ia64/linux-2.6.18-xen.hg

view drivers/mtd/maps/sharpsl-flash.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 * sharpsl-flash.c
3 *
4 * Copyright (C) 2001 Lineo Japan, Inc.
5 * Copyright (C) 2002 SHARP
6 *
7 * $Id: sharpsl-flash.c,v 1.7 2005/11/07 11:14:28 gleixner Exp $
8 *
9 * based on rpxlite.c,v 1.15 2001/10/02 15:05:14 dwmw2 Exp
10 * Handle mapping of the flash on the RPX Lite and CLLF boards
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
21 *
22 */
24 #include <linux/module.h>
25 #include <linux/types.h>
26 #include <linux/kernel.h>
27 #include <linux/mtd/mtd.h>
28 #include <linux/mtd/map.h>
29 #include <linux/mtd/partitions.h>
30 #include <asm/io.h>
31 #include <asm/mach-types.h>
33 #define WINDOW_ADDR 0x00000000
34 #define WINDOW_SIZE 0x00800000
35 #define BANK_WIDTH 2
37 static struct mtd_info *mymtd;
39 struct map_info sharpsl_map = {
40 .name = "sharpsl-flash",
41 .size = WINDOW_SIZE,
42 .bankwidth = BANK_WIDTH,
43 .phys = WINDOW_ADDR
44 };
46 static struct mtd_partition sharpsl_partitions[1] = {
47 {
48 name: "Boot PROM Filesystem",
49 }
50 };
52 int __init init_sharpsl(void)
53 {
54 struct mtd_partition *parts;
55 int nb_parts = 0;
56 char *part_type = "static";
58 printk(KERN_NOTICE "Sharp SL series flash device: %x at %x\n",
59 WINDOW_SIZE, WINDOW_ADDR);
60 sharpsl_map.virt = ioremap(WINDOW_ADDR, WINDOW_SIZE);
61 if (!sharpsl_map.virt) {
62 printk("Failed to ioremap\n");
63 return -EIO;
64 }
66 simple_map_init(&sharpsl_map);
68 mymtd = do_map_probe("map_rom", &sharpsl_map);
69 if (!mymtd) {
70 iounmap(sharpsl_map.virt);
71 return -ENXIO;
72 }
74 mymtd->owner = THIS_MODULE;
76 if (machine_is_corgi() || machine_is_shepherd() || machine_is_husky()
77 || machine_is_poodle()) {
78 sharpsl_partitions[0].size=0x006d0000;
79 sharpsl_partitions[0].offset=0x00120000;
80 } else if (machine_is_tosa()) {
81 sharpsl_partitions[0].size=0x006a0000;
82 sharpsl_partitions[0].offset=0x00160000;
83 } else if (machine_is_spitz() || machine_is_akita() || machine_is_borzoi()) {
84 sharpsl_partitions[0].size=0x006b0000;
85 sharpsl_partitions[0].offset=0x00140000;
86 } else {
87 map_destroy(mymtd);
88 iounmap(sharpsl_map.virt);
89 return -ENODEV;
90 }
92 parts = sharpsl_partitions;
93 nb_parts = ARRAY_SIZE(sharpsl_partitions);
95 printk(KERN_NOTICE "Using %s partision definition\n", part_type);
96 add_mtd_partitions(mymtd, parts, nb_parts);
98 return 0;
99 }
101 static void __exit cleanup_sharpsl(void)
102 {
103 if (mymtd) {
104 del_mtd_partitions(mymtd);
105 map_destroy(mymtd);
106 }
107 if (sharpsl_map.virt) {
108 iounmap(sharpsl_map.virt);
109 sharpsl_map.virt = 0;
110 }
111 }
113 module_init(init_sharpsl);
114 module_exit(cleanup_sharpsl);
116 MODULE_LICENSE("GPL");
117 MODULE_AUTHOR("SHARP (Original: Arnold Christensen <AKC@pel.dk>)");
118 MODULE_DESCRIPTION("MTD map driver for SHARP SL series");