ia64/linux-2.6.18-xen.hg

view drivers/mtd/maps/h720x-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 * Flash memory access on Hynix GMS30C7201/HMS30C7202 based
3 * evaluation boards
4 *
5 * $Id: h720x-flash.c,v 1.12 2005/11/07 11:14:27 gleixner Exp $
6 *
7 * (C) 2002 Jungjun Kim <jungjun.kim@hynix.com>
8 * 2003 Thomas Gleixner <tglx@linutronix.de>
9 */
11 #include <linux/module.h>
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/init.h>
15 #include <linux/errno.h>
16 #include <linux/slab.h>
18 #include <linux/mtd/mtd.h>
19 #include <linux/mtd/map.h>
20 #include <linux/mtd/partitions.h>
21 #include <asm/hardware.h>
22 #include <asm/io.h>
24 static struct mtd_info *mymtd;
26 static struct map_info h720x_map = {
27 .name = "H720X",
28 .bankwidth = 4,
29 .size = FLASH_SIZE,
30 .phys = FLASH_PHYS,
31 };
33 static struct mtd_partition h720x_partitions[] = {
34 {
35 .name = "ArMon",
36 .size = 0x00080000,
37 .offset = 0,
38 .mask_flags = MTD_WRITEABLE
39 },{
40 .name = "Env",
41 .size = 0x00040000,
42 .offset = 0x00080000,
43 .mask_flags = MTD_WRITEABLE
44 },{
45 .name = "Kernel",
46 .size = 0x00180000,
47 .offset = 0x000c0000,
48 .mask_flags = MTD_WRITEABLE
49 },{
50 .name = "Ramdisk",
51 .size = 0x00400000,
52 .offset = 0x00240000,
53 .mask_flags = MTD_WRITEABLE
54 },{
55 .name = "jffs2",
56 .size = MTDPART_SIZ_FULL,
57 .offset = MTDPART_OFS_APPEND
58 }
59 };
61 #define NUM_PARTITIONS ARRAY_SIZE(h720x_partitions)
63 static int nr_mtd_parts;
64 static struct mtd_partition *mtd_parts;
65 static const char *probes[] = { "cmdlinepart", NULL };
67 /*
68 * Initialize FLASH support
69 */
70 int __init h720x_mtd_init(void)
71 {
73 char *part_type = NULL;
75 h720x_map.virt = ioremap(FLASH_PHYS, FLASH_SIZE);
77 if (!h720x_map.virt) {
78 printk(KERN_ERR "H720x-MTD: ioremap failed\n");
79 return -EIO;
80 }
82 simple_map_init(&h720x_map);
84 // Probe for flash bankwidth 4
85 printk (KERN_INFO "H720x-MTD probing 32bit FLASH\n");
86 mymtd = do_map_probe("cfi_probe", &h720x_map);
87 if (!mymtd) {
88 printk (KERN_INFO "H720x-MTD probing 16bit FLASH\n");
89 // Probe for bankwidth 2
90 h720x_map.bankwidth = 2;
91 mymtd = do_map_probe("cfi_probe", &h720x_map);
92 }
94 if (mymtd) {
95 mymtd->owner = THIS_MODULE;
97 #ifdef CONFIG_MTD_PARTITIONS
98 nr_mtd_parts = parse_mtd_partitions(mymtd, probes, &mtd_parts, 0);
99 if (nr_mtd_parts > 0)
100 part_type = "command line";
101 #endif
102 if (nr_mtd_parts <= 0) {
103 mtd_parts = h720x_partitions;
104 nr_mtd_parts = NUM_PARTITIONS;
105 part_type = "builtin";
106 }
107 printk(KERN_INFO "Using %s partition table\n", part_type);
108 add_mtd_partitions(mymtd, mtd_parts, nr_mtd_parts);
109 return 0;
110 }
112 iounmap((void *)h720x_map.virt);
113 return -ENXIO;
114 }
116 /*
117 * Cleanup
118 */
119 static void __exit h720x_mtd_cleanup(void)
120 {
122 if (mymtd) {
123 del_mtd_partitions(mymtd);
124 map_destroy(mymtd);
125 }
127 /* Free partition info, if commandline partition was used */
128 if (mtd_parts && (mtd_parts != h720x_partitions))
129 kfree (mtd_parts);
131 if (h720x_map.virt) {
132 iounmap((void *)h720x_map.virt);
133 h720x_map.virt = 0;
134 }
135 }
138 module_init(h720x_mtd_init);
139 module_exit(h720x_mtd_cleanup);
141 MODULE_LICENSE("GPL");
142 MODULE_AUTHOR("Thomas Gleixner <tglx@linutronix.de>");
143 MODULE_DESCRIPTION("MTD map driver for Hynix evaluation boards");