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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/x86_64/mm.txt
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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1
2<previous description obsolete, deleted>
3
4Virtual memory map with 4 level page tables:
5
60000000000000000 - 00007fffffffffff (=47bits) user space, different per mm
7hole caused by [48:63] sign extension
8ffff800000000000 - ffff80ffffffffff (=40bits) guard hole
9ffff810000000000 - ffffc0ffffffffff (=46bits) direct mapping of phys. memory
10ffffc10000000000 - ffffc1ffffffffff (=40bits) hole
11ffffc20000000000 - ffffe1ffffffffff (=45bits) vmalloc/ioremap space
12... unused hole ...
13ffffffff80000000 - ffffffff82800000 (=40MB) kernel text mapping, from phys 0
14... unused hole ...
15ffffffff88000000 - fffffffffff00000 (=1919MB) module mapping space
16
17vmalloc space is lazily synchronized into the different PML4 pages of
18the processes using the page fault handler, with init_level4_pgt as
19reference.
20
21Current X86-64 implementations only support 40 bit of address space,
22but we support upto 46bits. This expands into MBZ space in the page tables.
23
24-Andi Kleen, Jul 2004