ia64/linux-2.6.18-xen.hg

view drivers/mtd/maps/dbox2-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 * $Id: dbox2-flash.c,v 1.14 2005/11/07 11:14:26 gleixner Exp $
3 *
4 * D-Box 2 flash driver
5 */
7 #include <linux/module.h>
8 #include <linux/types.h>
9 #include <linux/kernel.h>
10 #include <linux/init.h>
11 #include <asm/io.h>
12 #include <linux/mtd/mtd.h>
13 #include <linux/mtd/map.h>
14 #include <linux/mtd/partitions.h>
15 #include <linux/errno.h>
17 /* partition_info gives details on the logical partitions that the split the
18 * single flash device into. If the size if zero we use up to the end of the
19 * device. */
20 static struct mtd_partition partition_info[]= {
21 {
22 .name = "BR bootloader",
23 .size = 128 * 1024,
24 .offset = 0,
25 .mask_flags = MTD_WRITEABLE
26 },
27 {
28 .name = "FLFS (U-Boot)",
29 .size = 128 * 1024,
30 .offset = MTDPART_OFS_APPEND,
31 .mask_flags = 0
32 },
33 {
34 .name = "Root (SquashFS)",
35 .size = 7040 * 1024,
36 .offset = MTDPART_OFS_APPEND,
37 .mask_flags = 0
38 },
39 {
40 .name = "var (JFFS2)",
41 .size = 896 * 1024,
42 .offset = MTDPART_OFS_APPEND,
43 .mask_flags = 0
44 },
45 {
46 .name = "Flash without bootloader",
47 .size = MTDPART_SIZ_FULL,
48 .offset = 128 * 1024,
49 .mask_flags = 0
50 },
51 {
52 .name = "Complete Flash",
53 .size = MTDPART_SIZ_FULL,
54 .offset = 0,
55 .mask_flags = MTD_WRITEABLE
56 }
57 };
59 #define NUM_PARTITIONS ARRAY_SIZE(partition_info)
61 #define WINDOW_ADDR 0x10000000
62 #define WINDOW_SIZE 0x800000
64 static struct mtd_info *mymtd;
67 struct map_info dbox2_flash_map = {
68 .name = "D-Box 2 flash memory",
69 .size = WINDOW_SIZE,
70 .bankwidth = 4,
71 .phys = WINDOW_ADDR,
72 };
74 int __init init_dbox2_flash(void)
75 {
76 printk(KERN_NOTICE "D-Box 2 flash driver (size->0x%X mem->0x%X)\n", WINDOW_SIZE, WINDOW_ADDR);
77 dbox2_flash_map.virt = ioremap(WINDOW_ADDR, WINDOW_SIZE);
79 if (!dbox2_flash_map.virt) {
80 printk("Failed to ioremap\n");
81 return -EIO;
82 }
83 simple_map_init(&dbox2_flash_map);
85 // Probe for dual Intel 28F320 or dual AMD
86 mymtd = do_map_probe("cfi_probe", &dbox2_flash_map);
87 if (!mymtd) {
88 // Probe for single Intel 28F640
89 dbox2_flash_map.bankwidth = 2;
91 mymtd = do_map_probe("cfi_probe", &dbox2_flash_map);
92 }
94 if (mymtd) {
95 mymtd->owner = THIS_MODULE;
97 /* Create MTD devices for each partition. */
98 add_mtd_partitions(mymtd, partition_info, NUM_PARTITIONS);
100 return 0;
101 }
103 iounmap((void *)dbox2_flash_map.virt);
104 return -ENXIO;
105 }
107 static void __exit cleanup_dbox2_flash(void)
108 {
109 if (mymtd) {
110 del_mtd_partitions(mymtd);
111 map_destroy(mymtd);
112 }
113 if (dbox2_flash_map.virt) {
114 iounmap((void *)dbox2_flash_map.virt);
115 dbox2_flash_map.virt = 0;
116 }
117 }
119 module_init(init_dbox2_flash);
120 module_exit(cleanup_dbox2_flash);
123 MODULE_LICENSE("GPL");
124 MODULE_AUTHOR("Kári Davíðsson <kd@flaga.is>, Bastian Blank <waldi@tuxbox.org>, Alexander Wild <wild@te-elektronik.com>");
125 MODULE_DESCRIPTION("MTD map driver for D-Box 2 board");