Eliminate (many) unnecessary calls to pmap_remove_all(). Pages from objects

with a reference count of zero can't possibly be mapped, so there is never a
need for vm_page_set_invalid() to call pmap_remove_all() on them.

Reviewed by:	kib
MFC after:	1 week
Sponsored by:	EMC / Isilon Storage Division

diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index 9c4890f2c303f8f9de2e6b33521d2020c834b524..db4db2ea85fd0c81e936cf52cffe7dc5db3bce0e 100644 (file)
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -3096,7 +3096,8 @@ vm_page_set_invalid(vm_page_t m, int base, int size)
                bits = VM_PAGE_BITS_ALL;
        else
                bits = vm_page_bits(base, size);
-       if (m->valid == VM_PAGE_BITS_ALL && bits != 0)
+       if (object->ref_count != 0 && m->valid == VM_PAGE_BITS_ALL &&
+           bits != 0)
                pmap_remove_all(m);
        KASSERT((bits == 0 && m->valid == VM_PAGE_BITS_ALL) ||
            !pmap_page_is_mapped(m),