Date: Thu, 29 Aug 2002 18:17:08 +0300 (EET DST) From: Aaro J Koskinen <akoskine@cc.helsinki.fi> To: <freebsd-hackers@freebsd.org> Subject: More dynamic KVA_SPACE Message-ID: <Pine.OSF.4.30.0208291600300.303-100000@sirppi.helsinki.fi>
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Hello all, I've been thinking what kind of modifications would it need to decide the KVA space size at the kernel boot time (maybe an argument to btext), instead of compile time. In theory I can't see any obstacles. Basically the approach would be simply the following: - The current KERNBASE would be moved upwards in the virtual memory, so that the kernel text/data/bss would be at the end of the kernel virtual memory. This area [KERNBASE, end] would be fixed at the compile time, and would be large enough to hold just the static segments (few MB, maybe). - All the remaining kernel VM would be below KERNBASE, and the lowest address of this area could be parametrized, and would mark the start of the KVM (the current VM_MIN_KERNEL_ADDRESS). - A lot of #define'd constants related to VM boundaries & PDE division would be based on variables initialized in the boot, also the interpretation of KERNBASE would change. Am I completely off the track? What are the main reasons behind the current KVM layout? A. -- Aaro Koskinen E-mail: aaro@iki.fi "I'm the ocean, I'm the giant undertow." http://www.iki.fi/aaro To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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