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dma-buf: avoid scheduling on fence status query v2 

When a timeout of zero is specified, the caller is only interested in
the fence status.

In the current implementation, dma_fence_default_wait will always call
schedule_timeout() at least once for an unsignaled fence. This adds a
significant overhead to a fence status query.

Avoid this overhead by returning early if a zero timeout is specified.

v2: move early return after enable_signaling

Signed-off-by: Andres Rodriguez <andresx7@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170426144620.3560-1-andresx7@gmail.com
This commit is contained in:
Andres Rodriguez 2017-04-26 10:46:20 -04:00 committed by Gustavo Padovan
parent 459b086d87
commit 03c0c5f664
1 changed files with 5 additions and 0 deletions
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5
drivers/dma-buf/dma-fence.c
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@ -402,6 +402,11 @@ dma_fence_default_wait(struct dma_fence *fence, bool intr, signed long timeout)
}
}
if (!timeout) {
ret = 0;
goto out;
}
cb.base.func = dma_fence_default_wait_cb;
cb.task = current;
list_add(&cb.base.node, &fence->cb_list);