From owner-freebsd-alpha Wed Aug 22 7:56:59 2001 Delivered-To: freebsd-alpha@freebsd.org Received: from earth.backplane.com (earth-nat-cw.backplane.com [208.161.114.67]) by hub.freebsd.org (Postfix) with ESMTP id 1DB1837B418; Wed, 22 Aug 2001 07:56:43 -0700 (PDT) (envelope-from dillon@earth.backplane.com) Received: (from dillon@localhost) by earth.backplane.com (8.11.4/8.11.2) id f7MEufD74609; Wed, 22 Aug 2001 07:56:41 -0700 (PDT) (envelope-from dillon) Date: Wed, 22 Aug 2001 07:56:41 -0700 (PDT) From: Matt Dillon Message-Id: <200108221456.f7MEufD74609@earth.backplane.com> To: Terry Lambert Cc: Jake Burkholder , John Baldwin , freebsd-smp@FreeBSD.ORG, freebsd-alpha@FreeBSD.ORG Subject: Re: Preliminary proposed rollup of kernel submap initialization code References: <200108210157.f7L1vAh10384@k7.locore.ca> <200108211736.f7LHaoC64628@earth.backplane.com> <3B83623D.9DC45B93@mindspring.com> Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org :Then you pass it's address in... : :> +void :> +vm_ksubmap_init(struct kva_md_info *kmi) :> +{ : :And then use much more expensive pointer arithmatic... : :> + buffer_map = kmem_suballoc(clean_map, &kmi->buffer_sva, :> + &kmi->buffer_eva, (nbuf*BKVASIZE)); : :I understand that this is called once, but doesn't this :really obfuscate things? : :-- Terry I don't follow. The argument passing and pointer arithmatic is not expensive at all - in fact, it is less expensive then the original MD code if you look at the assembly output! And who really gives a damn about a few nanoseconds during boot anyway? kmi is static in the MD sections because it allows the kernel to compile for all platforms without us having to 'fix' all platforms all at once. One could also argue that the mainline kernel code has no direct need to know about the contents of kmi but that wasn't the main reason for doing it that way. -Matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message