Date: Thu, 21 Jan 1999 21:37:34 -0800 From: Mike Smith <mike@smith.net.au> To: "Robert V. Baron" <rvb@cs.cmu.edu> Cc: Mike Smith <mike@smith.net.au>, Geoff Buckingham <geoffb@demon.net>, freebsd-current@FreeBSD.ORG Subject: Re: KVA/KVM shortages Message-ID: <199901220537.VAA13835@dingo.cdrom.com> In-Reply-To: Your message of "21 Jan 1999 22:05:23 EST." <yzsemoouhvw.fsf@sicily.odyssey.cs.cmu.edu>
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> Mike Smith <mike@smith.net.au> writes: > > > I just committed a tweak that allows you to say: > > > > set kern.vm.kmem.size=<value> > > > > at the loader prompt or in /boot/loader.rc to override the default > > VM_KMEM_SIZE value. > > > > If anyone has any more of these tunables that can easily be enhanced > > like this, please let me know. > > > How about all the parameters that are assigned in param.c? Why not > make them all tweakable in the loader.rc, rather than having to patch > the kernel. Because they're not all used in fashions that either make tuning them really desirable, or easy. I looked at all of them and decided that most weren't actually really candidates for that sort of hackery. > Actually, thinking about this a little more ... > The loader knows where all symbols are in memory. Why not a general > mechanism to let you reassign the value of any "variable" used in > the kernel or in a module. I presume that the loader allocates bss > for the kernel and each module as it loads it. So I presume I can > assign a value to a variable that would ordinarily take on a 0 > value, too. Because most of them are initialised at runtime from preprocessor defines, so tweaking their initial values wouldn't save anything (you'd have to hack the code anyway to have it not override a non-zero initial value). -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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