|From:||Lennart Poettering <mzxreary-AT-0pointer.de>|
|To:||Dhaval Giani <dhaval.giani-AT-gmail.com>|
|Subject:||Re: [RFC/RFT PATCH v3] sched: automated per tty task groups|
|Date:||Tue, 16 Nov 2010 18:03:12 +0100|
|Cc:||Peter Zijlstra <a.p.zijlstra-AT-chello.nl>, Mike Galbraith <efault-AT-gmx.de>, Vivek Goyal <vgoyal-AT-redhat.com>, Oleg Nesterov <oleg-AT-redhat.com>, Linus Torvalds <torvalds-AT-linux-foundation.org>, Markus Trippelsdorf <markus-AT-trippelsdorf.de>, Mathieu Desnoyers <mathieu.desnoyers-AT-efficios.com>, Ingo Molnar <mingo-AT-elte.hu>, LKML <linux-kernel-AT-vger.kernel.org>, Balbir Singh <balbir-AT-linux.vnet.ibm.com>|
On Tue, 16.11.10 15:47, Dhaval Giani (email@example.com) wrote: > > On Tue, Nov 16, 2010 at 3:11 PM, Peter Zijlstra <firstname.lastname@example.org> wrote: > > On Tue, 2010-11-16 at 07:02 -0700, Mike Galbraith wrote: > >> While you can identify firefox etc, > >> it's not being done, and requires identifying every application. Heck, > >> cgroups is built in, but userspace doesn't even mount. Nothing but > >> nothing uses cgroups. > > > > The yet another init rewrite called systemd is supposedly cgroup happy.. > > No idea if its going to be useful though, I doubt its going to have an > > effect on me launching a konsole or the like, or screen creating a bunch > > of ttys. > > systemd uses cgroups only for process tracking. No resource > management. Though afaik, Lennart has some plans of doing resource > management using systemd. I wonder how autogroups will interact with > systemd in that case. systemd already creates a named cgroup for each user who logs in and each session inside it. That's implemented via pam_systemd, which is enabled in all distros doing systemd. We create those groups right now only in the named "systemd" hierarchy, but iiuc then simply doing the same in the "cpu" hierarchy would have the exact same behaviour as this patch, but actually is based on a sane definition of what a session is. Binding something like this to TTYs is just backwards. No graphical session has a TTY attached anymore. And there might be multiple TTYs used in the same session. I really wonder why logic like this should live in kernel space at all, since a) the kernel has no real notion of a session, except audit and b) this is policy and as soon as people have this kind of group then they probably want other kind of autogrouping as well for the other controllers, which hence means userspace is a better, and configurable place for this. Lennart -- Lennart Poettering - Red Hat, Inc.
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