[PATCH 03/04 v2] kvm-s390: Improve pgste accesses

Carsten Otte
2008-04-04T14:03:34Z

From: Heiko Carstens <heiko.carstens@de.ibm.com>

There is no need to use interlocked updates when the rcp
lock is held. Therefore the simple bitops variants can be
used. This should improve performance.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
---
include/asm-s390/pgtable.h | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

Index: kvm/include/asm-s390/pgtable.h
===================================================================
--- kvm.orig/include/asm-s390/pgtable.h
+++ kvm/include/asm-s390/pgtable.h
@@ -553,12 +553,12 @@ static inline void ptep_rcp_copy(pte_t *

skey = page_get_storage_key(page_to_phys(page));
if (skey & _PAGE_CHANGED)
- set_bit(RCP_GC_BIT, pgste);
+ set_bit_simple(RCP_GC_BIT, pgste);
if (skey & _PAGE_REFERENCED)
- set_bit(RCP_GR_BIT, pgste);
- if (test_and_clear_bit(RCP_HC_BIT, pgste))
+ set_bit_simple(RCP_GR_BIT, pgste);
+ if (test_and_clear_bit_simple(RCP_HC_BIT, pgste))
SetPageDirty(page);
- if (test_and_clear_bit(RCP_HR_BIT, pgste))
+ if (test_and_clear_bit_simple(RCP_HR_BIT, pgste))
SetPageReferenced(page);
#endif
}
@@ -732,8 +732,8 @@ static inline int ptep_test_and_clear_yo
young = ((page_get_storage_key(physpage) & _PAGE_REFERENCED) != 0);
rcp_lock(ptep);
if (young)
- set_bit(RCP_GR_BIT, pgste);
- young |= test_and_clear_bit(RCP_HR_BIT, pgste);
+ set_bit_simple(RCP_GR_BIT, pgste);
+ young |= test_and_clear_bit_simple(RCP_HR_BIT, pgste);
rcp_unlock(ptep);
return young;
#endif