diff options
Diffstat (limited to 'arch/s390/mm/gmap.c')
| -rw-r--r-- | arch/s390/mm/gmap.c | 39 |
1 files changed, 32 insertions, 7 deletions
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 53292c03e312..9e1494e3d849 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -2121,6 +2121,37 @@ static inline void thp_split_mm(struct mm_struct *mm) } /* + * Remove all empty zero pages from the mapping for lazy refaulting + * - This must be called after mm->context.has_pgste is set, to avoid + * future creation of zero pages + * - This must be called after THP was enabled + */ +static int __zap_zero_pages(pmd_t *pmd, unsigned long start, + unsigned long end, struct mm_walk *walk) +{ + unsigned long addr; + + for (addr = start; addr != end; addr += PAGE_SIZE) { + pte_t *ptep; + spinlock_t *ptl; + + ptep = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); + if (is_zero_pfn(pte_pfn(*ptep))) + ptep_xchg_direct(walk->mm, addr, ptep, __pte(_PAGE_INVALID)); + pte_unmap_unlock(ptep, ptl); + } + return 0; +} + +static inline void zap_zero_pages(struct mm_struct *mm) +{ + struct mm_walk walk = { .pmd_entry = __zap_zero_pages }; + + walk.mm = mm; + walk_page_range(0, TASK_SIZE, &walk); +} + +/* * switch on pgstes for its userspace process (for kvm) */ int s390_enable_sie(void) @@ -2137,6 +2168,7 @@ int s390_enable_sie(void) mm->context.has_pgste = 1; /* split thp mappings and disable thp for future mappings */ thp_split_mm(mm); + zap_zero_pages(mm); up_write(&mm->mmap_sem); return 0; } @@ -2149,13 +2181,6 @@ EXPORT_SYMBOL_GPL(s390_enable_sie); static int __s390_enable_skey(pte_t *pte, unsigned long addr, unsigned long next, struct mm_walk *walk) { - /* - * Remove all zero page mappings, - * after establishing a policy to forbid zero page mappings - * following faults for that page will get fresh anonymous pages - */ - if (is_zero_pfn(pte_pfn(*pte))) - ptep_xchg_direct(walk->mm, addr, pte, __pte(_PAGE_INVALID)); /* Clear storage key */ ptep_zap_key(walk->mm, addr, pte); return 0; |