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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2013-07-24 00:11:42 +0400 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2013-08-29 15:20:11 +0400 |
| commit | 0944fe3f4a323f436180d39402cae7f9c46ead17 (patch) | |
| tree | 7b2ada69ff7e3c1fae20ec0b1dffe5e0d0ec2cc6 /include/asm-generic/pgtable.h | |
| parent | fbd70035fb2b03deb346052084794bc1d0e25aa2 (diff) | |
| download | linux-0944fe3f4a323f436180d39402cae7f9c46ead17.tar.xz | |
s390/mm: implement software referenced bits
The last remaining use for the storage key of the s390 architecture
is reference counting. The alternative is to make page table entries
invalid while they are old. On access the fault handler marks the
pte/pmd as young which makes the pte/pmd valid if the access rights
allow read access. The pte/pmd invalidations required for software
managed reference bits cost a bit of performance, on the other hand
the RRBE/RRBM instructions to read and reset the referenced bits are
quite expensive as well.
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'include/asm-generic/pgtable.h')
| -rw-r--r-- | include/asm-generic/pgtable.h | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index 0807ddf97b05..f330d28e4d0e 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -208,10 +208,6 @@ static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b) #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ #endif -#ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG -#define page_test_and_clear_young(pfn) (0) -#endif - #ifndef __HAVE_ARCH_PGD_OFFSET_GATE #define pgd_offset_gate(mm, addr) pgd_offset(mm, addr) #endif |