From: Greg Kroah-Hartman <gre...@linuxfoundation.org> Date: Wed, 12 Feb 2014 08:56:30 -0800
> On Wed, Feb 12, 2014 at 06:38:21PM +0200, Michael S. Tsirkin wrote: >> It is sometimes useful to get the value of the reference count after >> decrement. >> For example, vhost wants to execute some periodic cleanup operations >> once number of references drops below a specific value, before it >> reaches zero (for efficiency). > > You should never care about what the value of the kref is, if you are > using it correctly :) It isn't being used to determine when to destroy things. They use it to as a heuristic of when to trigger polling. Each ubuf attached gets a kref to the higher level virtio_net buffer holding object, they want to trigger polling when that reference drops to 1 or lower. Right now they are reading the atomic refcount directly, which I think is much worse than this helper. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
