On Mon, Dec 26, 2016 at 02:01:31PM +0100, Heiner Kallweit wrote: > Am 02.08.2016 um 07:44 schrieb Heiner Kallweit: > > I think we can get rid of the spinlock protecting the kthread from being > > interrupted by a wakeup in certain parts. > > Even with the current implementation of the kthread the only lost wakeup > > scenario could happen if the wakeup occurs between the kfifo_len check > > and setting the state to TASK_INTERRUPTIBLE. > > > > In the changed version we could lose a wakeup if it occurs between > > processing the fifo content and setting the state to TASK_INTERRUPTIBLE. > > This scenario is covered by an additional check for available events in > > the fifo and setting the state to TASK_RUNNING in this case. > > > > In addition the changed version flushes the kfifo before ending > > when the kthread is stopped. > > > > With this patch we gain: > > - Get rid of the spinlock > > - Simplify code > > - Don't grep / release the mutex for each individual event but just once > > for the complete fifo content. This reduces overhead if a driver e.g. > > triggers processing after writing the content of a hw fifo to the kfifo. > > > > Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx> > > Sean added a review comment and his "Tested-by" a month ago. > Anything else missing before it can be applied? I have it applied here: https://git.linuxtv.org/syoung/media_tree.git/log/?h=for-v4.11a I'll ask Mauro to pull that tree soon, now that 4.10-rc1 has been merged. I need to do some testing. Sean -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
