Hello, Paolo. On Fri, Apr 22, 2016 at 08:19:47PM +0200, Paolo Valente wrote: > > So, a kworker would jump through different workqueues and issue IOs > > for different writeback domains and the context can't be tied to the > > issuing task. The cgroup membership should be determined directly > > from the bio. > > Yes. My doubt arises from the fact that the only source of intense I/O > is the dd (I have executed it alone). In contrast, group changes occur > at a high frequency during all the execution of the dd. Apparently I > cannot see any other I/O induced by the dd. Journaling issues sync > requests. > > > cfq uses per-cgroup async queue. I'm not sure how this > > would map to bfq tho. > > It’s the same. But this is the part I’m checking.
Ah, right, I was confused. cic is always associated with the task and yes a writeback worker can trigger blkcg changed events frequently as it walks through different cgroups. Is this an issue? Thanks. -- tejun
