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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2013-07-24 00:11:42 +0400
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2013-08-29 15:20:11 +0400
commit0944fe3f4a323f436180d39402cae7f9c46ead17 (patch)
tree7b2ada69ff7e3c1fae20ec0b1dffe5e0d0ec2cc6 /include/asm-generic/pgtable.h
parentfbd70035fb2b03deb346052084794bc1d0e25aa2 (diff)
downloadlinux-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.h4
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