I/O performance is the bottleneck in many systems, from phones to servers. Knowing which request to schedule at any moment is crucial to systems that support interactive latencies and high throughput. When you're watching a video on your desktop, you don't want it to skip when you build a kernel. To address this in our environment Google has now deployed the blk-cgroup code worldwide, and I'd like to share some of our experiences. We've made modifications for our purposes, and are in the process of proposing those upstream: - Page tracking for buffered writes - Fairness-preserving preemption across cgroups There is further work to do along the lines of fine-grained accounting and isolation. For example, many file servers in a Google cluster will do IO on behalf of hundreds, even thousands of clients. Each client has different service requirements, and it's inefficient to map them to (cgroup, task) pairs. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
