| Message ID | 20160829181613.30722-1-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 > --- > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Chris, On 29 August 2016 at 23:56, Gustavo Padovan <gustavo@padovan.org> wrote: > 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 >> --- >> 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 Thanks; pushed to drm-misc. Best, Sumit. -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c index 486d29c1a830..abb5fdab75fd 100644 --- a/drivers/dma-buf/sync_file.c +++ b/drivers/dma-buf/sync_file.c @@ -306,7 +306,8 @@ static unsigned int sync_file_poll(struct file *file, poll_table *wait) poll_wait(file, &sync_file->wq, wait); - if (!test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) { + if (!poll_does_not_wait(wait) && + !test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) { if (fence_add_callback(sync_file->fence, &sync_file->cb, fence_check_cb_func) < 0) wake_up_all(&sync_file->wq);
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 --- drivers/dma-buf/sync_file.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)