diff options
Diffstat (limited to 'sys/vm')
| -rw-r--r-- | sys/vm/vm_page.c | 57 | ||||
| -rw-r--r-- | sys/vm/vnode_pager.c | 2 |
2 files changed, 47 insertions, 12 deletions
diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c index 1ff371afb8c0..b29e30e029b9 100644 --- a/sys/vm/vm_page.c +++ b/sys/vm/vm_page.c @@ -170,6 +170,7 @@ TUNABLE_INT("vm.boot_pages", &boot_pages); SYSCTL_INT(_vm, OID_AUTO, boot_pages, CTLFLAG_RD, &boot_pages, 0, "number of pages allocated for bootstrapping the VM system"); +static void vm_page_clear_dirty_mask(vm_page_t m, int pagebits); static void vm_page_queue_remove(int queue, vm_page_t m); static void vm_page_enqueue(int queue, vm_page_t m); @@ -2073,6 +2074,28 @@ vm_page_set_valid(vm_page_t m, int base, int size) } /* + * Clear the given bits from the specified page's dirty field. + */ +static __inline void +vm_page_clear_dirty_mask(vm_page_t m, int pagebits) +{ + + /* + * If the object is locked and the page is neither VPO_BUSY nor + * PG_WRITEABLE, then the page's dirty field cannot possibly be + * modified by a concurrent pmap operation. + */ + VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); + if ((m->oflags & VPO_BUSY) == 0 && (m->flags & PG_WRITEABLE) == 0) + m->dirty &= ~pagebits; + else { + vm_page_lock_queues(); + m->dirty &= ~pagebits; + vm_page_unlock_queues(); + } +} + +/* * vm_page_set_validclean: * * Sets portions of a page valid and clean. The arguments are expected @@ -2087,9 +2110,8 @@ vm_page_set_valid(vm_page_t m, int base, int size) void vm_page_set_validclean(vm_page_t m, int base, int size) { - int pagebits; - int frag; - int endoff; + u_int oldvalid; + int endoff, frag, pagebits; VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); if (size == 0) /* handle degenerate case */ @@ -2126,6 +2148,7 @@ vm_page_set_validclean(vm_page_t m, int base, int size) * clear dirty bits for DEV_BSIZE chunks that are fully within * the range. */ + oldvalid = m->valid; pagebits = vm_page_bits(base, size); m->valid |= pagebits; #if 0 /* NOT YET */ @@ -2138,21 +2161,35 @@ vm_page_set_validclean(vm_page_t m, int base, int size) } pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1)); #endif - m->dirty &= ~pagebits; if (base == 0 && size == PAGE_SIZE) { - pmap_clear_modify(m); + /* + * The page can only be modified within the pmap if it is + * mapped, and it can only be mapped if it was previously + * fully valid. + */ + if (oldvalid == VM_PAGE_BITS_ALL) + /* + * Perform the pmap_clear_modify() first. Otherwise, + * a concurrent pmap operation, such as + * pmap_protect(), could clear a modification in the + * pmap and set the dirty field on the page before + * pmap_clear_modify() had begun and after the dirty + * field was cleared here. + */ + pmap_clear_modify(m); + m->dirty = 0; m->oflags &= ~VPO_NOSYNC; - } + } else if (oldvalid != VM_PAGE_BITS_ALL) + m->dirty &= ~pagebits; + else + vm_page_clear_dirty_mask(m, pagebits); } void vm_page_clear_dirty(vm_page_t m, int base, int size) { - VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED); - if ((m->flags & PG_WRITEABLE) != 0) - mtx_assert(&vm_page_queue_mtx, MA_OWNED); - m->dirty &= ~vm_page_bits(base, size); + vm_page_clear_dirty_mask(m, vm_page_bits(base, size)); } /* diff --git a/sys/vm/vnode_pager.c b/sys/vm/vnode_pager.c index c1f8cff5867a..f497d41a0eb3 100644 --- a/sys/vm/vnode_pager.c +++ b/sys/vm/vnode_pager.c @@ -429,9 +429,7 @@ vnode_pager_setsize(vp, nsize) * bits. This would prevent bogus_page * replacement from working properly. */ - vm_page_lock_queues(); vm_page_clear_dirty(m, base, PAGE_SIZE - base); - vm_page_unlock_queues(); } else if ((nsize & PAGE_MASK) && __predict_false(object->cache != NULL)) { vm_page_cache_free(object, OFF_TO_IDX(nsize), |