Re: [Linaro-mm-sig] [PATCH] dma-buf/sync-file: Avoid enable fence signaling if poll(.timeout=0)

Hi Chris,

2016-08-29 Chris Wilson chris@chris-wilson.co.uk:

If we being polled with a timeout of zero, a nonblocking busy query, we don't need to install any fence callbacks as we will not be waiting. As we only install the callback once, the overhead comes from the atomic bit test that also causes serialisation between threads.

Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Sumit Semwal sumit.semwal@linaro.org Cc: Gustavo Padovan gustavo@padovan.org Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org

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drivers/dma-buf/sync_file.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

Indeed, we can shortcut this.

Reviewed-by: Gustavo Padovan gustavo.padovan@collabora.co.uk

Gustavo