11:02 ` Huang, Ray
[not found] ` <CY1PR12MB0043539F7EE805B3A98E1FE2EC000-1s8aH8ViOEdbUNsZNX5b0gdYzm3356FpvxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
2018-09-07 11:18 ` Christian König
[not found] ` <24dbe7c4-63df-b8a7-28c3-df0e9866841f-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2018-09-08 7:54 ` Huang Rui
2018-09-08 10:43 ` Christian König
2018-09-03 2:05 ` Zhang, Jerry (Junwei)
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