Messages in this thread | | | Date | Tue, 26 Jul 2011 09:25:31 +0800 | From | Li Zefan <> | Subject | Re: [PATCH 7/7] cgroups: Add a max number of tasks subsystem |
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Paul Menage wrote: > On Mon, Jul 11, 2011 at 7:15 AM, Frederic Weisbecker <fweisbec@gmail.com> wrote: >> /* */ >> + >> +#ifdef CONFIG_CGROUP_MAX_TASKS >> +SUBSYS(max_tasks) >> +#endif > > I think I'd be inclined to make the naming slightly (IMO) cleaner: > call the subsystem 'tasks' and the files 'limit' and 'count' (or maybe > 'usage' to be more in line with memcg). >> >> +config CGROUP_MAX_TASKS >> + bool "Control max number of tasks in a cgroup" >> + depends on RESOURCE_COUNTERS >> + help >> + This option let the user to set up an upper bound allowed number >> + of tasks. >> + > > Needs to depend on CGROUPS too? >
it's done implicitly, because it's inside "menuconfig CGROUPS".
>> + >> + >> +struct task_counter { >> + struct res_counter res; >> + struct cgroup_subsys_state css; >> +}; > > All other CSS structures put the "css" field as the first thing in the > structure. Not sure that anything relies on that, but consistency
no as far as I know, and that's a bad thing.
> can't hurt and it probably makes the code fractionally smaller since > the translation between CSS and task_counter becomes a no-op. > >> +static void task_counter_exit(struct cgroup_subsys *ss, struct cgroup *cgrp, >> + struct cgroup *old_cgrp, struct task_struct *task) >> +{ >> + struct task_counter *cnt = cgroup_task_counter(old_cgrp); >> + >> + if (cnt != &root_counter) >> + res_counter_uncharge_until(&cnt->res, &root_counter.res, 1); >> +} > > Do we even need the root_counter to be exposed in any way? Why not > make children of the root cgroup just have a NULL parent res_counter? > > You'll still need a task_counter object so that the cgroups framework > has a CSS object for cgroups housekeeping, but I don't think it needs > to actually be used for anything. > > Paul >
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