On Mon, 2015-03-02 at 10:09 +0100, Peter Zijlstra wrote: > On Thu, Feb 26, 2015 at 12:12:31PM -0500, Rik van Riel wrote: > > Subject: cpusets,isolcpus: add file to show isolated cpus in cpuset > > > > The previous patch makes it so the code skips over isolcpus when > > building scheduler load balancing domains. This makes it hard to > > see for a user which of the CPUs in a cpuset are participating in > > load balancing, and which ones are isolated cpus. > > > > Add a cpuset.isolcpus file with info on which cpus in a cpuset are > > isolated CPUs. > > > > This file is read-only for now. In the future we could extend things > > so isolcpus can be changed at run time, for the root (system wide) > > cpuset only. > > > > Acked-by: David Rientjes <rientjes@xxxxxxxxxx> > > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > > Cc: Clark Williams <williams@xxxxxxxxxx> > > Cc: Li Zefan <lizefan@xxxxxxxxxx> > > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > > Cc: Luiz Capitulino <lcapitulino@xxxxxxxxxx> > > Cc: David Rientjes <rientjes@xxxxxxxxxx> > > Cc: Mike Galbraith <umgwanakikbuti@xxxxxxxxx> > > Cc: cgroups@xxxxxxxxxxxxxxx > > Signed-off-by: Rik van Riel <riel@xxxxxxxxxx> > > So let me start off by saying I hate isolcpus ;-) > > Let me further state that I had hopes we could extend cpusets to > natively provide the functionality isolcpus has, and kill isolcpus. +1 That's where nohz_full goop belongs too. > The 'normal' way would be to create 2 cgroups with disjoint cpus, > disable sched_load_balance on root and one of the siblings, while moving > everything into the other group. That's what cset shield does, works fine. > The 'problem' is that we cannot move everything that is affected by > isolcpus, workqueues have grown a horrible 'new' interface outside of > the regular task interfaces and things like kthreadd are non-movable for > mostly good reasons. > > Furthermore it appears that software like system-disease and libvirt > hard assume they're lord and master of the cgroup hierarchy and do not > expect things like this. > > So while I mostly hate all of this it might be the best we can do :-( Hm, I'm now all system-disease-ified now (still hate the bloody thing), and have no problem isolating cpus via cpusets, modulo workqueues wanting a bat upside the head. -Mike -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
