Date: Fri, 22 Jan 1999 18:54:44 -0500 (EST) From: "John S. Dyson" <dyson@iquest.net> To: dufault@hda.com (Peter Dufault) Cc: dillon@apollo.backplane.com, dyson@iquest.net, hackers@FreeBSD.ORG Subject: Re: Error in vm_fault change Message-ID: <199901222354.SAA36875@y.dyson.net> In-Reply-To: <199901222331.SAA22095@hda.hda.com> from Peter Dufault at "Jan 22, 99 06:31:58 pm"
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Peter Dufault said: > > Basically what it comes down to is that I do not think it is appropriate > > for there to be hacks all around the kernel to arbitrarily block processes > > in low memory situations. At the very worst, those same 'blockages' could > > be implemented in one place - the memory allocator, and nowhere else. But > > we can do much better. > > No one will argue with that. While moving things to one place you > should define requirements also so that you can see that changes > don't break anything. > > As someone interested in realtime I'll toss two requirements at > you: you should be able to behave as if you have less physical > memory than you do to permit locked in regions (should be easy), > and your algorithms should be able to define a maximum amount of > time (for a specific configuration) that it will take to reduce > that number, that is, if I give you five seconds warning can you > guarantee me more two more MB memory? For the second requirement > don't concern yourself with obvious Unixy issues or anything outside > the VM subsystem, only that the algorithms in your now well contained > subsystem are determinate. > Your comments about "goals" are correct. The obsolete notion of priority is specious. -- John | Never try to teach a pig to sing, dyson@iquest.net | it makes one look stupid jdyson@nc.com | and it irritates the pig. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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