[src/trunk]: src/sys/rump/librump/rumpkern reserve a small amount of memory f...

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

details:   https://anonhg.NetBSD.org/src/rev/18e78211143d
branches:  trunk
changeset: 326783:18e78211143d
user:      pooka <pooka%NetBSD.org@localhost>
date:      Mon Feb 17 19:33:05 2014 +0000

description:
reserve a small amount of memory for the pagedaemon

diffstat:

 sys/rump/librump/rumpkern/vm.c |  25 ++++++++++++++++++-------
 1 files changed, 18 insertions(+), 7 deletions(-)

diffs (70 lines):

diff -r f2bb8079a811 -r 18e78211143d sys/rump/librump/rumpkern/vm.c
--- a/sys/rump/librump/rumpkern/vm.c    Mon Feb 17 19:30:12 2014 +0000
+++ b/sys/rump/librump/rumpkern/vm.c    Mon Feb 17 19:33:05 2014 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vm.c,v 1.146 2013/11/23 22:24:31 christos Exp $        */
+/*     $NetBSD: vm.c,v 1.147 2014/02/17 19:33:05 pooka Exp $   */
 
 /*
  * Copyright (c) 2007-2011 Antti Kantee.  All Rights Reserved.
@@ -41,7 +41,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vm.c,v 1.146 2013/11/23 22:24:31 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vm.c,v 1.147 2014/02/17 19:33:05 pooka Exp $");
 
 #include <sys/param.h>
 #include <sys/atomic.h>
@@ -94,6 +94,7 @@
 static kcondvar_t pdaemoncv, oomwait;
 
 unsigned long rump_physmemlimit = RUMPMEM_UNLIMITED;
+static unsigned long pdlimit = RUMPMEM_UNLIMITED; /* page daemon memlimit */
 static unsigned long curphysmem;
 static unsigned long dddlim;           /* 90% of memory limit used */
 #define NEED_PAGEDAEMON() \
@@ -305,8 +306,13 @@
                if (rump_physmemlimit / mult != tmp)
                        panic("uvm_init: RUMP_MEMLIMIT overflow: %s", buf);
                /* it's not like we'd get far with, say, 1 byte, but ... */
-               if (rump_physmemlimit == 0)
-                       panic("uvm_init: no memory");
+               if (rump_physmemlimit < 2*MAXPHYS)
+                       panic("uvm_init: no memory, need at least %d bytes",
+                           2*MAXPHYS);
+
+               /* reserve some memory for the pager */
+               pdlimit = rump_physmemlimit;
+               rump_physmemlimit -= 2*MAXPHYS;
 
 #define HUMANIZE_BYTES 9
                CTASSERT(sizeof(buf) >= HUMANIZE_BYTES);
@@ -919,11 +925,15 @@
 uvm_wait(const char *msg)
 {
 
-       if (__predict_false(curlwp == uvm.pagedaemon_lwp))
-               panic("pagedaemon out of memory");
        if (__predict_false(rump_threads == 0))
                panic("pagedaemon missing (RUMP_THREADS = 0)");
 
+       if (curlwp == uvm.pagedaemon_lwp) {
+               /* is it possible for us to later get memory? */
+               if (!uvmexp.paging)
+                       panic("pagedaemon out of memory");
+       }
+
        mutex_enter(&pdaemonmtx);
        pdaemon_waiters++;
        cv_signal(&pdaemoncv);
@@ -1158,7 +1168,8 @@
  limitagain:
        if (rump_physmemlimit != RUMPMEM_UNLIMITED) {
                newmem = atomic_add_long_nv(&curphysmem, howmuch);
-               if (newmem > rump_physmemlimit) {
+               if ((newmem > rump_physmemlimit) &&
+                   !(curlwp == uvm.pagedaemon_lwp || newmem > pdlimit)) {
                        newmem = atomic_add_long_nv(&curphysmem, -howmuch);
                        if (!waitok) {
                                return NULL;