On Tue 13-05-14 14:39:53, Andrew Morton wrote: > On Tue, 13 May 2014 17:29:16 +0200 Michal Hocko <mho...@suse.cz> wrote: > > > 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 > > because I do not expect most users will use sane_behavior cgroups mode > > very soon. > > Anyway 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 because 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. > > > > ... > > > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -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...@kvack.org\n"); > > return mem_cgroup_force_empty(memcg); > > } > > > > Do we really want to spam the poor user each and every time they use > this? Using pr_info_once() is kinder and gentler?
We do not catch all potential callers but it is true that some configurations might have thousands of cgroups and the notify_on_release handler will spam the log. > From: Andrew Morton <a...@linux-foundation.org> > Subject: memcg-deprecate-memoryforce_empty-knob-fix > > - s/pr_info/pr_info_once/ > - fix garbled printk text > > Cc: Johannes Weiner <han...@cmpxchg.org> > Cc: Michal Hocko <mho...@suse.cz> > Signed-off-by: Andrew Morton <a...@linux-foundation.org> Acked-by: Michal Hocko <mho...@suse.cz> > --- > > Documentation/cgroups/memory.txt | 2 +- > mm/memcontrol.c | 8 ++++---- > 2 files changed, 5 insertions(+), 5 deletions(-) > > diff -puN > Documentation/cgroups/memory.txt~memcg-deprecate-memoryforce_empty-knob-fix > Documentation/cgroups/memory.txt > --- > a/Documentation/cgroups/memory.txt~memcg-deprecate-memoryforce_empty-knob-fix > +++ a/Documentation/cgroups/memory.txt > @@ -482,7 +482,7 @@ About use_hierarchy, see Section 6. > memory.kmem.usage_in_bytes == memory.usage_in_bytes. > > Please note that this knob is considered deprecated and will be removed > - in future. > + in the future. > > About use_hierarchy, see Section 6. > > diff -puN mm/memcontrol.c~memcg-deprecate-memoryforce_empty-knob-fix > mm/memcontrol.c > --- a/mm/memcontrol.c~memcg-deprecate-memoryforce_empty-knob-fix > +++ a/mm/memcontrol.c > @@ -4799,10 +4799,10 @@ static int mem_cgroup_force_empty_write( > > 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...@kvack.org\n"); > + pr_info_once("%s (%d): memory.force_empty is deprecated and will be " > + "removed. Let us know if it is needed in your usecase at " > + "linux...@kvack.org\n", > + current->comm, task_pid_nr(current)); > return mem_cgroup_force_empty(memcg); > } > > _ > -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/