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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2015-09-29 12:51:40 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2015-10-14 14:32:07 +0200 |
| commit | 395e6aa1d0ffbc493a04469aa8f6751ed2aad8c5 (patch) | |
| tree | 2ce127f327fc349098908385a0b564ae6136887f | |
| parent | 5da7667c035f3a711ec8d0a3997254807dd8bc6d (diff) | |
| download | linux-395e6aa1d0ffbc493a04469aa8f6751ed2aad8c5.tar.bz2 | |
s390/mm: try to avoid storage key operation in ptep_set_access_flags
The call to pgste_set_key in ptep_set_access_flags can be avoided
if the old pte is found to be valid at the time the new access
rights are set. The function that created the old, valid pte already
completed the required storage key operation.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
| -rw-r--r-- | arch/s390/include/asm/pgtable.h | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 4d7e2e94082e..024f85f947ae 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -1267,8 +1267,10 @@ static inline int ptep_set_access_flags(struct vm_area_struct *vma, pte_t entry, int dirty) { pgste_t pgste; + pte_t oldpte; - if (pte_same(*ptep, entry)) + oldpte = *ptep; + if (pte_same(oldpte, entry)) return 0; if (mm_has_pgste(vma->vm_mm)) { pgste = pgste_get_lock(ptep); @@ -1278,7 +1280,8 @@ static inline int ptep_set_access_flags(struct vm_area_struct *vma, ptep_flush_direct(vma->vm_mm, address, ptep); if (mm_has_pgste(vma->vm_mm)) { - pgste_set_key(ptep, pgste, entry, vma->vm_mm); + if (pte_val(oldpte) & _PAGE_INVALID) + pgste_set_key(ptep, pgste, entry, vma->vm_mm); pgste = pgste_set_pte(ptep, pgste, entry); pgste_set_unlock(ptep, pgste); } else |