ia64/linux-2.6.18-xen.hg

view arch/mips/pci/fixup-atlas.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 * Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org)
3 * Copyright (C) 2005 MIPS Technologies, Inc. All rights reserved.
4 * Author: Maciej W. Rozycki <macro@mips.com>
5 *
6 * This program is free software; you can distribute it and/or modify it
7 * under the terms of the GNU General Public License (Version 2) as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * for more details.
14 *
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
18 */
19 #include <linux/init.h>
20 #include <linux/pci.h>
22 #include <asm/mips-boards/atlasint.h>
24 #define PCIA ATLASINT_PCIA
25 #define PCIB ATLASINT_PCIB
26 #define PCIC ATLASINT_PCIC
27 #define PCID ATLASINT_PCID
28 #define INTA ATLASINT_INTA
29 #define INTB ATLASINT_INTB
30 #define ETH ATLASINT_ETH
31 #define INTC ATLASINT_INTC
32 #define SCSI ATLASINT_SCSI
33 #define INTD ATLASINT_INTD
35 static char irq_tab[][5] __initdata = {
36 /* INTA INTB INTC INTD */
37 {0, 0, 0, 0, 0 }, /* 0: Unused */
38 {0, 0, 0, 0, 0 }, /* 1: Unused */
39 {0, 0, 0, 0, 0 }, /* 2: Unused */
40 {0, 0, 0, 0, 0 }, /* 3: Unused */
41 {0, 0, 0, 0, 0 }, /* 4: Unused */
42 {0, 0, 0, 0, 0 }, /* 5: Unused */
43 {0, 0, 0, 0, 0 }, /* 6: Unused */
44 {0, 0, 0, 0, 0 }, /* 7: Unused */
45 {0, 0, 0, 0, 0 }, /* 8: Unused */
46 {0, 0, 0, 0, 0 }, /* 9: Unused */
47 {0, 0, 0, 0, 0 }, /* 10: Unused */
48 {0, 0, 0, 0, 0 }, /* 11: Unused */
49 {0, 0, 0, 0, 0 }, /* 12: Unused */
50 {0, 0, 0, 0, 0 }, /* 13: Unused */
51 {0, 0, 0, 0, 0 }, /* 14: Unused */
52 {0, PCIA, PCIB, PCIC, PCID }, /* 15: cPCI (behind 21150) */
53 {0, SCSI, 0, 0, 0 }, /* 16: SYM53C810A SCSI */
54 {0, 0, 0, 0, 0 }, /* 17: Core */
55 {0, INTA, INTB, INTC, INTD }, /* 18: PCI Slot */
56 {0, ETH, 0, 0, 0 }, /* 19: SAA9730 Eth. et al. */
57 {0, 0, 0, 0, 0 }, /* 20: Unused */
58 {0, 0, 0, 0, 0 } /* 21: Unused */
59 };
61 int __init pcibios_map_irq(struct pci_dev *dev, u8 slot, u8 pin)
62 {
63 return irq_tab[slot][pin];
64 }
66 /* Do platform specific device initialization at pci_enable_device() time */
67 int pcibios_plat_dev_init(struct pci_dev *dev)
68 {
69 return 0;
70 }
72 #ifdef CONFIG_KGDB
73 /*
74 * The PCI scan may have moved the saa9730 I/O address, so reread
75 * the address here.
76 * This does mean that it's not possible to debug the PCI bus configuration
77 * code, but it is better than nothing...
78 */
80 static void atlas_saa9730_base_fixup (struct pci_dev *pdev)
81 {
82 extern void *saa9730_base;
83 if (pdev->bus == 0 && PCI_SLOT(pdev->devfn) == 19)
84 (void) pci_read_config_dword (pdev, 0x14, (u32 *)&saa9730_base);
85 printk ("saa9730_base = %x\n", saa9730_base);
86 }
88 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_PHILIPS, PCI_DEVICE_ID_PHILIPS_SAA9730,
89 atlas_saa9730_base_fixup);
91 #endif