From owner-freebsd-hackers Sun Sep 30 21:41:24 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from elvis.mu.org (elvis.mu.org [216.33.66.196]) by hub.freebsd.org (Postfix) with ESMTP id 9C6F537B40C; Sun, 30 Sep 2001 21:41:19 -0700 (PDT) Received: by elvis.mu.org (Postfix, from userid 1192) id 71C8F81D01; Sun, 30 Sep 2001 23:41:14 -0500 (CDT) Date: Sun, 30 Sep 2001 23:41:14 -0500 From: Alfred Perlstein To: Greg Lehey Cc: Jos Backus , hackers@FreeBSD.ORG Subject: Re: VM: dynamic swap remapping (patch) Message-ID: <20010930234114.P59854@elvis.mu.org> References: <20010929232953.B341@eix.do-labs.spb.ru> <20010929175653.Z59854@elvis.mu.org> <20010930120328.A534@eix.do-labs.spb.ru> <20010930035529.G59854@elvis.mu.org> <20010930134437.B284@eix.do-labs.spb.ru> <20010930105509.B2220@lizzy.bugworks.com> <20010930142326.L59854@elvis.mu.org> <20010930123359.A7241@lizzy.bugworks.com> <20010930145558.M59854@elvis.mu.org> <20011001131951.M31215@wantadilla.lemis.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20011001131951.M31215@wantadilla.lemis.com>; from grog@FreeBSD.org on Mon, Oct 01, 2001 at 01:19:51PM +0930 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG * Greg Lehey [010930 22:49] wrote: > On Sunday, 30 September 2001 at 14:55:58 -0500, Alfred Perlstein wrote: > > * Jos Backus [010930 14:35] wrote: > >> On Sun, Sep 30, 2001 at 02:23:26PM -0500, Alfred Perlstein wrote: > >>> * Jos Backus [010930 12:55] wrote: > >>>> AIX has SIGDANGER. > >>> > >>> Anyone care to tell me how it works in AIX? If the interface is > >>> nice, cloning it would be kind of cool. > >> > >> I don't currently have access to an AIX system, but > >> > >> http://as400bks.rochester.ibm.com/doc_link/en_US/a_doc_lib/aixbman/admnconc/pag_space_under.htm > >> > >> has some (useful) info. > > > > It sure does! > > > > I think I'm going to make a proposal on -arch about this, to be > > perfectly honest, AIX has a good implementation, I haven't read it > > all yet, but it doesn't look like it gives the applications a > > notification when the danger is gone, we'll have to figure that out, > > or I'll have to read more into this. > > If it's any help, I have an AIX box here. It belongs to IBM, so I > have to respect security issues, but I'll do what I can. Well Joe seems to have provided a pretty interesting document on how it works in AIX, but I was wondering if they do anything wrt low/high watermarks like my idea. Basically you'd like to inform processes that the danger has been alliviated so that they can cautiously start accepting more work rather than freaking out and shutting out clients forever... This might lead to a situation where SIGDANGER starts getting sent informing that things are looking bleak, then processes start freeing resources, they get the second SIGDANGER to let them know that things are looking ok so they ramp up again and the cycle repeats, I guess that's not optimal, but I'd like FreeBSD to let processes know that things are looking better so they can go from "scrooge mode" to "thrifty mode". -- -Alfred Perlstein [alfred@freebsd.org] 'Instead of asking why a piece of software is using "1970s technology," start asking why software is ignoring 30 years of accumulated wisdom.' To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message