mirror of
https://github.com/torvalds/linux
synced 2024-09-06 18:01:05 +00:00
x86: add gbpages switches
These new controls toggle experimental support for a new CPU feature, the straightforward extension of largepages from the pmd level to the pud level, which allows 1GB (kernel) TLBs instead of 2MB TLBs. Turn it off by default, as this code has not been tested well enough yet. Use the CONFIG_DIRECT_GBPAGES=y .config option or gbpages on the boot line can be used to enable it. If enabled in the .config then nogbpages boot option disables it. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
parent
fe770bf031
commit
00d1c5e057
|
@ -307,3 +307,8 @@ Debugging
|
||||||
stuck (default)
|
stuck (default)
|
||||||
|
|
||||||
Miscellaneous
|
Miscellaneous
|
||||||
|
|
||||||
|
nogbpages
|
||||||
|
Do not use GB pages for kernel direct mappings.
|
||||||
|
gbpages
|
||||||
|
Use GB pages for kernel direct mappings.
|
||||||
|
|
|
@ -76,6 +76,18 @@ config DEBUG_RODATA
|
||||||
data. This is recommended so that we can catch kernel bugs sooner.
|
data. This is recommended so that we can catch kernel bugs sooner.
|
||||||
If in doubt, say "Y".
|
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
|
config DEBUG_RODATA_TEST
|
||||||
bool "Testcase for the DEBUG_RODATA feature"
|
bool "Testcase for the DEBUG_RODATA feature"
|
||||||
depends on DEBUG_RODATA
|
depends on DEBUG_RODATA
|
||||||
|
|
|
@ -54,6 +54,26 @@ static unsigned long dma_reserve __initdata;
|
||||||
|
|
||||||
DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
|
DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
|
||||||
|
|
||||||
|
int direct_gbpages __meminitdata
|
||||||
|
#ifdef CONFIG_DIRECT_GBPAGES
|
||||||
|
= 1
|
||||||
|
#endif
|
||||||
|
;
|
||||||
|
|
||||||
|
static int __init parse_direct_gbpages_off(char *arg)
|
||||||
|
{
|
||||||
|
direct_gbpages = 0;
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
early_param("nogbpages", parse_direct_gbpages_off);
|
||||||
|
|
||||||
|
static int __init parse_direct_gbpages_on(char *arg)
|
||||||
|
{
|
||||||
|
direct_gbpages = 1;
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
early_param("gbpages", parse_direct_gbpages_on);
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* NOTE: pagetable_init alloc all the fixmap pagetables contiguous on the
|
* NOTE: pagetable_init alloc all the fixmap pagetables contiguous on the
|
||||||
* physical space so we can cache the place of the first one and move
|
* physical space so we can cache the place of the first one and move
|
||||||
|
|
|
@ -239,6 +239,8 @@ static inline int pud_large(pud_t pte)
|
||||||
|
|
||||||
#define update_mmu_cache(vma,address,pte) do { } while (0)
|
#define update_mmu_cache(vma,address,pte) do { } while (0)
|
||||||
|
|
||||||
|
extern int direct_gbpages;
|
||||||
|
|
||||||
/* Encode and de-code a swap entry */
|
/* Encode and de-code a swap entry */
|
||||||
#define __swp_type(x) (((x).val >> 1) & 0x3f)
|
#define __swp_type(x) (((x).val >> 1) & 0x3f)
|
||||||
#define __swp_offset(x) ((x).val >> 8)
|
#define __swp_offset(x) ((x).val >> 8)
|
||||||
|
|
Loading…
Reference in a new issue