Date: Fri, 7 Feb 2003 20:51:45 -0800 From: Alfred Perlstein <bright@mu.org> To: Jake Burkholder <jake@locore.ca> Cc: Jeff Roberson <jroberson@chesapeake.net>, arch@FreeBSD.ORG Subject: Re: New kernel allocation API Message-ID: <20030208045145.GE88781@elvis.mu.org> In-Reply-To: <20030207234049.A32864@locore.ca> References: <20030208022722.GB88781@elvis.mu.org> <20030207221623.V72073-100000@mail.chesapeake.net> <20030208041659.GC88781@elvis.mu.org> <20030207234049.A32864@locore.ca>
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* Jake Burkholder <jake@locore.ca> [030207 20:38] wrote: > Apparently, On Fri, Feb 07, 2003 at 08:16:59PM -0800, > Alfred Perlstein said words to the effect of; > > > Doh, I guess I should be paying more attention, sorry for that. > > > > What advantage do you get from using direct mapped pages? Why not > > alias/map them into kmem map? I know you'd pay a penalty for the > > vm overhead, but you'd gain back the fixed array trick. I'm probably > > missing something? > > It lets you use the largest page size supported by the tlb (256 megs for > ia64 (!)), and it doesn't take a tlb shootdown to add or remove a mapping > because they never change. That makes sense, at first the idea of requiring free to take a size really seemed to suck, but it would be optional right? Other sections can still use jeff's lookup method when free is not passed a size right? This is somewhat premature as we should probably just convert over most of the fixed sized structures to use zones/slabs, but offering the "optimized" free sounds nice. If you guys have the time, go for it. :) -- -Alfred Perlstein [alfred@freebsd.org] 'Instead of asking why a piece of software is using "1970s technology," start asking why software is ignoring 30 years of accumulated wisdom.' To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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