[src/rmind-uvmplock]: src/sys/uvm ubc_alloc: when replacing a cache entry, lo...

[rmind <rmind%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/5d4aedf8bcab
branches:  rmind-uvmplock
changeset: 753054:5d4aedf8bcab
user:      rmind <rmind%NetBSD.org@localhost>
date:      Sun Apr 25 22:48:26 2010 +0000

description:
ubc_alloc: when replacing a cache entry, lock the old object from which we
are deassociating and removing the old mapping.

diffstat:

 sys/uvm/uvm_bio.c |  29 +++++++++++++++++++----------
 1 files changed, 19 insertions(+), 10 deletions(-)

diffs (73 lines):

diff -r dfc7b31db4c8 -r 5d4aedf8bcab sys/uvm/uvm_bio.c
--- a/sys/uvm/uvm_bio.c Sun Apr 25 21:08:41 2010 +0000
+++ b/sys/uvm/uvm_bio.c Sun Apr 25 22:48:26 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_bio.c,v 1.68.4.2 2010/03/17 06:03:17 rmind Exp $   */
+/*     $NetBSD: uvm_bio.c,v 1.68.4.3 2010/04/25 22:48:26 rmind Exp $   */
 
 /*
  * Copyright (c) 1998 Chuck Silvers.
@@ -34,7 +34,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_bio.c,v 1.68.4.2 2010/03/17 06:03:17 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_bio.c,v 1.68.4.3 2010/04/25 22:48:26 rmind Exp $");
 
 #include "opt_uvmhist.h"
 #include "opt_ubc.h"
@@ -448,13 +448,15 @@
        *lenp = MIN(*lenp, ubc_winsize - slot_offset);
 
        /*
-        * the object is always locked here, so we don't need to add a ref.
+        * The object is already referenced, so we do not need to add a ref.
         */
 
        mutex_enter(ubc_object.uobj.vmobjlock);
 again:
        umap = ubc_find_mapping(uobj, umap_offset);
        if (umap == NULL) {
+               struct uvm_object *oobj;
+
                UBC_EVCNT_INCR(wincachemiss);
                umap = TAILQ_FIRST(UBC_QUEUE(offset));
                if (umap == NULL) {
@@ -463,23 +465,30 @@
                        goto again;
                }
 
+               va = UBC_UMAP_ADDR(umap);
+               oobj = umap->uobj;
+
                /*
                 * remove from old hash (if any), add to new hash.
                 */
 
-               if (umap->uobj != NULL) {
+               if (oobj != NULL) {
                        LIST_REMOVE(umap, hash);
+                       if (umap->flags & UMAP_MAPPING_CACHED) {
+                               umap->flags &= ~UMAP_MAPPING_CACHED;
+                               mutex_enter(oobj->vmobjlock);
+                               pmap_remove(pmap_kernel(), va,
+                                   va + ubc_winsize);
+                               mutex_exit(oobj->vmobjlock);
+                               pmap_update(pmap_kernel());
+                       }
+               } else {
+                       KASSERT((umap->flags & UMAP_MAPPING_CACHED) == 0);
                }
                umap->uobj = uobj;
                umap->offset = umap_offset;
                LIST_INSERT_HEAD(&ubc_object.hash[UBC_HASH(uobj, umap_offset)],
                    umap, hash);
-               va = UBC_UMAP_ADDR(umap);
-               if (umap->flags & UMAP_MAPPING_CACHED) {
-                       umap->flags &= ~UMAP_MAPPING_CACHED;
-                       pmap_remove(pmap_kernel(), va, va + ubc_winsize);
-                       pmap_update(pmap_kernel());
-               }
        } else {
                UBC_EVCNT_INCR(wincachehit);
                va = UBC_UMAP_ADDR(umap);