[src/trunk]: src/sys/rump/librump/rumpkern Make uvm_pagealloc_tele() fail if ...

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

details:   https://anonhg.NetBSD.org/src/rev/216ce22c9c02
branches:  trunk
changeset: 759192:216ce22c9c02
user:      pooka <pooka%NetBSD.org@localhost>
date:      Wed Dec 01 11:19:18 2010 +0000

description:
Make uvm_pagealloc_tele() fail if the request can't be immediately
satisfied.  This allows the caller to unlock the object and the
pagedaemon to avoid deadlock even if ~all memory is consumed by
one vm object.  This in turn makes is possible to copy a large file
into a rump kernel with a 10MB memory limit (where large >> 10MB).
A little more tuning will be required to avoid the pagedaemon
hitting the sleep-and-retry path, though.

+ fix some outdated unrelated comments

diffstat:

 sys/rump/librump/rumpkern/vm.c |  23 +++++++++++++----------
 1 files changed, 13 insertions(+), 10 deletions(-)

diffs (73 lines):

diff -r c0c0dc4232f3 -r 216ce22c9c02 sys/rump/librump/rumpkern/vm.c
--- a/sys/rump/librump/rumpkern/vm.c    Wed Dec 01 09:52:28 2010 +0000
+++ b/sys/rump/librump/rumpkern/vm.c    Wed Dec 01 11:19:18 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vm.c,v 1.102 2010/11/22 20:42:19 pooka Exp $   */
+/*     $NetBSD: vm.c,v 1.103 2010/12/01 11:19:18 pooka Exp $   */
 
 /*
  * Copyright (c) 2007-2010 Antti Kantee.  All Rights Reserved.
@@ -41,7 +41,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vm.c,v 1.102 2010/11/22 20:42:19 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vm.c,v 1.103 2010/12/01 11:19:18 pooka Exp $");
 
 #include <sys/param.h>
 #include <sys/atomic.h>
@@ -146,8 +146,9 @@
        struct vm_page *pg = obj;
 
        memset(pg, 0, sizeof(*pg));
-       pg->uanon = rump_hypermalloc(PAGE_SIZE, PAGE_SIZE, true, "pgalloc");
-       return 0;
+       pg->uanon = rump_hypermalloc(PAGE_SIZE, PAGE_SIZE,
+           (flags & PR_WAITOK) == PR_WAITOK, "pgalloc");
+       return pg->uanon == NULL;
 }
 
 static void
@@ -172,7 +173,10 @@
        KASSERT(uobj && mutex_owned(&uobj->vmobjlock));
        KASSERT(anon == NULL);
 
-       pg = pool_cache_get(&pagecache, PR_WAITOK);
+       pg = pool_cache_get(&pagecache, PR_NOWAIT);
+       if (__predict_false(pg == NULL))
+               return NULL;
+
        pg->offset = off;
        pg->uobject = uobj;
 
@@ -326,8 +330,7 @@
 /*
  * This satisfies the "disgusting mmap hack" used by proplib.
  * We probably should grow some more assertables to make sure we're
- * not satisfying anything we shouldn't be satisfying.  At least we
- * should make sure it's the local machine we're mmapping ...
+ * not satisfying anything we shouldn't be satisfying.
  */
 int
 uvm_mmap(struct vm_map *map, vaddr_t *addr, vsize_t size, vm_prot_t prot,
@@ -760,8 +763,7 @@
 {
 
        /*
-        * there is only vmspace0.  we're not planning on
-        * feeding it to the fishes.
+        * No dynamically allocated vmspaces exist.
         */
 }
 
@@ -1052,8 +1054,9 @@
                newmem = atomic_add_long_nv(&curphysmem, howmuch);
                if (newmem > rump_physmemlimit) {
                        newmem = atomic_add_long_nv(&curphysmem, -howmuch);
-                       if (!waitok)
+                       if (!waitok) {
                                return NULL;
+                       }
                        uvm_wait(wmsg);
                        goto limitagain;
                }