From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anton Vorontsov Subject: Re: [PATCH v2] memcg: Add memory.pressure_level events Date: Thu, 21 Feb 2013 15:04:26 -0800 Message-ID: <20130221230425.GA22792@lizard.fhda.edu> References: <20130219044012.GA23356@lizard.sbx00618.mountca.wayport.net> <20130220001743.GE16950@blaptop> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Tejun Heo Cc: Minchan Kim , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, David Rientjes , Pekka Enberg , Mel Gorman , Glauber Costa , Michal Hocko , "Kirill A. Shutemov" , Kamezawa Hiroyuki , Luiz Capitulino , Andrew Morton , Greg Thelen , Leonid Moiseichuk , KOSAKI Motohiro , Bartlomiej Zolnierkiewicz , John Stultz , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linaro-kernel-cunTk1MwBs8s++Sfvej+rw@public.gmane.org, patches-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, kernel-team-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org On Tue, Feb 19, 2013 at 04:21:28PM -0800, Tejun Heo wrote: > On Tue, Feb 19, 2013 at 4:17 PM, Minchan Kim wrote: > > Should we really enable memcg for just pressure notificaion in embedded side? > > I didn't check the size(cgroup + memcg) and performance penalty but I don't want > > to add unnecessary overhead if it is possible. > > Do you have a plan to support it via global knob(ie, /proc/mempressure), NOT memcg? > > That should be handled by mempressure at the root cgroup. If that adds > significant amount of overhead code or memory-wise, we just need to > fix root cgroup handling in memcg. No reason to further complicate the > interface which already is pretty complex. For what it worth, I agree here. Even if we decide to make another interface to vmpressure (which, say, would not require memcg), then it is better to keep the API the same: eventfd + control file. That way, API/ABI-wise there will be no differnce between memcg and non-memcg kernels, which is cool. Thanks, Anton