ia64/linux-2.6.18-xen.hg

view arch/mips/sgi-ip32/crime.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 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 2001, 2003 Keith M Wesolowski
7 * Copyright (C) 2005 Ilya A. Volynets <ilya@total-knowledge.com>
8 */
9 #include <linux/types.h>
10 #include <linux/init.h>
11 #include <linux/kernel.h>
12 #include <linux/interrupt.h>
13 #include <linux/module.h>
14 #include <asm/bootinfo.h>
15 #include <asm/io.h>
16 #include <asm/mipsregs.h>
17 #include <asm/ptrace.h>
18 #include <asm/page.h>
19 #include <asm/ip32/crime.h>
20 #include <asm/ip32/mace.h>
22 struct sgi_crime __iomem *crime;
23 struct sgi_mace __iomem *mace;
25 EXPORT_SYMBOL_GPL(mace);
27 void __init crime_init(void)
28 {
29 unsigned int id, rev;
30 const int field = 2 * sizeof(unsigned long);
32 set_io_port_base((unsigned long) ioremap(MACEPCI_LOW_IO, 0x2000000));
33 crime = ioremap(CRIME_BASE, sizeof(struct sgi_crime));
34 mace = ioremap(MACE_BASE, sizeof(struct sgi_mace));
36 id = crime->id;
37 rev = id & CRIME_ID_REV;
38 id = (id & CRIME_ID_IDBITS) >> 4;
39 printk (KERN_INFO "CRIME id %1x rev %d at 0x%0*lx\n",
40 id, rev, field, (unsigned long) CRIME_BASE);
41 }
43 irqreturn_t
44 crime_memerr_intr (unsigned int irq, void *dev_id, struct pt_regs *regs)
45 {
46 unsigned long stat, addr;
47 int fatal = 0;
49 stat = crime->mem_error_stat & CRIME_MEM_ERROR_STAT_MASK;
50 addr = crime->mem_error_addr & CRIME_MEM_ERROR_ADDR_MASK;
52 printk("CRIME memory error at 0x%08lx ST 0x%08lx<", addr, stat);
54 if (stat & CRIME_MEM_ERROR_INV)
55 printk("INV,");
56 if (stat & CRIME_MEM_ERROR_ECC) {
57 unsigned long ecc_syn =
58 crime->mem_ecc_syn & CRIME_MEM_ERROR_ECC_SYN_MASK;
59 unsigned long ecc_gen =
60 crime->mem_ecc_chk & CRIME_MEM_ERROR_ECC_CHK_MASK;
61 printk("ECC,SYN=0x%08lx,GEN=0x%08lx,", ecc_syn, ecc_gen);
62 }
63 if (stat & CRIME_MEM_ERROR_MULTIPLE) {
64 fatal = 1;
65 printk("MULTIPLE,");
66 }
67 if (stat & CRIME_MEM_ERROR_HARD_ERR) {
68 fatal = 1;
69 printk("HARD,");
70 }
71 if (stat & CRIME_MEM_ERROR_SOFT_ERR)
72 printk("SOFT,");
73 if (stat & CRIME_MEM_ERROR_CPU_ACCESS)
74 printk("CPU,");
75 if (stat & CRIME_MEM_ERROR_VICE_ACCESS)
76 printk("VICE,");
77 if (stat & CRIME_MEM_ERROR_GBE_ACCESS)
78 printk("GBE,");
79 if (stat & CRIME_MEM_ERROR_RE_ACCESS)
80 printk("RE,REID=0x%02lx,", (stat & CRIME_MEM_ERROR_RE_ID)>>8);
81 if (stat & CRIME_MEM_ERROR_MACE_ACCESS)
82 printk("MACE,MACEID=0x%02lx,", stat & CRIME_MEM_ERROR_MACE_ID);
84 crime->mem_error_stat = 0;
86 if (fatal) {
87 printk("FATAL>\n");
88 panic("Fatal memory error.");
89 } else
90 printk("NONFATAL>\n");
92 return IRQ_HANDLED;
93 }
95 irqreturn_t
96 crime_cpuerr_intr (unsigned int irq, void *dev_id, struct pt_regs *regs)
97 {
98 unsigned long stat = crime->cpu_error_stat & CRIME_CPU_ERROR_MASK;
99 unsigned long addr = crime->cpu_error_addr & CRIME_CPU_ERROR_ADDR_MASK;
101 addr <<= 2;
102 printk ("CRIME CPU error at 0x%09lx status 0x%08lx\n", addr, stat);
103 crime->cpu_error_stat = 0;
105 return IRQ_HANDLED;
106 }