ia64/linux-2.6.18-xen.hg

view arch/mips/pci/fixup-ddb5477.c @ 897:329ea0ccb344

balloon: try harder to balloon up under memory pressure.

Currently if the balloon driver is unable to increase the guest's
reservation it assumes the failure was due to reaching its full
allocation, gives up on the ballooning operation and records the limit
it reached as the "hard limit". The driver will not try again until
the target is set again (even to the same value).

However it is possible that ballooning has in fact failed due to
memory pressure in the host and therefore it is desirable to keep
attempting to reach the target in case memory becomes available. The
most likely scenario is that some guests are ballooning down while
others are ballooning up and therefore there is temporary memory
pressure while things stabilise. You would not expect a well behaved
toolstack to ask a domain to balloon to more than its allocation nor
would you expect it to deliberately over-commit memory by setting
balloon targets which exceed the total host memory.

This patch drops the concept of a hard limit and causes the balloon
driver to retry increasing the reservation on a timer in the same
manner as when decreasing the reservation.

Also if we partially succeed in increasing the reservation
(i.e. receive less pages than we asked for) then we may as well keep
those pages rather than returning them to Xen.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Fri Jun 05 14:01:20 2009 +0100 (2009-06-05)
parents 831230e53067
children
line source
1 /*
2 *
3 * BRIEF MODULE DESCRIPTION
4 * Board specific pci fixups.
5 *
6 * Copyright 2001, 2002, 2003 MontaVista Software Inc.
7 * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the
11 * Free Software Foundation; either version 2 of the License, or (at your
12 * option) any later version.
13 *
14 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
15 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
16 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
17 * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
20 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
21 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 *
25 * You should have received a copy of the GNU General Public License along
26 * with this program; if not, write to the Free Software Foundation, Inc.,
27 * 675 Mass Ave, Cambridge, MA 02139, USA.
28 */
30 #include <linux/types.h>
31 #include <linux/pci.h>
32 #include <linux/kernel.h>
33 #include <linux/init.h>
35 static void ddb5477_fixup(struct pci_dev *dev)
36 {
37 u8 old;
39 printk(KERN_NOTICE "Enabling ALI M1533/35 PS2 keyboard/mouse.\n");
40 pci_read_config_byte(dev, 0x41, &old);
41 pci_write_config_byte(dev, 0x41, old | 0xd0);
42 }
44 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
45 ddb5477_fixup);
46 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1535,
47 ddb5477_fixup);
49 /*
50 * Fixup baseboard AMD chip so that tx does not underflow.
51 * bcr_18 |= 0x0800
52 * This sets NOUFLO bit which makes tx not start until whole pkt
53 * is fetched to the chip.
54 */
55 #define PCNET32_WIO_RDP 0x10
56 #define PCNET32_WIO_RAP 0x12
57 #define PCNET32_WIO_RESET 0x14
58 #define PCNET32_WIO_BDP 0x16
60 static void ddb5477_amd_lance_fixup(struct pci_dev *dev)
61 {
62 unsigned long ioaddr;
63 u16 temp;
65 ioaddr = pci_resource_start(dev, 0);
67 inw(ioaddr + PCNET32_WIO_RESET); /* reset chip */
69 /* bcr_18 |= 0x0800 */
70 outw(18, ioaddr + PCNET32_WIO_RAP);
71 temp = inw(ioaddr + PCNET32_WIO_BDP);
72 temp |= 0x0800;
73 outw(18, ioaddr + PCNET32_WIO_RAP);
74 outw(temp, ioaddr + PCNET32_WIO_BDP);
75 }
77 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_LANCE,
78 ddb5477_amd_lance_fixup);