]> git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/commitdiff
dma-buf: avoid scheduling on fence status query v2
authorAndres Rodriguez <andresx7@gmail.com>
Wed, 16 Aug 2017 11:59:00 +0000 (13:59 +0200)
committerKleber Sacilotto de Souza <kleber.souza@canonical.com>
Thu, 24 Aug 2017 09:42:00 +0000 (11:42 +0200)
BugLink: http://bugs.launchpad.net/bugs/1711096
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
(cherry picked from commit 03c0c5f6641533f5fc14bf4e76d2304197402552)
Signed-off-by: Alberto Milone <alberto.milone@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
drivers/dma-buf/dma-fence.c

index 0212af7997d9fa2177b39d05b675ad047743f35f..96b3221433f0d0b52c13c75b95ebea28dd548334 100644 (file)
@@ -373,6 +373,11 @@ 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);