On Mon, May 12, 2014 at 05:34:58PM +0200, Michal Hocko wrote: > On Mon 12-05-14 11:25:07, Tejun Heo wrote: > > On Mon, May 12, 2014 at 05:20:15PM +0200, Michal Hocko wrote: > > > On Mon 12-05-14 11:00:14, Tejun Heo wrote: > > > > On Mon, May 12, 2014 at 04:58:03PM +0200, Michal Hocko wrote: > > > > > @@ -4793,6 +4793,10 @@ static int mem_cgroup_force_empty_write(struct cgroup_subsys_state *css, > > > > > > > > > > if (mem_cgroup_is_root(memcg)) > > > > > return -EINVAL; > > > > > + pr_info("%s (%d): memory.force_empty is deprecated and will be removed.", > > > > > + current->comm, task_pid_nr(current)); > > > > > + pr_cont(" Let us know if you know if it needed in your usecase at"); > > > > > + pr_cont(" linux-mm@xxxxxxxxx\n"); > > > > > return mem_cgroup_force_empty(memcg); > > > > > > > > It probably would be way easier to just mark the knob with > > > > CFTYPE_INSANE. > > > > > > That would prevent from creating the file, right? I do not mind that but > > > I would like to see people complaining before. > > > > Oh sure, if you wanna see people complaining before the roll out of > > unified hierarchy, but let's make sure it's also marked with > > CFTYPE_INSANE. It's easy to remove the flag afterwards. The other > > way isn't, so... > --- > >From 6f2a33df7750f0794b03f7a85aba02a4e631f2a0 Mon Sep 17 00:00:00 2001 > From: Michal Hocko <mhocko@xxxxxxx> > Date: Mon, 12 May 2014 16:20:46 +0200 > Subject: [PATCH] memcg: deprecate memory.force_empty knob > > force_empty has been introduced primarily to drop memory before it gets > reparented on the group removal. This alone doesn't sound fully > justified because reparented pages which are not in use can be reclaimed > also later when there is a memory pressure on the parent level. > > Mark the knob CFTYPE_INSANE which tells the cgroup core that it > shouldn't create the knob with the experimental sane_behavior. Other > users will get informed about the deprecation and asked to tell us more. > But I expect that most users will be simply cgroup remove handlers > which do that since ever without having any good reason for it. > > If somebody really cares and the reparented pages, which would be dropped > otherwise, push out more important ones then we should fix the > reparenting code and put pages to the tail. > > Signed-off-by: Michal Hocko <mhocko@xxxxxxx> I'm skeptical the printk will do anything useful, but you marked the knob insane and that's the most important change. Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html