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 _______________________________________________ systemd-devel mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/systemd-devel
