On Fri, May 02, 2014 at 06:00:56PM -0400, Johannes Weiner wrote: > On Fri, May 02, 2014 at 06:49:30PM +0200, Michal Hocko wrote: > > On Fri 02-05-14 11:58:05, Johannes Weiner wrote: > > > This is not even guarantees anymore, but rather another reclaim > > > prioritization scheme with best-effort semantics. That went over > > > horribly with soft limits, and I don't want to repeat this. > > > > > > Overcommitting on guarantees makes no sense, and you even agree you > > > are not interested in it. We also agree that we can always add a knob > > > later on to change semantics when an actual usecase presents itself, > > > so why not start with the clear and simple semantics, and the simpler > > > implementation? > > > > So you are really preferring an OOM instead? That was the original > > implementation posted at the end of last year and some people > > had concerns about it. This is the primary reason I came up with a > > weaker version which fallbacks rather than OOM. > > I'll dig through the archives on this then, thanks. The most recent discussion on this I could find was between you and Greg, where the final outcome was (excerpt): --- From: Greg Thelen <gthelen@xxxxxxxxxx> To: Michal Hocko <mhocko@xxxxxxx> Cc: linux-mm@xxxxxxxxx, Johannes Weiner <hannes@xxxxxxxxxxx>, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>, LKML <linux-kernel@xxxxxxxxxxxxxxx>, Ying Han <yinghan@xxxxxxxxxx>, Hugh Dickins <hughd@xxxxxxxxxx>, Michel Lespinasse <walken@xxxxxxxxxx>, KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>, Tejun Heo <tj@xxxxxxxxxx> Subject: Re: [RFC 0/4] memcg: Low-limit reclaim References: <1386771355-21805-1-git-send-email-mhocko@xxxxxxx> <xr93sis6obb5.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxx> <20140130123044.GB13509@xxxxxxxxxxxxxx> <xr931tzphu50.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxx> <20140203144341.GI2495@xxxxxxxxxxxxxx> Date: Mon, 03 Feb 2014 17:33:13 -0800 Message-ID: <xr93zjm7br1i.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxx> List-ID: <linux-mm.kvack.org> On Mon, Feb 03 2014, Michal Hocko wrote: > On Thu 30-01-14 16:28:27, Greg Thelen wrote: >> But this soft_limit,priority extension can be added later. > > Yes, I would like to have the strong semantic first and then deal with a > weaker form. Either by a new limit or a flag. Sounds good. --- So I think everybody involved in the discussions so far are preferring a hard guarantee, and then later, if needed, to either add a knob to make it a soft guarantee or to actually implement a usable soft limit. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>