Hi Tejun, On Wed, Jun 05, 2019 at 06:53:19AM -0700, Tejun Heo wrote: > Hello, Daniel. > > On Wed, Jun 05, 2019 at 09:36:45AM -0400, Daniel Jordan wrote: > > My use case for this work is kernel multithreading, the series formerly known > > as ktask[2] that I'm now trying to combine with padata according to feedback > > from the last post. Helper threads in a multithreaded job may consume lots of > > resources that aren't properly accounted to the cgroup of the task that started > > the job. > > Can you please go into more details on the use cases? If I remember correctly, the original Bandan's work was about using workqueues instead of kthreads in vhost. > For memory and io, we're generally going for remote charging, where a > kthread explicitly says who the specific io or allocation is for, > combined with selective back-charging, where the resource is charged > and consumed unconditionally even if that would put the usage above > the current limits temporarily. From what I've been seeing recently, > combination of the two give us really good control quality without > being too invasive across the stack. > > CPU doesn't have a backcharging mechanism yet and depending on the use > case, we *might* need to put kthreads in different cgroups. However, > such use cases might not be that abundant and there may be gotaches > which require them to be force-executed and back-charged (e.g. fs > compression from global reclaim). > > Thanks. > > -- > tejun > -- Sincerely yours, Mike.
