x86: Lift restriction on the location of FIX_BTMAP_*
authorJan Beulich <JBeulich@novell.com>
Fri, 18 Dec 2009 16:05:51 +0000 (16:05 +0000)
committerIngo Molnar <mingo@elte.hu>
Wed, 30 Dec 2009 10:57:30 +0000 (11:57 +0100)
commit499a5f1efa0b0ac56ec5d060412aed84ae68e63e
tree4e6bd3e2ed34b4b0736d89203e8f6212106a1f4f
parent39d997b514e12d5aff0dca206eb8996b3957927e
x86: Lift restriction on the location of FIX_BTMAP_*

The early ioremap fixmap entries cover half (or for 32-bit
non-PAE, a quarter) of a page table, yet they got
uncondtitionally aligned so far to a 256-entry boundary. This is
not necessary if the range of page table entries anyway falls
into a single page table.

This buys back, for (theoretically) 50% of all configurations
(25% of all non-PAE ones), at least some of the lowmem
necessarily lost with commit e621bd18958ef5dbace3129ebe17a0a475e127d9.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4B2BB66F0200007800026AD6@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/include/asm/fixmap.h
arch/x86/mm/ioremap.c