On 2018年03月06日 13:59, Liu, Monk wrote:
- if (check->context == fence->context ||
+ if ((check->context == fence->context &&
+ dma_fence_is_later(fence, check)) ||
We still need do more for !dma_fence_is_later(fence, check) case, in which,
we will don't need add new fence to resv slot.
if ((check->context == fence->context) && dma_fence_is_later(fence, check))
fobj->shared_count = j;
RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence);
fobj->shared_count++;
} else {
dma_fence_put(fence);
}
No you cannot do that, check is changed and not the one you want,
Besides, we don't need to consider the case you mentioned, take only one fence in
obj->staged for example:
You add a fence whose context is equal to this fence (check), so current logic
will put this check into fobj->shared[++j],
Yes, if !dma_fence_is_later(fence, check), then 'check' will be put to
fobj->shared[++j], so we don't need add new fence to resv slot, don't we?
Regards,
David Zhou
so in the end
Obj->fence will point to fobj, and original old would be rcu_kfree()
No additional action actually needed...
/Monk
-----Original Message-----
From: Zhou, David(ChunMing)
Sent: 2018年3月6日 12:25
To: Liu, Monk <monk....@amd.com>; dri-de...@freedesktop.org
Subject: Re: [PATCH] dma-buf/reservation: should keep later one in add fence(v2)
On 2018年03月06日 11:53, Monk Liu wrote:
v2:
still check context first to avoid warning from dma_fence_is_later
apply this fix in add_shared_replace as well
Change-Id: If6a979ba9fd6c923b82212f35f07a9ff31c86767
Signed-off-by: Monk Liu <monk....@amd.com>
---
drivers/dma-buf/reservation.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/dma-buf/reservation.c
b/drivers/dma-buf/reservation.c index 314eb10..c6e3c86 100644
--- a/drivers/dma-buf/reservation.c
+++ b/drivers/dma-buf/reservation.c
@@ -118,7 +118,8 @@ reservation_object_add_shared_inplace(struct
reservation_object *obj,
old_fence = rcu_dereference_protected(fobj->shared[i],
reservation_object_held(obj));
- if (old_fence->context == fence->context) {
+ if (old_fence->context == fence->context &&
+ dma_fence_is_later(fence, old_fence)) {
/* memory barrier is added by write_seqcount_begin */
RCU_INIT_POINTER(fobj->shared[i], fence);
write_seqcount_end(&obj->seq);
@@ -179,7 +180,8 @@ reservation_object_add_shared_replace(struct
reservation_object *obj,
check = rcu_dereference_protected(old->shared[i],
reservation_object_held(obj));
- if (check->context == fence->context ||
+ if ((check->context == fence->context &&
+ dma_fence_is_later(fence, check)) ||
We still need do more for !dma_fence_is_later(fence, check) case, in which,
we will don't need add new fence to resv slot.
if ((check->context == fence->context) && dma_fence_is_later(fence, check))
fobj->shared_count = j;
RCU_INIT_POINTER(fobj->shared[fobj->shared_count], fence);
fobj->shared_count++;
} else {
dma_fence_put(fence);
}
Regards,
David Zhou
dma_fence_is_signaled(check))
RCU_INIT_POINTER(fobj->shared[--k], check);
else
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