> > [snip] > > > > list_lock does not appear to be a good solution for this, since it is > > currently an IRQ-safe spinlock on the device. Using it would cause > > _read() to have unnecessary lock contention if the device is opened > > and read simultaneously from multiple fds, and every loop iteration would > > need to acquire the spinlock / disable interrupts at least once. > > We could make the spinlock per struct file *, which'd remove the > contention bottleneck when the same device is accessed from through > multiple fds, but still maintain the correctness (as the list itself is a > per-fd thing anyway). > > Probably introducing new spinlock would make more sense, as list_lock is > currently being used mostly to protect accessing of the dev->list linked > list. I've got a patch I'm testing that follows Dmitry's suggestion to add a per-struct file spinlock and change dev->list to use RCU. Thanks, - Gary -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
