From 03c0c5f6641533f5fc14bf4e76d2304197402552 Mon Sep 17 00:00:00 2001 From: Andres Rodriguez Date: Wed, 26 Apr 2017 10:46:20 -0400 Subject: [PATCH] dma-buf: avoid scheduling on fence status query v2 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Christian König Signed-off-by: Gustavo Padovan Link: http://patchwork.freedesktop.org/patch/msgid/20170426144620.3560-1-andresx7@gmail.com --- drivers/dma-buf/dma-fence.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index 0918d3f003d6..57da14c15987 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -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); -- 2.20.1