[patch] x86: enable GBPAGES option by default

[patch] x86: enable GBPAGES option by default

[Nick Piggin]

DIRECT_GBPAGES was under DEBUG_KERNEL && EXPERIMENTAL and disabled by default.
Turn it on by default and put it under EMBEDDED.

Signed-off-by: Nick Piggin <npiggin@suse.de>
---
Index: linux-2.6/arch/x86/Kconfig
===================================================================
--- linux-2.6.orig/arch/x86/Kconfig
+++ linux-2.6/arch/x86/Kconfig
@@ -946,6 +946,15 @@ config X86_PAE
 config ARCH_PHYS_ADDR_T_64BIT
        def_bool X86_64 || X86_PAE
 
+config DIRECT_GBPAGES
+	bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
+	default y
+	depends on X86_64
+	help
+	  Allow the kernel linear mapping to use 1GB pages on CPUs that
+	  support it. This can improve the kernel's performance a tiny bit by
+	  reducing TLB pressure. If in doubt, say "Y".
+
 # Common NUMA Features
 config NUMA
 	bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
Index: linux-2.6/arch/x86/Kconfig.debug
===================================================================
--- linux-2.6.orig/arch/x86/Kconfig.debug
+++ linux-2.6/arch/x86/Kconfig.debug
@@ -114,18 +114,6 @@ config DEBUG_RODATA
 	  data. This is recommended so that we can catch kernel bugs sooner.
 	  If in doubt, say "Y".
 
-config DIRECT_GBPAGES
-	bool "Enable gbpages-mapped kernel pagetables"
-	depends on DEBUG_KERNEL && EXPERIMENTAL && X86_64
-	help
-	  Enable gigabyte pages support (if the CPU supports it). This can
-	  improve the kernel's performance a tiny bit by reducing TLB
-	  pressure.
-
-	  This is experimental code.
-
-	  If in doubt, say "N".
-
 config DEBUG_RODATA_TEST
 	bool "Testcase for the DEBUG_RODATA feature"
 	depends on DEBUG_RODATA

Re: [patch] x86: enable GBPAGES option by default

[Nick Piggin]

Oops, messed up Andi's email...

On Wed, Oct 22, 2008 at 12:33:16PM +0200, Nick Piggin wrote:
> DIRECT_GBPAGES was under DEBUG_KERNEL && EXPERIMENTAL and disabled by default.
> Turn it on by default and put it under EMBEDDED.
> 
> Signed-off-by: Nick Piggin <npiggin@suse.de>
> ---
> Index: linux-2.6/arch/x86/Kconfig
> ===================================================================
> --- linux-2.6.orig/arch/x86/Kconfig
> +++ linux-2.6/arch/x86/Kconfig
> @@ -946,6 +946,15 @@ config X86_PAE
>  config ARCH_PHYS_ADDR_T_64BIT
>         def_bool X86_64 || X86_PAE
>  
> +config DIRECT_GBPAGES
> +	bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
> +	default y
> +	depends on X86_64
> +	help
> +	  Allow the kernel linear mapping to use 1GB pages on CPUs that
> +	  support it. This can improve the kernel's performance a tiny bit by
> +	  reducing TLB pressure. If in doubt, say "Y".
> +
>  # Common NUMA Features
>  config NUMA
>  	bool "Numa Memory Allocation and Scheduler Support (EXPERIMENTAL)"
> Index: linux-2.6/arch/x86/Kconfig.debug
> ===================================================================
> --- linux-2.6.orig/arch/x86/Kconfig.debug
> +++ linux-2.6/arch/x86/Kconfig.debug
> @@ -114,18 +114,6 @@ config DEBUG_RODATA
>  	  data. This is recommended so that we can catch kernel bugs sooner.
>  	  If in doubt, say "Y".
>  
> -config DIRECT_GBPAGES
> -	bool "Enable gbpages-mapped kernel pagetables"
> -	depends on DEBUG_KERNEL && EXPERIMENTAL && X86_64
> -	help
> -	  Enable gigabyte pages support (if the CPU supports it). This can
> -	  improve the kernel's performance a tiny bit by reducing TLB
> -	  pressure.
> -
> -	  This is experimental code.
> -
> -	  If in doubt, say "N".
> -
>  config DEBUG_RODATA_TEST
>  	bool "Testcase for the DEBUG_RODATA feature"
>  	depends on DEBUG_RODATA

Re: [patch] x86: enable GBPAGES option by default

[Ingo Molnar]

* Nick Piggin <npiggin@suse.de> wrote:

> DIRECT_GBPAGES was under DEBUG_KERNEL && EXPERIMENTAL and disabled by 
> default. Turn it on by default and put it under EMBEDDED.
> 
> Signed-off-by: Nick Piggin <npiggin@suse.de>

applied to tip/x86/mm, thanks Nick!

	Ingo