On 04/24/2018 12:30 PM, Eric W. Biederman wrote:
"Panariti, David" <david.panar...@amd.com> writes:
Andrey Grodzovsky <andrey.grodzov...@amd.com> writes:
Kind of dma_fence_wait_killable, except that we don't have such API
(maybe worth adding ?)
Depends on how many places it would be called, or think it might be called.
Can always factor on the 2nd time it's needed.
Factoring, IMO, rarely hurts. The factored function can easily be visited using
`M-.' ;->
Also, if the wait could be very long, would a log message, something like "xxx has
run for Y seconds." help?
I personally hate hanging w/no info.
Ugh. This loop appears susceptible to loosing wake ups. There are
races between when a wake-up happens, when we clear the sleeping state,
and when we test the stat to see if we should stat awake. So yes
implementing a dma_fence_wait_killable that handles of all that
correctly sounds like an very good idea.
I am not clear here - could you be more specific about what races will
happen here, more bellow
Eric
If the ring is hanging for some reason allow to recover the waiting by sending
fatal signal.
Originally-by: David Panariti <david.panar...@amd.com>
Signed-off-by: Andrey Grodzovsky <andrey.grodzov...@amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
index eb80edf..37a36af 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
@@ -421,10 +421,16 @@ int amdgpu_ctx_wait_prev_fence(struct amdgpu_ctx *ctx,
unsigned ring_id)
if (other) {
signed long r;
- r = dma_fence_wait_timeout(other, false, MAX_SCHEDULE_TIMEOUT);
- if (r < 0) {
- DRM_ERROR("Error (%ld) waiting for fence!\n", r);
- return r;
+
+ while (true) {
+ if ((r = dma_fence_wait_timeout(other, true,
+ MAX_SCHEDULE_TIMEOUT)) >= 0)
+ return 0;
+
Do you mean that by the time I reach here some other thread from my
group already might dequeued SIGKILL since it's a shared signal and
hence fatal_signal_pending will return false ? Or are you talking about
the dma_fence_wait_timeout implementation in dma_fence_default_wait with
schedule_timeout ?
Andrey
+ if (fatal_signal_pending(current)) {
+ DRM_ERROR("Error (%ld) waiting for fence!\n", r);
+ return r;
+ }
}
}
--
2.7.4
Eric
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