Date: Mon, 15 Jan 2001 16:43:08 -0500 (EST) From: Daniel Eischen <eischen@vigrid.com> To: John Baldwin <jhb@FreeBSD.org> Cc: "Justin T. Gibbs" <gibbs@scsiguy.com>, Bruce Evans <bde@zeta.org.au>, cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org, Wilko Bulte <wkb@freebie.demon.nl>, Poul-Henning Kamp <phk@critter.freebsd.dk>, Peter Wemm <peter@netplex.com.au> Subject: Re: cvs commit: src/sys/i386/conf GENERIC Message-ID: <Pine.SUN.3.91.1010115164043.17058B-100000@pcnet1.pcnet.com> In-Reply-To: <XFMail.010115133434.jhb@FreeBSD.org>
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On Mon, 15 Jan 2001, John Baldwin wrote: > > On 15-Jan-01 Justin T. Gibbs wrote: > >>See those 'cli' and 'popfl' instrucitons? Those are _privileged_. Userland > >>can't disable/enable interrupts, so we have to trap into the kernel to do > >>this > >>no matter what. > > > > All that is required in the userland implementation is the setting of a > > flag so the userland thread scheduler does not perform a thread switch. > > Having an interrupt fire does not have the same consequences on a userland > > program as it does for the kernel. > > Actually, the process needs to not be switched. This is part of KSE, so you > would have to set a kernel flag in the kse for this, but yes, that would work. > Granted, it pessimizes the non-i386 case, but not that badly. The kernel trap > to emulate only pessimizes the i386 case (though the 386 could do without extra > pessimizations, and it is a bigger pessimization.) I wouldn't want to set anything that tells the kernel not to switch the process (or KSE). That shouldn't be allowed from userland, at least without proper permissions. -- Dan Eischen To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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