ia64/linux-2.6.18-xen.hg

view drivers/mtd/chips/cfi_util.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 * Common Flash Interface support:
3 * Generic utility functions not dependant on command set
4 *
5 * Copyright (C) 2002 Red Hat
6 * Copyright (C) 2003 STMicroelectronics Limited
7 *
8 * This code is covered by the GPL.
9 *
10 * $Id: cfi_util.c,v 1.10 2005/11/07 11:14:23 gleixner Exp $
11 *
12 */
14 #include <linux/module.h>
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/sched.h>
18 #include <asm/io.h>
19 #include <asm/byteorder.h>
21 #include <linux/errno.h>
22 #include <linux/slab.h>
23 #include <linux/delay.h>
24 #include <linux/interrupt.h>
25 #include <linux/mtd/xip.h>
26 #include <linux/mtd/mtd.h>
27 #include <linux/mtd/map.h>
28 #include <linux/mtd/cfi.h>
29 #include <linux/mtd/compatmac.h>
31 struct cfi_extquery *
32 __xipram cfi_read_pri(struct map_info *map, __u16 adr, __u16 size, const char* name)
33 {
34 struct cfi_private *cfi = map->fldrv_priv;
35 __u32 base = 0; // cfi->chips[0].start;
36 int ofs_factor = cfi->interleave * cfi->device_type;
37 int i;
38 struct cfi_extquery *extp = NULL;
40 printk(" %s Extended Query Table at 0x%4.4X\n", name, adr);
41 if (!adr)
42 goto out;
44 extp = kmalloc(size, GFP_KERNEL);
45 if (!extp) {
46 printk(KERN_ERR "Failed to allocate memory\n");
47 goto out;
48 }
50 #ifdef CONFIG_MTD_XIP
51 local_irq_disable();
52 #endif
54 /* Switch it into Query Mode */
55 cfi_send_gen_cmd(0x98, 0x55, base, map, cfi, cfi->device_type, NULL);
57 /* Read in the Extended Query Table */
58 for (i=0; i<size; i++) {
59 ((unsigned char *)extp)[i] =
60 cfi_read_query(map, base+((adr+i)*ofs_factor));
61 }
63 /* Make sure it returns to read mode */
64 cfi_send_gen_cmd(0xf0, 0, base, map, cfi, cfi->device_type, NULL);
65 cfi_send_gen_cmd(0xff, 0, base, map, cfi, cfi->device_type, NULL);
67 #ifdef CONFIG_MTD_XIP
68 (void) map_read(map, base);
69 asm volatile (".rep 8; nop; .endr");
70 local_irq_enable();
71 #endif
73 out: return extp;
74 }
76 EXPORT_SYMBOL(cfi_read_pri);
78 void cfi_fixup(struct mtd_info *mtd, struct cfi_fixup *fixups)
79 {
80 struct map_info *map = mtd->priv;
81 struct cfi_private *cfi = map->fldrv_priv;
82 struct cfi_fixup *f;
84 for (f=fixups; f->fixup; f++) {
85 if (((f->mfr == CFI_MFR_ANY) || (f->mfr == cfi->mfr)) &&
86 ((f->id == CFI_ID_ANY) || (f->id == cfi->id))) {
87 f->fixup(mtd, f->param);
88 }
89 }
90 }
92 EXPORT_SYMBOL(cfi_fixup);
94 int cfi_varsize_frob(struct mtd_info *mtd, varsize_frob_t frob,
95 loff_t ofs, size_t len, void *thunk)
96 {
97 struct map_info *map = mtd->priv;
98 struct cfi_private *cfi = map->fldrv_priv;
99 unsigned long adr;
100 int chipnum, ret = 0;
101 int i, first;
102 struct mtd_erase_region_info *regions = mtd->eraseregions;
104 if (ofs > mtd->size)
105 return -EINVAL;
107 if ((len + ofs) > mtd->size)
108 return -EINVAL;
110 /* Check that both start and end of the requested erase are
111 * aligned with the erasesize at the appropriate addresses.
112 */
114 i = 0;
116 /* Skip all erase regions which are ended before the start of
117 the requested erase. Actually, to save on the calculations,
118 we skip to the first erase region which starts after the
119 start of the requested erase, and then go back one.
120 */
122 while (i < mtd->numeraseregions && ofs >= regions[i].offset)
123 i++;
124 i--;
126 /* OK, now i is pointing at the erase region in which this
127 erase request starts. Check the start of the requested
128 erase range is aligned with the erase size which is in
129 effect here.
130 */
132 if (ofs & (regions[i].erasesize-1))
133 return -EINVAL;
135 /* Remember the erase region we start on */
136 first = i;
138 /* Next, check that the end of the requested erase is aligned
139 * with the erase region at that address.
140 */
142 while (i<mtd->numeraseregions && (ofs + len) >= regions[i].offset)
143 i++;
145 /* As before, drop back one to point at the region in which
146 the address actually falls
147 */
148 i--;
150 if ((ofs + len) & (regions[i].erasesize-1))
151 return -EINVAL;
153 chipnum = ofs >> cfi->chipshift;
154 adr = ofs - (chipnum << cfi->chipshift);
156 i=first;
158 while(len) {
159 int size = regions[i].erasesize;
161 ret = (*frob)(map, &cfi->chips[chipnum], adr, size, thunk);
163 if (ret)
164 return ret;
166 adr += size;
167 ofs += size;
168 len -= size;
170 if (ofs == regions[i].offset + size * regions[i].numblocks)
171 i++;
173 if (adr >> cfi->chipshift) {
174 adr = 0;
175 chipnum++;
177 if (chipnum >= cfi->numchips)
178 break;
179 }
180 }
182 return 0;
183 }
185 EXPORT_SYMBOL(cfi_varsize_frob);
187 MODULE_LICENSE("GPL");