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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2010-10-25 18:10:07 +0400 |
|---|---|---|
| committer | Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com> | 2010-10-25 18:10:14 +0400 |
| commit | 238ec4efeee4461d5cff2ed3e5a15a3ab850959b (patch) | |
| tree | d9efb4be22cc550c7559c29627a48d66413c645a /arch/s390/include/asm | |
| parent | 229aebb873e29726b91e076161649cf45154b0bf (diff) | |
| download | linux-238ec4efeee4461d5cff2ed3e5a15a3ab850959b.tar.xz | |
[S390] zero page cache synonyms
If the zero page is mapped to virtual user space addresses that differ
only in bit 2^12 or 2^13 we get L1 cache synonyms which can affect
performance. Follow the mips model and use multiple zero pages to avoid
the synonyms.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include/asm')
| -rw-r--r-- | arch/s390/include/asm/pgtable.h | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 3157441ee1da..22a294571000 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -46,11 +46,27 @@ extern void vmem_map_init(void); #define update_mmu_cache(vma, address, ptep) do { } while (0) /* - * ZERO_PAGE is a global shared page that is always zero: used + * ZERO_PAGE is a global shared page that is always zero; used * for zero-mapped memory areas etc.. */ -extern char empty_zero_page[PAGE_SIZE]; -#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page)) + +extern unsigned long empty_zero_page; +extern unsigned long zero_page_mask; + +#define ZERO_PAGE(vaddr) \ + (virt_to_page((void *)(empty_zero_page + \ + (((unsigned long)(vaddr)) &zero_page_mask)))) + +#define is_zero_pfn is_zero_pfn +static inline int is_zero_pfn(unsigned long pfn) +{ + extern unsigned long zero_pfn; + unsigned long offset_from_zero_pfn = pfn - zero_pfn; + return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT); +} + +#define my_zero_pfn(addr) page_to_pfn(ZERO_PAGE(addr)) + #endif /* !__ASSEMBLY__ */ /* |