[src/trunk]: src/sys/uvm uvm_anon_freelst: do not free PG_RELEASED pages (cha...

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

details:   https://anonhg.NetBSD.org/src/rev/2dc83d4a7788
branches:  trunk
changeset: 768292:2dc83d4a7788
user:      rmind <rmind%NetBSD.org@localhost>
date:      Sun Aug 14 01:20:33 2011 +0000

description:
uvm_anon_freelst: do not free PG_RELEASED pages (change uvm_anon_dispose()
to indicate them with a return value).

diffstat:

 sys/uvm/uvm_anon.c |  25 +++++++++++++++++--------
 1 files changed, 17 insertions(+), 8 deletions(-)

diffs (71 lines):

diff -r ec650a305ed9 -r 2dc83d4a7788 sys/uvm/uvm_anon.c
--- a/sys/uvm/uvm_anon.c        Sat Aug 13 23:12:15 2011 +0000
+++ b/sys/uvm/uvm_anon.c        Sun Aug 14 01:20:33 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_anon.c,v 1.59 2011/08/06 17:25:03 rmind Exp $      */
+/*     $NetBSD: uvm_anon.c,v 1.60 2011/08/14 01:20:33 rmind Exp $      */
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_anon.c,v 1.59 2011/08/06 17:25:03 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_anon.c,v 1.60 2011/08/14 01:20:33 rmind Exp $");
 
 #include "opt_uvmhist.h"
 
@@ -99,8 +99,7 @@
  * => anon must be removed from the amap (if anon was in an amap).
  * => amap must be locked; we may drop and re-acquire the lock here.
  */
-
-static void
+static bool
 uvm_anon_dispose(struct vm_anon *anon)
 {
        struct vm_page *pg = anon->an_page;
@@ -159,7 +158,7 @@
                        if (pg->flags & PG_BUSY) {
                                pg->flags |= PG_RELEASED;
                                mutex_obj_hold(anon->an_lock);
-                               return;
+                               return false;
                        }
                        mutex_enter(&uvm_pageqlock);
                        uvm_pagefree(pg);
@@ -186,6 +185,7 @@
        uvm_anon_dropswap(anon);
        uvmpdpol_anfree(anon);
        UVMHIST_LOG(maphist,"<- done!",0,0,0,0);
+       return true;
 }
 
 /*
@@ -214,13 +214,22 @@
 void
 uvm_anon_freelst(struct vm_amap *amap, struct vm_anon *anonlst)
 {
-       struct vm_anon *anon = anonlst;
+       struct vm_anon *anon = anonlst, *prev = NULL, *next;
 
        KASSERT(mutex_owned(amap->am_lock));
 
        while (anon) {
-               uvm_anon_dispose(anon);
-               anon = anon->an_link;
+               next = anon->an_link;
+               if (!uvm_anon_dispose(anon)) {
+                       /* Do not free this anon. */
+                       if (prev) {
+                               prev->an_link = next;
+                       } else {
+                               anonlst = next;
+                       }
+               }
+               prev = anon;
+               anon = next;
        }
        amap_unlock(amap);