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x86/mm: Further simplify 1 GB kernel linear mappings handling 

It's a bit pointless to allow Kconfig configuration for 1GB kernel
mappings, it's already hidden behind a 'default y' and CONFIG_EXPERT.

Remove this complication and simplify the code by renaming
CONFIG_ENABLE_DIRECT_GBPAGES to CONFIG_X86_DIRECT_GBPAGES and
document the DEBUG_PAGE_ALLOC and KMEMCHECK quirks.

Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: JBeulich@suse.com
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: julia.lawall@lip6.fr
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2015-03-05 08:18:23 +01:00
parent 73c8c861dc
commit 10971ab269
2 changed files with 6 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
arch/x86/Kconfig
View File

@ -1299,22 +1299,14 @@ config ARCH_DMA_ADDR_T_64BIT
def_bool y
depends on X86_64 || HIGHMEM64G
config ENABLE_DIRECT_GBPAGES
config X86_DIRECT_GBPAGES
def_bool y
depends on X86_64 && !DEBUG_PAGEALLOC && !KMEMCHECK
config DIRECT_GBPAGES
bool "Enable 1GB pages for kernel pagetables" if EXPERT
default y
depends on ENABLE_DIRECT_GBPAGES
---help---
Enable by default 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". If you've disabled
option but your platform is capable of handling support for this
you can use the gbpages kernel parameter. Likewise if you've enabled
this but you'd like to force disable this option you can use the
nogbpages kernel parameter.
Certain kernel features effectively disable kernel
linear 1 GB mappings (even if the CPU otherwise
supports them), so don't confuse the user by printing
that we have them enabled.
# Common NUMA Features
config NUMA

7
arch/x86/mm/init.c
View File

@ -133,15 +133,10 @@ int after_bootmem;
static int page_size_mask;
early_param_on_off("gbpages", "nogbpages",
direct_gbpages, CONFIG_DIRECT_GBPAGES);
early_param_on_off("gbpages", "nogbpages", direct_gbpages, CONFIG_X86_DIRECT_GBPAGES);
static void __init init_gbpages(void)
{
if (!IS_ENABLED(CONFIG_ENABLE_DIRECT_GBPAGES)) {
direct_gbpages = 0;
return;
}
if (direct_gbpages && cpu_has_gbpages) {
printk(KERN_INFO "Using GB pages for direct mapping\n");
page_size_mask |= 1 << PG_LEVEL_1G;