1 From: Nick Piggin <npiggin@suse.de>
2 Subject: Enable GB mapped linear KVA on x86
4 Patch-upstream: should be in 2.6.28 or 29
6 GBPAGES should be turned on in SUSE x86-64 kernels.
8 Signed-off-by: Nick Piggin <npiggin@suse.de>
11 arch/x86/Kconfig | 9 +++++++++
12 arch/x86/Kconfig.debug | 12 ------------
13 2 files changed, 9 insertions(+), 12 deletions(-)
15 --- a/arch/x86/Kconfig
16 +++ b/arch/x86/Kconfig
17 @@ -960,6 +960,15 @@ config X86_PAE
18 has the cost of more pagetable lookup overhead, and also
19 consumes more pagetable space per process.
21 +config DIRECT_GBPAGES
22 + bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
26 + Allow the kernel linear mapping to use 1GB pages on CPUs that
27 + support it. This can improve the kernel's performance a tiny bit by
28 + reducing TLB pressure. If in doubt, say "Y".
30 # Common NUMA Features
32 bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
33 --- a/arch/x86/Kconfig.debug
34 +++ b/arch/x86/Kconfig.debug
35 @@ -114,18 +114,6 @@ config DEBUG_RODATA
36 data. This is recommended so that we can catch kernel bugs sooner.
39 -config DIRECT_GBPAGES
40 - bool "Enable gbpages-mapped kernel pagetables"
41 - depends on DEBUG_KERNEL && EXPERIMENTAL && X86_64
43 - Enable gigabyte pages support (if the CPU supports it). This can
44 - improve the kernel's performance a tiny bit by reducing TLB
47 - This is experimental code.
49 - If in doubt, say "N".
51 config DEBUG_RODATA_TEST
52 bool "Testcase for the DEBUG_RODATA feature"
53 depends on DEBUG_RODATA