Messages in this thread | | | Date | Thu, 23 Jun 2011 15:38:58 +0200 | From | Frederic Weisbecker <> | Subject | Re: [RFC PATCH 1/4] cgroups: Allow a cgroup subsys to reject a fork |
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On Tue, Jun 21, 2011 at 10:39:04AM -0700, Paul Menage wrote: > On Sun, Jun 19, 2011 at 4:51 PM, Frederic Weisbecker <fweisbec@gmail.com> wrote: > > Make the cgroup subsystem fork callback return a value > > so that subsystems are able to accept or reject a fork > > completion with a custom error value. > > This is unnecessary complexity in the cgroup subsystem (and seems to > miss cleanup for subsystems that have previously had their fork() > method return success).
No it seems only the freezer subsystem had this fork callback implemented. But indeed it adds complexity because if a subsystem can cancel a fork, then previous subsystems that called ->fork() would need to have a kind cancel_fork() callback to call.
I haven't looked very deep but the freezer doesn't seem to need any rollback. Future subsystems using the fork() callback may need it though.
> If you want a subsystem to be able to reject a fork, I think it's > better to have that subsystem be called explicitly from do_fork(), and > keep that logic out of cgroups.
Ok I can do that.
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