diff options
Diffstat (limited to 'arch/s390/mm/pgtable.c')
| -rw-r--r-- | arch/s390/mm/pgtable.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 3584ed9b20a1..9e2b4705dea2 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -17,6 +17,7 @@ #include <linux/quicklist.h> #include <linux/rcupdate.h> #include <linux/slab.h> +#include <linux/swapops.h> #include <asm/pgtable.h> #include <asm/pgalloc.h> @@ -594,6 +595,82 @@ unsigned long gmap_fault(unsigned long address, struct gmap *gmap) } EXPORT_SYMBOL_GPL(gmap_fault); +static void gmap_zap_swap_entry(swp_entry_t entry, struct mm_struct *mm) +{ + if (!non_swap_entry(entry)) + dec_mm_counter(mm, MM_SWAPENTS); + else if (is_migration_entry(entry)) { + struct page *page = migration_entry_to_page(entry); + + if (PageAnon(page)) + dec_mm_counter(mm, MM_ANONPAGES); + else + dec_mm_counter(mm, MM_FILEPAGES); + } + free_swap_and_cache(entry); +} + +/** + * The mm->mmap_sem lock must be held + */ +static void gmap_zap_unused(struct mm_struct *mm, unsigned long address) +{ + unsigned long ptev, pgstev; + spinlock_t *ptl; + pgste_t pgste; + pte_t *ptep, pte; + + ptep = get_locked_pte(mm, address, &ptl); + if (unlikely(!ptep)) + return; + pte = *ptep; + if (!pte_swap(pte)) + goto out_pte; + /* Zap unused and logically-zero pages */ + pgste = pgste_get_lock(ptep); + pgstev = pgste_val(pgste); + ptev = pte_val(pte); + if (((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED) || + ((pgstev & _PGSTE_GPS_ZERO) && (ptev & _PAGE_INVALID))) { + gmap_zap_swap_entry(pte_to_swp_entry(pte), mm); + pte_clear(mm, address, ptep); + } + pgste_set_unlock(ptep, pgste); +out_pte: + pte_unmap_unlock(*ptep, ptl); +} + +/* + * this function is assumed to be called with mmap_sem held + */ +void __gmap_zap(unsigned long address, struct gmap *gmap) +{ + unsigned long *table, *segment_ptr; + unsigned long segment, pgstev, ptev; + struct gmap_pgtable *mp; + struct page *page; + + segment_ptr = gmap_table_walk(address, gmap); + if (IS_ERR(segment_ptr)) + return; + segment = *segment_ptr; + if (segment & _SEGMENT_ENTRY_INVALID) + return; + page = pfn_to_page(segment >> PAGE_SHIFT); + mp = (struct gmap_pgtable *) page->index; + address = mp->vmaddr | (address & ~PMD_MASK); + /* Page table is present */ + table = (unsigned long *)(segment & _SEGMENT_ENTRY_ORIGIN); + table = table + ((address >> 12) & 0xff); + pgstev = table[PTRS_PER_PTE]; + ptev = table[0]; + /* quick check, checked again with locks held */ + if (((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED) || + ((pgstev & _PGSTE_GPS_ZERO) && (ptev & _PAGE_INVALID))) + gmap_zap_unused(gmap->mm, address); +} +EXPORT_SYMBOL_GPL(__gmap_zap); + void gmap_discard(unsigned long from, unsigned long to, struct gmap *gmap) { |