On Tue, May 11, 2010 at 12:49:46PM +0200, Julien Cristau wrote: > On Tue, May 11, 2010 at 12:37:56 +0200, Julian Andres Klode wrote: > > > On Sun, May 09, 2010 at 05:25:16PM +0200, Tollef Fog Heen wrote: > > > I am so far just testing on a singe machine, but it's my firm belief > > > that it's possible to have a fully functional systemd in squeeze. > > > > Only if #579755 is solved. While testing systemd on Debian, I found > > out that the option CONFIG_CGROUP_DEBUG is disabled in our kernel, > > but it is needed for systemd to work. > > > config CGROUP_DEBUG > bool "Example debug cgroup subsystem" > depends on CGROUPS > default n > help > This option enables a simple cgroup subsystem that > exports useful debugging information about the cgroups > framework. > > Say N if unsure. > > Is it really a good idea to have init depend on such an option? > (It's also disabled in all defconfigs.) Here's what I heard from Kay Sievers: Apr 30 16:13:27 <juliank> kay: Is there a way to get it working without this option? Apr 30 16:13:58 <kay> no, no chance Apr 30 16:14:18 <kay> it's one of the building blocks to track/babysit processes Apr 30 16:17:24 <kay> it will not be "debug" some day, but always required, yes Apr 30 16:17:57 <kay> there is otherwise no way to reliably kill a service, you need a simple "container" to kill Apr 30 16:18:17 <kay> otherwise processes can fork faster than you can kill them Apr 30 16:18:38 <kay> cgroups provide a race free way to kill an entire group of processes Apr 30 16:19:13 <kay> and they can also tell you that all processes of a service died -> empty group Apr 30 16:20:30 <juliank> kay: Does CONFIG_CGROUP_DEBUG have any impact on performance? Apr 30 16:20:48 <kay> it should not be noticeable Apr 30 16:21:03 <kay> only if you actually use them, and even then they are very cheap Apr 30 16:21:20 <kay> it's not much more than a tag sticked to a process Apr 30 16:21:38 <kay> and a way to handle the tagged things then ... -- Julian Andres Klode - Debian Developer, Ubuntu Member See http://wiki.debian.org/JulianAndresKlode and http://jak-linux.org/.
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