Date: Mon, 12 Mar 2001 11:02:01 -0800 (PST) From: John Baldwin <jhb@FreeBSD.org> To: Joseph Gleason <clash@tasam.com> Cc: freebsd-hackers@FreeBSD.org, Ian Campbell <ianc@ednet.co.uk>, Alfred Perlstein <bright@wintelcom.net> Subject: Re: Greater than 2GB per process Message-ID: <XFMail.010312110201.jhb@FreeBSD.org> In-Reply-To: <003701c0aaaf$a4566ce0$dc02010a@fireduck.com>
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On 12-Mar-01 Joseph Gleason wrote: > > ----- Original Message ----- > From: "Alfred Perlstein" <bright@wintelcom.net> > To: "Ian Campbell" <ianc@ednet.co.uk> > Cc: <freebsd-hackers@FreeBSD.ORG> > Sent: Sunday, March 11, 2001 23:41 > Subject: Re: Greater than 2GB per process > > >> * Ian Campbell <ianc@ednet.co.uk> [010311 16:14] wrote: >> > >> > Hello, >> > Could anybody advise me on the possiblity of having greater than >> > 2GB per process on FreeBSD. I have tried increasing the limit beyond > this >> > and the kernel compiles successfully - however libc causes every process >> > to segfault. I am assuming that just recompiling the C library wouldn't > do >> > the trick but perhaps someone could confirm this. >> >> It's not possible on the Intel archetecture with the current system, >> changing the current intel system to use > 2GB processes would cost too >> much in terms of performance (64 bit values on a 32 bit system). >> >> At least that's what i've been told. >> > > I know very little about how kernel or low level processor stuff works, but > shouldn't we be able to do a 4GB process on a 32-bit system? > The limitation of 2GB per process should only be an issue if there is some > need to use signed numbers, right? In theory, yes. In practice, the kernel and userland share the same memory area so that the kernel can more easily access user memory when handling syscalls, etc. Technically we could switch to using a separate virtual memory space for the kernel, but it would require work from someone very familiar with the vm system and the 386 side of vm. (Or someone willing to learn enough of it) We don't have very many such people unless you are volunteering. :) > Joe Gleason -- John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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