From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Thelen Subject: Re: [RFC v3 0/3] vmpressure_fd: Linux VM pressure notifications Date: Wed, 07 Nov 2012 09:20:35 -0800 Message-ID: References: <20121107105348.GA25549@lizard> <20121107112136.GA31715@shutemov.name> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: <20121107112136.GA31715-oKw7cIdHH8eLwutG50LtGA@public.gmane.org> (Kirill A. Shutemov's message of "Wed, 7 Nov 2012 13:21:36 +0200") Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Kirill A. Shutemov" Cc: Anton Vorontsov , Mel Gorman , Pekka Enberg , Leonid Moiseichuk , KOSAKI Motohiro , Minchan Kim , 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, linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-man@vger.kernel.org On Wed, Nov 07 2012, Kirill A. Shutemov wrote: > On Wed, Nov 07, 2012 at 02:53:49AM -0800, Anton Vorontsov wrote: >> Hi all, >> >> This is the third RFC. As suggested by Minchan Kim, the API is much >> simplified now (comparing to vmevent_fd): >> >> - As well as Minchan, KOSAKI Motohiro didn't like the timers, so the >> timers are gone now; >> - Pekka Enberg didn't like the complex attributes matching code, and so it >> is no longer there; >> - Nobody liked the raw vmstat attributes, and so they were eliminated too. >> >> But, conceptually, it is the exactly the same approach as in v2: three >> discrete levels of the pressure -- low, medium and oom. The levels are >> based on the reclaimer inefficiency index as proposed by Mel Gorman, but >> userland does not see the raw index values. The description why I moved >> away from reporting the raw 'reclaimer inefficiency index' can be found in >> v2: http://lkml.org/lkml/2012/10/22/177 >> >> While the new API is very simple, it is still extensible (i.e. versioned). > > Sorry, I didn't follow previous discussion on this, but could you > explain what's wrong with memory notifications from memcg? > As I can see you can get pretty similar functionality using memory > thresholds on the root cgroup. What's the point? Related question: are there plans to extend this system call to provide per-cgroup vm pressure notification? -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html