ia64/linux-2.6.18-xen.hg

view arch/mips/pci/pci-excite.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) 2004 by Basler Vision Technologies AG
3 * Author: Thomas Koeller <thomas.koeller@baslerweb.com>
4 * Based on the PMC-Sierra Yosemite board support by Ralf Baechle.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 */
20 #include <linux/init.h>
21 #include <linux/kernel.h>
22 #include <linux/types.h>
23 #include <linux/pci.h>
24 #include <linux/bitops.h>
25 #include <asm/rm9k-ocd.h>
26 #include <excite.h>
29 extern struct pci_ops titan_pci_ops;
32 static struct resource
33 mem_resource = {
34 .name = "PCI memory",
35 .start = EXCITE_PHYS_PCI_MEM,
36 .end = EXCITE_PHYS_PCI_MEM + EXCITE_SIZE_PCI_MEM - 1,
37 .flags = IORESOURCE_MEM
38 },
39 io_resource = {
40 .name = "PCI I/O",
41 .start = EXCITE_PHYS_PCI_IO,
42 .end = EXCITE_PHYS_PCI_IO + EXCITE_SIZE_PCI_IO - 1,
43 .flags = IORESOURCE_IO
44 };
47 static struct pci_controller bx_controller = {
48 .pci_ops = &titan_pci_ops,
49 .mem_resource = &mem_resource,
50 .mem_offset = 0x00000000UL,
51 .io_resource = &io_resource,
52 .io_offset = 0x00000000UL
53 };
56 static char
57 iopage_failed[] __initdata = "Cannot allocate PCI I/O page",
58 modebits_no_pci[] __initdata = "PCI is not configured in mode bits";
60 #define RM9000x2_OCD_HTSC 0x0604
61 #define RM9000x2_OCD_HTBHL 0x060c
62 #define RM9000x2_OCD_PCIHRST 0x078c
64 #define RM9K_OCD_MODEBIT1 0x00d4 /* (MODEBIT1) Mode Bit 1 */
65 #define RM9K_OCD_CPHDCR 0x00f4 /* CPU-PCI/HT Data Control. */
67 #define PCISC_FB2B 0x00000200
68 #define PCISC_MWICG 0x00000010
69 #define PCISC_EMC 0x00000004
70 #define PCISC_ERMA 0x00000002
74 static int __init basler_excite_pci_setup(void)
75 {
76 const unsigned int fullbars = memsize / (256 << 20);
77 unsigned int i;
79 /* Check modebits to see if PCI is really enabled. */
80 if (!((ocd_readl(RM9K_OCD_MODEBIT1) >> (47-32)) & 0x1))
81 panic(modebits_no_pci);
83 if (NULL == request_mem_region(EXCITE_PHYS_PCI_IO, EXCITE_SIZE_PCI_IO,
84 "Memory-mapped PCI I/O page"))
85 panic(iopage_failed);
87 /* Enable PCI 0 as master for config cycles */
88 ocd_writel(PCISC_EMC | PCISC_ERMA, RM9000x2_OCD_HTSC);
91 /* Set up latency timer */
92 ocd_writel(0x8008, RM9000x2_OCD_HTBHL);
94 /* Setup host IO and Memory space */
95 ocd_writel((EXCITE_PHYS_PCI_IO >> 4) | 1, LKB7);
96 ocd_writel(((EXCITE_SIZE_PCI_IO >> 4) & 0x7fffff00) - 0x100, LKM7);
97 ocd_writel((EXCITE_PHYS_PCI_MEM >> 4) | 1, LKB8);
98 ocd_writel(((EXCITE_SIZE_PCI_MEM >> 4) & 0x7fffff00) - 0x100, LKM8);
100 /* Set up PCI BARs to map all installed memory */
101 for (i = 0; i < 6; i++) {
102 const unsigned int bar = 0x610 + i * 4;
104 if (i < fullbars) {
105 ocd_writel(0x10000000 * i, bar);
106 ocd_writel(0x01000000 * i, bar + 0x140);
107 ocd_writel(0x0ffff029, bar + 0x100);
108 continue;
109 }
111 if (i == fullbars) {
112 int o;
113 u32 mask;
115 const unsigned long rem = memsize - i * 0x10000000;
116 if (!rem) {
117 ocd_writel(0x00000000, bar + 0x100);
118 continue;
119 }
121 o = ffs(rem) - 1;
122 if (rem & ~(0x1 << o))
123 o++;
124 mask = ((0x1 << o) & 0x0ffff000) - 0x1000;
125 ocd_writel(0x10000000 * i, bar);
126 ocd_writel(0x01000000 * i, bar + 0x140);
127 ocd_writel(0x00000029 | mask, bar + 0x100);
128 continue;
129 }
131 ocd_writel(0x00000000, bar + 0x100);
132 }
134 /* Finally, enable the PCI interupt */
135 #if USB_IRQ > 7
136 set_c0_intcontrol(1 << USB_IRQ);
137 #else
138 set_c0_status(1 << (USB_IRQ + 8));
139 #endif
141 ioport_resource.start = EXCITE_PHYS_PCI_IO;
142 ioport_resource.end = EXCITE_PHYS_PCI_IO + EXCITE_SIZE_PCI_IO - 1;
143 set_io_port_base((unsigned long) ioremap_nocache(EXCITE_PHYS_PCI_IO, EXCITE_SIZE_PCI_IO));
144 register_pci_controller(&bx_controller);
145 return 0;
146 }
149 arch_initcall(basler_excite_pci_setup);