Understood. Thank you for the explanation. I'm not familiar with the cgroup rework being done so I don't have any ideas or opinion on that at the moment.
I was not aware of %c. It sounds like that might be a reasonable and simple workaround for now. thanks On Tue, Dec 10, 2013 at 9:24 AM, Lennart Poettering <[email protected]>wrote: > On Mon, 09.12.13 10:31, Joe Miller ([email protected]) wrote: > > > It appears that the .slice changed described here[1] removed all ability > to > > set low-level cgroups settings, is that correct? > > Yes, that is correct. With the new code only attributes that systemd > understands can be set, nothing else. > > > For cgroup attributes that systemd does not natively support > > (example: cpu.cfs_period_us and cpu.cfs_quota_us) it was previously > > possible to set these > > > > 1. via unit files: ControlGroupAttribute=cpu.cfs_period_us 500 > > 2. or at runtime: systemctl --runtime set-cgroup-attr thing.service > > cpu.cfs_period_us 500 > > > > I find the ability to set cgroup attrs not supported natively by systemd > > useful, will this be added back to systemd or will systemd support all > > cgroup attributes? > > The problem with supporting these generic attributes is that they all > have very different semantics how they can be reset and what writing to > them actually does (some overwrite previous settings, others are lists > that the new data you write is appended to, even others work more like a > dictionary). Also, a big chunk of them are going to go away with Tejun's > "sane behaviour" cgroup rework. > > We are happy to support more options high-level in systemd, however, > there needs to be a clear perspective that they are options that are > going to stay. The last time we discussed the cfs attributes in > particular Tejun indicated they wouldn't stay the way they are. > > Now, if there at least is a clear perspective how they are going to look > like in future in the kernel, then we can add support for them now > already and add a bit of compat code that tries to translate them to the > old cgroup kernel api, but I am not sure whether that is possible for > the cfs attributes. > > A dirty work-around for the time being is to simply set these properties > via a shell fragment. You can use the "%c" specifier which will tell you > the cgroup path of a service, use that in some ExecStartPre= script that > initializes these for you. > > If you'd like to see proper support for this stuff (which I certainly > want), then we need to discuss with Tejun how we can expose these props > already now. > > Lennart > > -- > Lennart Poettering, Red Hat >
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