"Ronald G. Minnich" wrote: > On Thu, 5 Dec 2002, David Schultz wrote: > > > Linux used to do that, but AFAIK it doesn't anymore. > > Linux puts kvm at 0xc0000000, kernel at physical 0x100000, etc. There > was a time when you could address all of physical memory just by > direct-mapping the PTEs, since base of 0xc0000000 means KVM space > of 0x40000000. > > Those days are gone.
Sort-of. They now use a milti-tiered memory pool system. The first block is direct mapped in using 4MB pages. That works out to something like 930MB or so. The balance (they have a 1GB KVA space too) is pageable to allow the kernel to access memory outside of the first 930MB (or whatever the exact amount is). What linux does that I find interesting is that they agressively *move* user pages in order to get best use of that 930MB pool. Cheers, -Peter -- Peter Wemm - [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED] "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
