From: Rik van Riel <riel@conectiva.com.br> To: Alfred Perlstein <bright@mu.org> Cc: Vladimir Dozen <vladimir-dozen@mail.ru>, Matt Dillon <dillon@earth.backplane.com>, Wilko Bulte <wkb@freebie.xs4all.nl>, <hackers@FreeBSD.ORG> Subject: Re: VM: dynamic swap remapping (patch) Message-ID: <Pine.LNX.4.33L.0109300514360.19147-100000@imladris.rielhome.conectiva> In-Reply-To: <20010929175653.Z59854@elvis.mu.org>
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On Sat, 29 Sep 2001, Alfred Perlstein wrote: > * Vladimir Dozen <vladimir-dozen@mail.ru> [010929 14:38] wrote: > > > P.S. Anyway, I do NOT insist my solution is better, and even that it > > is good for anything at all. It was fun for me to hack in BSD kernel, > > and it was interesting challenge, and I feel need to share results > > with others. At worst, I will recommend our customer to setup > > processing farm under FreeBSD with applied patch. > > I'm really impressed with the work you put into this, but it seems > that you've tried to tackle two problems at the same time, Indeed, the whole idea of swapping tasks to the filesystem in nice, but having the task do this all by itself isn't a good option for many people... > My suggestion, (but not my final say, i'm still open to ideas): > > Implement a memory status signal to notify processes of changes > in the relative amount of system memory. > > When memory reaches a low or high watermark, the signal is > broadcast to all running processes. > > The default disposition will be to ignore the signal. > > The signal will be named SIGMEMINFO. (SIGXfoo means > 'process has exceeded resource foo') That'd be SIGDANGER, right ? > b) do the following enhancement: > > Provide a system whereby you can swap to the filesystem without > additional upcalls/syscalls from userspace, basically, provide > some means of paging to the filesystem automatically. Sounds like a winner, when swap runs out a process gets suspended onto the filesystem automatically and SIGDANGER is sent out to give others a chance to clean themselves up. If enough space is freed, the suspended process can get back into the system. This should also preserve leaky applications while at the same time leaving the system intact... regards, Rik -- IA64: a worthy successor to i860. http://www.surriel.com/ http://distro.conectiva.com/ Send all your spam to aardvark@nl.linux.org (spam digging piggy) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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