From: Andi Kleen Date: Sat, 5 Nov 2005 16:25:54 +0000 (+0100) Subject: [PATCH] x86_64: Some clarifications for Documention/x86_64/mm.txt X-Git-Tag: v2.6.15-rc2~95^2~25 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8315eca25583c369e28f48909d3341dc21d6214d;p=linux-2.6 [PATCH] x86_64: Some clarifications for Documention/x86_64/mm.txt I got some questions on this, so just fix up the documentation. Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- diff --git a/Documentation/x86_64/mm.txt b/Documentation/x86_64/mm.txt index 662b73971a..133561b9cb 100644 --- a/Documentation/x86_64/mm.txt +++ b/Documentation/x86_64/mm.txt @@ -6,7 +6,7 @@ Virtual memory map with 4 level page tables: 0000000000000000 - 00007fffffffffff (=47bits) user space, different per mm hole caused by [48:63] sign extension ffff800000000000 - ffff80ffffffffff (=40bits) guard hole -ffff810000000000 - ffffc0ffffffffff (=46bits) direct mapping of phys. memory +ffff810000000000 - ffffc0ffffffffff (=46bits) direct mapping of all phys. memory ffffc10000000000 - ffffc1ffffffffff (=40bits) hole ffffc20000000000 - ffffe1ffffffffff (=45bits) vmalloc/ioremap space ... unused hole ... @@ -14,6 +14,10 @@ ffffffff80000000 - ffffffff82800000 (=40MB) kernel text mapping, from phys 0 ... unused hole ... ffffffff88000000 - fffffffffff00000 (=1919MB) module mapping space +The direct mapping covers all memory in the system upto the highest +memory address (this means in some cases it can also include PCI memory +holes) + vmalloc space is lazily synchronized into the different PML4 pages of the processes using the page fault handler, with init_level4_pgt as reference.