[craigsmansion]

Ah yes, "cgroups", according to notable no-nonsense kernel hacker Al Viro:

"it's not just badly written kernel/cgroup.c - the interfaces on both sides (userland and the rest of kernel) are seriously misdesigned. As far as I'm concerned, configuring it out solves my problem nicely."

That was in 2011, so things might have improved. What remains however is that cgroups was added to the kernel, by Googlers, for easier maintenance, but with an implicit understanding that no sane person would actually make use of it to do something important.

... enter SystemD.

[menage]

It's true that a better userspace API for cgroups might have involved something more like ioctl(), rather than a filesystem with text-based control files. But people had been trying to get such APIs into the kernel for years with no success. Which is why we tried to piggyback on something existing.

Cpusets, which had already been accepted into the kernel a year or two previously, provided the basic userspace API for cgroups. It was just expanded to support control files for more resource types. (And multiple resource hierarchies, although that's gone in cgroups v2 I think).

[jeffbee]

The whole google is built on cgroups v1, which seems to stand as an existence proof that these interfaces are not useless.

[yjftsjthsd-h]

"bad design" and "useful" can be overlapping groups

[PaulDavisThe1st]

so when someone is using gmail on a macOS system, how are they using cgroups in any way? how is "the whole google" built on this? perhaps you means "google's web-facing servers using cgroups extensively" ?

[jeffbee]

That is a somewhat weird and dare I say pointless take. Thousands of machines are involved in serving every request from a web browser to gmail. Of those, only the web browser might not be in linux cgroups.