aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/video/atafb_iplan2p8.c
blob: 356fb52ce44307410be7dc20dfab0c50a79c5d3e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
/*
 *  linux/drivers/video/iplan2p8.c -- Low level frame buffer operations for
 *				      interleaved bitplanes à la Atari (8
 *				      planes, 2 bytes interleave)
 *
 *	Created 5 Apr 1997 by Geert Uytterhoeven
 *
 *  This file is subject to the terms and conditions of the GNU General Public
 *  License.  See the file COPYING in the main directory of this archive for
 *  more details.
 */

#include <linux/module.h>
#include <linux/string.h>
#include <linux/fb.h>

#include <asm/setup.h>

#include "atafb.h"

#define BPL	8
#include "atafb_utils.h"


/* Copies a 8 plane column from 's', height 'h', to 'd'. */

/* This expands a 8 bit color into two longs for two movepl (8 plane)
 * operations.
 */

void atafb_iplan2p8_copyarea(struct fb_info *info, u_long next_line,
			     int sy, int sx, int dy, int dx,
			     int height, int width)
{
	/*  bmove() has to distinguish two major cases: If both, source and
	 *  destination, start at even addresses or both are at odd
	 *  addresses, just the first odd and last even column (if present)
	 *  require special treatment (memmove_col()). The rest between
	 *  then can be copied by normal operations, because all adjacent
	 *  bytes are affected and are to be stored in the same order.
	 *    The pathological case is when the move should go from an odd
	 *  address to an even or vice versa. Since the bytes in the plane
	 *  words must be assembled in new order, it seems wisest to make
	 *  all movements by memmove_col().
	 */

	u8 *src, *dst;
	u32 *s, *d;
	int w, l , i, j;
	u_int colsize;
	u_int upwards = (dy < sy) || (dy == sy && dx < sx);

	colsize = height;
	if (!((sx ^ dx) & 15)) {
		/* odd->odd or even->even */

		if (upwards) {
			src = (u8 *)info->screen_base + sy * next_line + (sx & ~15) / (8 / BPL);
			dst = (u8 *)info->screen_base + dy * next_line + (dx & ~15) / (8 / BPL);
			if (sx & 15) {
				memmove32_col(dst, src, 0xff00ff, height, next_line - BPL * 2);
				src += BPL * 2;
				dst += BPL * 2;
				width -= 8;
			}
			w = width >> 4;
			if (w) {
				s = (u32 *)src;
				d = (u32 *)dst;
				w *= BPL / 2;
				l = next_line - w * 4;
				for (j = height; j > 0; j--) {
					for (i = w; i > 0; i--)
						*d++ = *s++;
					s = (u32 *)((u8 *)s + l);
					d = (u32 *)((u8 *)d + l);
				}
			}
			if (width & 15)
				memmove32_col(dst + width / (8 / BPL), src + width / (8 / BPL),
					      0xff00ff00, height, next_line - BPL * 2);
		} else {
			src = (u8 *)info->screen_base + (sy - 1) * next_line + ((sx + width + 8) & ~15) / (8 / BPL);
			dst = (u8 *)info->screen_base + (dy - 1) * next_line + ((dx + width + 8) & ~15) / (8 / BPL);

			if ((sx + width) & 15) {
				src -= BPL * 2;
				dst -= BPL * 2;
				memmove32_col(dst, src, 0xff00ff00, colsize, -next_line - BPL * 2);
				width -= 8;
			}
			w = width >> 4;
			if (w) {
				s = (u32 *)src;
				d = (u32 *)dst;
				w *= BPL / 2;
				l = next_line - w * 4;
				for (j = height; j > 0; j--) {
					for (i = w; i > 0; i--)
						*--d = *--s;
					s = (u32 *)((u8 *)s - l);
					d = (u32 *)((u8 *)d - l);
				}
			}
			if (sx & 15)
				memmove32_col(dst - (width - 16) / (8 / BPL),
					      src - (width - 16) / (8 / BPL),
					      0xff00ff, colsize, -next_line - BPL * 2);
		}
	} else {
		/* odd->even or even->odd */
		if (upwards) {
			u32 *src32, *dst32;
			u32 pval[4], v, v1, mask;
			int i, j, w, f;

			src = (u8 *)info->screen_base + sy * next_line + (sx & ~15) / (8 / BPL);
			dst = (u8 *)info->screen_base + dy * next_line + (dx & ~15) / (8 / BPL);

			mask = 0xff00ff00;
			f = 0;
			w = width;
			if (sx & 15) {
				f = 1;
				w += 8;
			}
			if ((sx + width) & 15)
				f |= 2;
			w >>= 4;
			for (i = height; i; i--) {
				src32 = (u32 *)src;
				dst32 = (u32 *)dst;

				if (f & 1) {
					pval[0] = (*src32++ << 8) & mask;
					pval[1] = (*src32++ << 8) & mask;
					pval[2] = (*src32++ << 8) & mask;
					pval[3] = (*src32++ << 8) & mask;
				} else {
					pval[0] = dst32[0] & mask;
					pval[1] = dst32[1] & mask;
					pval[2] = dst32[2] & mask;
					pval[3] = dst32[3] & mask;
				}

				for (j = w; j > 0; j--) {
					v = *src32++;
					v1 = v & mask;
					*dst32++ = pval[0] | (v1 >> 8);
					pval[0] = (v ^ v1) << 8;
					v = *src32++;
					v1 = v & mask;
					*dst32++ = pval[1] | (v1 >> 8);
					pval[1] = (v ^ v1) << 8;
					v = *src32++;
					v1 = v & mask;
					*dst32++ = pval[2] | (v1 >> 8);
					pval[2] = (v ^ v1) << 8;
					v = *src32++;
					v1 = v & mask;
					*dst32++ = pval[3] | (v1 >> 8);
					pval[3] = (v ^ v1) << 8;
				}

				if (f & 2) {
					dst32[0] = (dst32[0] & mask) | pval[0];
					dst32[1] = (dst32[1] & mask) | pval[1];
					dst32[2] = (dst32[2] & mask) | pval[2];
					dst32[3] = (dst32[3] & mask) | pval[3];
				}

				src += next_line;
				dst += next_line;
			}
		} else {
			u32 *src32, *dst32;
			u32 pval[4], v, v1, mask;
			int i, j, w, f;

			src = (u8 *)info->screen_base + (sy - 1) * next_line + ((sx + width + 8) & ~15) / (8 / BPL);
			dst = (u8 *)info->screen_base + (dy - 1) * next_line + ((dx + width + 8) & ~15) / (8 / BPL);

			mask = 0xff00ff;
			f = 0;
			w = width;
			if ((dx + width) & 15)
				f = 1;
			if (sx & 15) {
				f |= 2;
				w += 8;
			}
			w >>= 4;
			for (i = height; i; i--) {
				src32 = (u32 *)src;
				dst32 = (u32 *)dst;

				if (f & 1) {
					pval[0] = dst32[-1] & mask;
					pval[1] = dst32[-2] & mask;
					pval[2] = dst32[-3] & mask;
					pval[3] = dst32[-4] & mask;
				} else {
					pval[0] = (*--src32 >> 8) & mask;
					pval[1] = (*--src32 >> 8) & mask;
					pval[2] = (*--src32 >> 8) & mask;
					pval[3] = (*--src32 >> 8) & mask;
				}

				for (j = w; j > 0; j--) {
					v = *--src32;
					v1 = v & mask;
					*--dst32 = pval[0] | (v1 << 8);
					pval[0] = (v ^ v1) >> 8;
					v = *--src32;
					v1 = v & mask;
					*--dst32 = pval[1] | (v1 << 8);
					pval[1] = (v ^ v1) >> 8;
					v = *--src32;
					v1 = v & mask;
					*--dst32 = pval[2] | (v1 << 8);
					pval[2] = (v ^ v1) >> 8;
					v = *--src32;
					v1 = v & mask;
					*--dst32 = pval[3] | (v1 << 8);
					pval[3] = (v ^ v1) >> 8;
				}

				if (!(f & 2)) {
					dst32[-1] = (dst32[-1] & mask) | pval[0];
					dst32[-2] = (dst32[-2] & mask) | pval[1];
					dst32[-3] = (dst32[-3] & mask) | pval[2];
					dst32[-4] = (dst32[-4] & mask) | pval[3];
				}

				src -= next_line;
				dst -= next_line;
			}
		}
	}
}

void atafb_iplan2p8_fillrect(struct fb_info *info, u_long next_line, u32 color,
                             int sy, int sx, int height, int width)
{
	u32 *dest;
	int rows, i;
	u32 cval[4];

	dest = (u32 *)(info->screen_base + sy * next_line + (sx & ~15) / (8 / BPL));
	if (sx & 15) {
		u8 *dest8 = (u8 *)dest + 1;

		expand8_col2mask(color, cval);

		for (i = height; i; i--) {
			fill8_col(dest8, cval);
			dest8 += next_line;
		}
		dest += BPL / 2;
		width -= 8;
	}

	expand16_col2mask(color, cval);
	rows = width >> 4;
	if (rows) {
		u32 *d = dest;
		u32 off = next_line - rows * BPL * 2;
		for (i = height; i; i--) {
			d = fill16_col(d, rows, cval);
			d = (u32 *)((long)d + off);
		}
		dest += rows * BPL / 2;
		width &= 15;
	}

	if (width) {
		u8 *dest8 = (u8 *)dest;

		expand8_col2mask(color, cval);

		for (i = height; i; i--) {
			fill8_col(dest8, cval);
			dest8 += next_line;
		}
	}
}

void atafb_iplan2p8_linefill(struct fb_info *info, u_long next_line,
			     int dy, int dx, u32 width,
			     const u8 *data, u32 bgcolor, u32 fgcolor)
{
	u32 *dest;
	const u16 *data16;
	int rows;
	u32 fgm[4], bgm[4], m;

	dest = (u32 *)(info->screen_base + dy * next_line + (dx & ~15) / (8 / BPL));
	if (dx & 15) {
		fill8_2col((u8 *)dest + 1, fgcolor, bgcolor, *data++);
		dest += BPL / 2;
		width -= 8;
	}

	if (width >= 16) {
		data16 = (const u16 *)data;
		expand16_2col2mask(fgcolor, bgcolor, fgm, bgm);

		for (rows = width / 16; rows; rows--) {
			u16 d = *data16++;
			m = d | ((u32)d << 16);
			*dest++ = (m & fgm[0]) ^ bgm[0];
			*dest++ = (m & fgm[1]) ^ bgm[1];
			*dest++ = (m & fgm[2]) ^ bgm[2];
			*dest++ = (m & fgm[3]) ^ bgm[3];
		}

		data = (const u8 *)data16;
		width &= 15;
	}

	if (width)
		fill8_2col((u8 *)dest, fgcolor, bgcolor, *data);
}

#ifdef MODULE
MODULE_LICENSE("GPL");

int init_module(void)
{
	return 0;
}

void cleanup_module(void)
{
}
#endif /* MODULE */


    /*
     *  Visible symbols for modules
     */

EXPORT_SYMBOL(atafb_iplan2p8_copyarea);
EXPORT_SYMBOL(atafb_iplan2p8_fillrect);
EXPORT_SYMBOL(atafb_iplan2p8_linefill);
5'>1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220











































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































                                                                                                      
/*
 *  linux/mm/page_alloc.c
 *
 *  Manages the free list, the system allocates free pages here.
 *  Note that kmalloc() lives in slab.c
 *
 *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 *  Swap reorganised 29.12.95, Stephen Tweedie
 *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
 *  Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
 *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
 *  Zone balancing, Kanoj Sarcar, SGI, Jan 2000
 *  Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
 *          (lots of bits borrowed from Ingo Molnar & Andrew Morton)
 */

#include <linux/config.h>
#include <linux/stddef.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/interrupt.h>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/suspend.h>
#include <linux/pagevec.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/notifier.h>
#include <linux/topology.h>
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
#include <linux/nodemask.h>
#include <linux/vmalloc.h>

#include <asm/tlbflush.h>
#include "internal.h"

/*
 * MCD - HACK: Find somewhere to initialize this EARLY, or make this
 * initializer cleaner
 */
nodemask_t node_online_map = { { [0] = 1UL } };
nodemask_t node_possible_map = NODE_MASK_ALL;
struct pglist_data *pgdat_list;
unsigned long totalram_pages;
unsigned long totalhigh_pages;
long nr_swap_pages;

/*
 * results with 256, 32 in the lowmem_reserve sysctl:
 *	1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
 *	1G machine -> (16M dma, 784M normal, 224M high)
 *	NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
 *	HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
 *	HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
 */
int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = { 256, 32 };

EXPORT_SYMBOL(totalram_pages);
EXPORT_SYMBOL(nr_swap_pages);

/*
 * Used by page_zone() to look up the address of the struct zone whose
 * id is encoded in the upper bits of page->flags
 */
struct zone *zone_table[1 << (ZONES_SHIFT + NODES_SHIFT)];
EXPORT_SYMBOL(zone_table);

static char *zone_names[MAX_NR_ZONES] = { "DMA", "Normal", "HighMem" };
int min_free_kbytes = 1024;

unsigned long __initdata nr_kernel_pages;
unsigned long __initdata nr_all_pages;

/*
 * Temporary debugging check for pages not lying within a given zone.
 */
static int bad_range(struct zone *zone, struct page *page)
{
	if (page_to_pfn(page) >= zone->zone_start_pfn + zone->spanned_pages)
		return 1;
	if (page_to_pfn(page) < zone->zone_start_pfn)
		return 1;
#ifdef CONFIG_HOLES_IN_ZONE
	if (!pfn_valid(page_to_pfn(page)))
		return 1;
#endif
	if (zone != page_zone(page))
		return 1;
	return 0;
}

static void bad_page(const char *function, struct page *page)
{
	printk(KERN_EMERG "Bad page state at %s (in process '%s', page %p)\n",
		function, current->comm, page);
	printk(KERN_EMERG "flags:0x%0*lx mapping:%p mapcount:%d count:%d\n",
		(int)(2*sizeof(page_flags_t)), (unsigned long)page->flags,
		page->mapping, page_mapcount(page), page_count(page));
	printk(KERN_EMERG "Backtrace:\n");
	dump_stack();
	printk(KERN_EMERG "Trying to fix it up, but a reboot is needed\n");
	page->flags &= ~(1 << PG_private	|
			1 << PG_locked	|
			1 << PG_lru	|
			1 << PG_active	|
			1 << PG_dirty	|
			1 << PG_swapcache |
			1 << PG_writeback);
	set_page_count(page, 0);
	reset_page_mapcount(page);
	page->mapping = NULL;
	tainted |= TAINT_BAD_PAGE;
}

#ifndef CONFIG_HUGETLB_PAGE
#define prep_compound_page(page, order) do { } while (0)
#define destroy_compound_page(page, order) do { } while (0)
#else
/*
 * Higher-order pages are called "compound pages".  They are structured thusly:
 *
 * The first PAGE_SIZE page is called the "head page".
 *
 * The remaining PAGE_SIZE pages are called "tail pages".
 *
 * All pages have PG_compound set.  All pages have their ->private pointing at
 * the head page (even the head page has this).
 *
 * The first tail page's ->mapping, if non-zero, holds the address of the
 * compound page's put_page() function.
 *
 * The order of the allocation is stored in the first tail page's ->index
 * This is only for debug at present.  This usage means that zero-order pages
 * may not be compound.
 */
static void prep_compound_page(struct page *page, unsigned long order)
{
	int i;
	int nr_pages = 1 << order;

	page[1].mapping = NULL;
	page[1].index = order;
	for (i = 0; i < nr_pages; i++) {
		struct page *p = page + i;

		SetPageCompound(p);
		p->private = (unsigned long)page;
	}
}

static void destroy_compound_page(struct page *page, unsigned long order)
{
	int i;
	int nr_pages = 1 << order;

	if (!PageCompound(page))
		return;

	if (page[1].index != order)
		bad_page(__FUNCTION__, page);

	for (i = 0; i < nr_pages; i++) {
		struct page *p = page + i;

		if (!PageCompound(p))
			bad_page(__FUNCTION__, page);
		if (p->private != (unsigned long)page)
			bad_page(__FUNCTION__, page);
		ClearPageCompound(p);
	}
}
#endif		/* CONFIG_HUGETLB_PAGE */

/*
 * function for dealing with page's order in buddy system.
 * zone->lock is already acquired when we use these.
 * So, we don't need atomic page->flags operations here.
 */
static inline unsigned long page_order(struct page *page) {
	return page->private;
}

static inline void set_page_order(struct page *page, int order) {
	page->private = order;
	__SetPagePrivate(page);
}

static inline void rmv_page_order(struct page *page)
{
	__ClearPagePrivate(page);
	page->private = 0;
}

/*
 * Locate the struct page for both the matching buddy in our
 * pair (buddy1) and the combined O(n+1) page they form (page).
 *
 * 1) Any buddy B1 will have an order O twin B2 which satisfies
 * the following equation:
 *     B2 = B1 ^ (1 << O)
 * For example, if the starting buddy (buddy2) is #8 its order
 * 1 buddy is #10:
 *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
 *
 * 2) Any buddy B will have an order O+1 parent P which
 * satisfies the following equation:
 *     P = B & ~(1 << O)
 *
 * Assumption: *_mem_map is contigious at least up to MAX_ORDER
 */
static inline struct page *
__page_find_buddy(struct page *page, unsigned long page_idx, unsigned int order)
{
	unsigned long buddy_idx = page_idx ^ (1 << order);

	return page + (buddy_idx - page_idx);
}

static inline unsigned long
__find_combined_index(unsigned long page_idx, unsigned int order)
{
	return (page_idx & ~(1 << order));
}

/*
 * This function checks whether a page is free && is the buddy
 * we can do coalesce a page and its buddy if
 * (a) the buddy is free &&
 * (b) the buddy is on the buddy system &&
 * (c) a page and its buddy have the same order.
 * for recording page's order, we use page->private and PG_private.
 *
 */
static inline int page_is_buddy(struct page *page, int order)
{
       if (PagePrivate(page)           &&
           (page_order(page) == order) &&
           !PageReserved(page)         &&
            page_count(page) == 0)
               return 1;
       return 0;
}

/*
 * Freeing function for a buddy system allocator.
 *
 * The concept of a buddy system is to maintain direct-mapped table
 * (containing bit values) for memory blocks of various "orders".
 * The bottom level table contains the map for the smallest allocatable
 * units of memory (here, pages), and each level above it describes
 * pairs of units from the levels below, hence, "buddies".
 * At a high level, all that happens here is marking the table entry
 * at the bottom level available, and propagating the changes upward
 * as necessary, plus some accounting needed to play nicely with other
 * parts of the VM system.
 * At each level, we keep a list of pages, which are heads of continuous
 * free pages of length of (1 << order) and marked with PG_Private.Page's
 * order is recorded in page->private field.
 * So when we are allocating or freeing one, we can derive the state of the
 * other.  That is, if we allocate a small block, and both were   
 * free, the remainder of the region must be split into blocks.   
 * If a block is freed, and its buddy is also free, then this
 * triggers coalescing into a block of larger size.            
 *
 * -- wli
 */

static inline void __free_pages_bulk (struct page *page,
		struct zone *zone, unsigned int order)
{
	unsigned long page_idx;
	int order_size = 1 << order;

	if (unlikely(order))
		destroy_compound_page(page, order);

	page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);

	BUG_ON(page_idx & (order_size - 1));
	BUG_ON(bad_range(zone, page));

	zone->free_pages += order_size;
	while (order < MAX_ORDER-1) {
		unsigned long combined_idx;
		struct free_area *area;
		struct page *buddy;

		combined_idx = __find_combined_index(page_idx, order);
		buddy = __page_find_buddy(page, page_idx, order);

		if (bad_range(zone, buddy))
			break;
		if (!page_is_buddy(buddy, order))
			break;		/* Move the buddy up one level. */
		list_del(&buddy->lru);
		area = zone->free_area + order;
		area->nr_free--;
		rmv_page_order(buddy);
		page = page + (combined_idx - page_idx);
		page_idx = combined_idx;
		order++;
	}
	set_page_order(page, order);
	list_add(&page->lru, &zone->free_area[order].free_list);
	zone->free_area[order].nr_free++;
}

static inline void free_pages_check(const char *function, struct page *page)
{
	if (	page_mapcount(page) ||
		page->mapping != NULL ||
		page_count(page) != 0 ||
		(page->flags & (
			1 << PG_lru	|
			1 << PG_private |
			1 << PG_locked	|
			1 << PG_active	|
			1 << PG_reclaim	|
			1 << PG_slab	|
			1 << PG_swapcache |
			1 << PG_writeback )))
		bad_page(function, page);
	if (PageDirty(page))
		ClearPageDirty(page);
}

/*
 * Frees a list of pages. 
 * Assumes all pages on list are in same zone, and of same order.
 * count is the number of pages to free, or 0 for all on the list.
 *
 * If the zone was previously in an "all pages pinned" state then look to
 * see if this freeing clears that state.
 *
 * And clear the zone's pages_scanned counter, to hold off the "all pages are
 * pinned" detection logic.
 */
static int
free_pages_bulk(struct zone *zone, int count,
		struct list_head *list, unsigned int order)
{
	unsigned long flags;
	struct page *page = NULL;
	int ret = 0;

	spin_lock_irqsave(&zone->lock, flags);
	zone->all_unreclaimable = 0;
	zone->pages_scanned = 0;
	while (!list_empty(list) && count--) {
		page = list_entry(list->prev, struct page, lru);
		/* have to delete it as __free_pages_bulk list manipulates */
		list_del(&page->lru);
		__free_pages_bulk(page, zone, order);
		ret++;
	}
	spin_unlock_irqrestore(&zone->lock, flags);
	return ret;
}

void __free_pages_ok(struct page *page, unsigned int order)
{
	LIST_HEAD(list);
	int i;

	arch_free_page(page, order);

	mod_page_state(pgfree, 1 << order);

#ifndef CONFIG_MMU
	if (order > 0)
		for (i = 1 ; i < (1 << order) ; ++i)
			__put_page(page + i);
#endif

	for (i = 0 ; i < (1 << order) ; ++i)
		free_pages_check(__FUNCTION__, page + i);
	list_add(&page->lru, &list);
	kernel_map_pages(page, 1<<order, 0);
	free_pages_bulk(page_zone(page), 1, &list, order);
}


/*
 * The order of subdivision here is critical for the IO subsystem.
 * Please do not alter this order without good reasons and regression
 * testing. Specifically, as large blocks of memory are subdivided,
 * the order in which smaller blocks are delivered depends on the order
 * they're subdivided in this function. This is the primary factor
 * influencing the order in which pages are delivered to the IO
 * subsystem according to empirical testing, and this is also justified
 * by considering the behavior of a buddy system containing a single
 * large block of memory acted on by a series of small allocations.
 * This behavior is a critical factor in sglist merging's success.
 *
 * -- wli
 */
static inline struct page *
expand(struct zone *zone, struct page *page,
 	int low, int high, struct free_area *area)
{
	unsigned long size = 1 << high;

	while (high > low) {
		area--;
		high--;
		size >>= 1;
		BUG_ON(bad_range(zone, &page[size]));
		list_add(&page[size].lru, &area->free_list);
		area->nr_free++;
		set_page_order(&page[size], high);
	}
	return page;
}

void set_page_refs(struct page *page, int order)
{
#ifdef CONFIG_MMU
	set_page_count(page, 1);
#else
	int i;

	/*
	 * We need to reference all the pages for this order, otherwise if
	 * anyone accesses one of the pages with (get/put) it will be freed.
	 * - eg: access_process_vm()
	 */
	for (i = 0; i < (1 << order); i++)
		set_page_count(page + i, 1);
#endif /* CONFIG_MMU */
}

/*
 * This page is about to be returned from the page allocator
 */
static void prep_new_page(struct page *page, int order)
{
	if (page->mapping || page_mapcount(page) ||
	    (page->flags & (
			1 << PG_private	|
			1 << PG_locked	|
			1 << PG_lru	|
			1 << PG_active	|
			1 << PG_dirty	|
			1 << PG_reclaim	|
			1 << PG_swapcache |
			1 << PG_writeback )))
		bad_page(__FUNCTION__, page);

	page->flags &= ~(1 << PG_uptodate | 1 << PG_error |
			1 << PG_referenced | 1 << PG_arch_1 |
			1 << PG_checked | 1 << PG_mappedtodisk);
	page->private = 0;
	set_page_refs(page, order);
	kernel_map_pages(page, 1 << order, 1);
}

/* 
 * Do the hard work of removing an element from the buddy allocator.
 * Call me with the zone->lock already held.
 */
static struct page *__rmqueue(struct zone *zone, unsigned int order)
{
	struct free_area * area;
	unsigned int current_order;
	struct page *page;

	for (current_order = order; current_order < MAX_ORDER; ++current_order) {
		area = zone->free_area + current_order;
		if (list_empty(&area->free_list))
			continue;

		page = list_entry(area->free_list.next, struct page, lru);
		list_del(&page->lru);
		rmv_page_order(page);
		area->nr_free--;
		zone->free_pages -= 1UL << order;
		return expand(zone, page, order, current_order, area);
	}

	return NULL;
}

/* 
 * Obtain a specified number of elements from the buddy allocator, all under
 * a single hold of the lock, for efficiency.  Add them to the supplied list.
 * Returns the number of new pages which were placed at *list.
 */
static int rmqueue_bulk(struct zone *zone, unsigned int order, 
			unsigned long count, struct list_head *list)
{
	unsigned long flags;
	int i;
	int allocated = 0;
	struct page *page;
	
	spin_lock_irqsave(&zone->lock, flags);
	for (i = 0; i < count; ++i) {
		page = __rmqueue(zone, order);
		if (page == NULL)
			break;
		allocated++;
		list_add_tail(&page->lru, list);
	}
	spin_unlock_irqrestore(&zone->lock, flags);
	return allocated;
}

#if defined(CONFIG_PM) || defined(CONFIG_HOTPLUG_CPU)
static void __drain_pages(unsigned int cpu)
{
	struct zone *zone;
	int i;

	for_each_zone(zone) {
		struct per_cpu_pageset *pset;

		pset = &zone->pageset[cpu];
		for (i = 0; i < ARRAY_SIZE(pset->pcp); i++) {
			struct per_cpu_pages *pcp;

			pcp = &pset->pcp[i];
			pcp->count -= free_pages_bulk(zone, pcp->count,
						&pcp->list, 0);
		}
	}
}
#endif /* CONFIG_PM || CONFIG_HOTPLUG_CPU */

#ifdef CONFIG_PM

void mark_free_pages(struct zone *zone)
{
	unsigned long zone_pfn, flags;
	int order;
	struct list_head *curr;

	if (!zone->spanned_pages)
		return;

	spin_lock_irqsave(&zone->lock, flags);
	for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
		ClearPageNosaveFree(pfn_to_page(zone_pfn + zone->zone_start_pfn));

	for (order = MAX_ORDER - 1; order >= 0; --order)
		list_for_each(curr, &zone->free_area[order].free_list) {
			unsigned long start_pfn, i;

			start_pfn = page_to_pfn(list_entry(curr, struct page, lru));

			for (i=0; i < (1<<order); i++)
				SetPageNosaveFree(pfn_to_page(start_pfn+i));
	}
	spin_unlock_irqrestore(&zone->lock, flags);
}

/*
 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
 */
void drain_local_pages(void)
{
	unsigned long flags;

	local_irq_save(flags);	
	__drain_pages(smp_processor_id());
	local_irq_restore(flags);	
}
#endif /* CONFIG_PM */

static void zone_statistics(struct zonelist *zonelist, struct zone *z)
{
#ifdef CONFIG_NUMA
	unsigned long flags;
	int cpu;
	pg_data_t *pg = z->zone_pgdat;
	pg_data_t *orig = zonelist->zones[0]->zone_pgdat;
	struct per_cpu_pageset *p;

	local_irq_save(flags);
	cpu = smp_processor_id();
	p = &z->pageset[cpu];
	if (pg == orig) {
		z->pageset[cpu].numa_hit++;
	} else {
		p->numa_miss++;
		zonelist->zones[0]->pageset[cpu].numa_foreign++;
	}
	if (pg == NODE_DATA(numa_node_id()))
		p->local_node++;
	else
		p->other_node++;
	local_irq_restore(flags);
#endif
}

/*
 * Free a 0-order page
 */
static void FASTCALL(free_hot_cold_page(struct page *page, int cold));
static void fastcall free_hot_cold_page(struct page *page, int cold)
{
	struct zone *zone = page_zone(page);
	struct per_cpu_pages *pcp;
	unsigned long flags;

	arch_free_page(page, 0);

	kernel_map_pages(page, 1, 0);
	inc_page_state(pgfree);
	if (PageAnon(page))
		page->mapping = NULL;
	free_pages_check(__FUNCTION__, page);
	pcp = &zone->pageset[get_cpu()].pcp[cold];
	local_irq_save(flags);
	if (pcp->count >= pcp->high)
		pcp->count -= free_pages_bulk(zone, pcp->batch, &pcp->list, 0);
	list_add(&page->lru, &pcp->list);
	pcp->count++;
	local_irq_restore(flags);
	put_cpu();
}

void fastcall free_hot_page(struct page *page)
{
	free_hot_cold_page(page, 0);
}
	
void fastcall free_cold_page(struct page *page)
{
	free_hot_cold_page(page, 1);
}

static inline void prep_zero_page(struct page *page, int order, unsigned int __nocast gfp_flags)
{
	int i;

	BUG_ON((gfp_flags & (__GFP_WAIT | __GFP_HIGHMEM)) == __GFP_HIGHMEM);
	for(i = 0; i < (1 << order); i++)
		clear_highpage(page + i);
}

/*
 * Really, prep_compound_page() should be called from __rmqueue_bulk().  But
 * we cheat by calling it from here, in the order > 0 path.  Saves a branch
 * or two.
 */
static struct page *
buffered_rmqueue(struct zone *zone, int order, unsigned int __nocast gfp_flags)
{
	unsigned long flags;
	struct page *page = NULL;
	int cold = !!(gfp_flags & __GFP_COLD);

	if (order == 0) {
		struct per_cpu_pages *pcp;

		pcp = &zone->pageset[get_cpu()].pcp[cold];
		local_irq_save(flags);
		if (pcp->count <= pcp->low)
			pcp->count += rmqueue_bulk(zone, 0,
						pcp->batch, &pcp->list);
		if (pcp->count) {
			page = list_entry(pcp->list.next, struct page, lru);
			list_del(&page->lru);
			pcp->count--;
		}
		local_irq_restore(flags);
		put_cpu();
	}

	if (page == NULL) {
		spin_lock_irqsave(&zone->lock, flags);
		page = __rmqueue(zone, order);
		spin_unlock_irqrestore(&zone->lock, flags);
	}

	if (page != NULL) {
		BUG_ON(bad_range(zone, page));
		mod_page_state_zone(zone, pgalloc, 1 << order);
		prep_new_page(page, order);

		if (gfp_flags & __GFP_ZERO)
			prep_zero_page(page, order, gfp_flags);

		if (order && (gfp_flags & __GFP_COMP))
			prep_compound_page(page, order);
	}
	return page;
}

/*
 * Return 1 if free pages are above 'mark'. This takes into account the order
 * of the allocation.
 */
int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
		      int classzone_idx, int can_try_harder, int gfp_high)
{
	/* free_pages my go negative - that's OK */
	long min = mark, free_pages = z->free_pages - (1 << order) + 1;
	int o;

	if (gfp_high)
		min -= min / 2;
	if (can_try_harder)
		min -= min / 4;

	if (free_pages <= min + z->lowmem_reserve[classzone_idx])
		return 0;
	for (o = 0; o < order; o++) {
		/* At the next order, this order's pages become unavailable */
		free_pages -= z->free_area[o].nr_free << o;

		/* Require fewer higher order pages to be free */
		min >>= 1;

		if (free_pages <= min)
			return 0;
	}
	return 1;
}

/*
 * This is the 'heart' of the zoned buddy allocator.
 */
struct page * fastcall
__alloc_pages(unsigned int __nocast gfp_mask, unsigned int order,
		struct zonelist *zonelist)
{
	const int wait = gfp_mask & __GFP_WAIT;
	struct zone **zones, *z;
	struct page *page;
	struct reclaim_state reclaim_state;
	struct task_struct *p = current;
	int i;
	int classzone_idx;
	int do_retry;
	int can_try_harder;
	int did_some_progress;

	might_sleep_if(wait);

	/*
	 * The caller may dip into page reserves a bit more if the caller
	 * cannot run direct reclaim, or is the caller has realtime scheduling
	 * policy
	 */
	can_try_harder = (unlikely(rt_task(p)) && !in_interrupt()) || !wait;

	zones = zonelist->zones;  /* the list of zones suitable for gfp_mask */

	if (unlikely(zones[0] == NULL)) {
		/* Should this ever happen?? */
		return NULL;
	}

	classzone_idx = zone_idx(zones[0]);

 restart:
	/* Go through the zonelist once, looking for a zone with enough free */
	for (i = 0; (z = zones[i]) != NULL; i++) {

		if (!zone_watermark_ok(z, order, z->pages_low,
				       classzone_idx, 0, 0))
			continue;

		if (!cpuset_zone_allowed(z))
			continue;

		page = buffered_rmqueue(z, order, gfp_mask);
		if (page)
			goto got_pg;
	}

	for (i = 0; (z = zones[i]) != NULL; i++)
		wakeup_kswapd(z, order);

	/*
	 * Go through the zonelist again. Let __GFP_HIGH and allocations
	 * coming from realtime tasks to go deeper into reserves
	 *
	 * This is the last chance, in general, before the goto nopage.
	 * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
	 */
	for (i = 0; (z = zones[i]) != NULL; i++) {
		if (!zone_watermark_ok(z, order, z->pages_min,
				       classzone_idx, can_try_harder,
				       gfp_mask & __GFP_HIGH))
			continue;

		if (wait && !cpuset_zone_allowed(z))
			continue;

		page = buffered_rmqueue(z, order, gfp_mask);
		if (page)
			goto got_pg;
	}

	/* This allocation should allow future memory freeing. */
	if (((p->flags & PF_MEMALLOC) || unlikely(test_thread_flag(TIF_MEMDIE))) && !in_interrupt()) {
		/* go through the zonelist yet again, ignoring mins */
		for (i = 0; (z = zones[i]) != NULL; i++) {
			if (!cpuset_zone_allowed(z))
				continue;
			page = buffered_rmqueue(z, order, gfp_mask);
			if (page)
				goto got_pg;
		}
		goto nopage;
	}

	/* Atomic allocations - we can't balance anything */
	if (!wait)
		goto nopage;

rebalance:
	cond_resched();

	/* We now go into synchronous reclaim */
	p->flags |= PF_MEMALLOC;
	reclaim_state.reclaimed_slab = 0;
	p->reclaim_state = &reclaim_state;

	did_some_progress = try_to_free_pages(zones, gfp_mask, order);

	p->reclaim_state = NULL;
	p->flags &= ~PF_MEMALLOC;

	cond_resched();

	if (likely(did_some_progress)) {
		/*
		 * Go through the zonelist yet one more time, keep
		 * very high watermark here, this is only to catch
		 * a parallel oom killing, we must fail if we're still
		 * under heavy pressure.
		 */
		for (i = 0; (z = zones[i]) != NULL; i++) {
			if (!zone_watermark_ok(z, order, z->pages_min,
					       classzone_idx, can_try_harder,
					       gfp_mask & __GFP_HIGH))
				continue;

			if (!cpuset_zone_allowed(z))
				continue;

			page = buffered_rmqueue(z, order, gfp_mask);
			if (page)
				goto got_pg;
		}
	} else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
		/*
		 * Go through the zonelist yet one more time, keep
		 * very high watermark here, this is only to catch
		 * a parallel oom killing, we must fail if we're still
		 * under heavy pressure.
		 */
		for (i = 0; (z = zones[i]) != NULL; i++) {
			if (!zone_watermark_ok(z, order, z->pages_high,
					       classzone_idx, 0, 0))
				continue;

			if (!cpuset_zone_allowed(z))
				continue;

			page = buffered_rmqueue(z, order, gfp_mask);
			if (page)
				goto got_pg;
		}

		out_of_memory(gfp_mask);
		goto restart;
	}

	/*
	 * Don't let big-order allocations loop unless the caller explicitly
	 * requests that.  Wait for some write requests to complete then retry.
	 *
	 * In this implementation, __GFP_REPEAT means __GFP_NOFAIL for order
	 * <= 3, but that may not be true in other implementations.
	 */
	do_retry = 0;
	if (!(gfp_mask & __GFP_NORETRY)) {
		if ((order <= 3) || (gfp_mask & __GFP_REPEAT))
			do_retry = 1;
		if (gfp_mask & __GFP_NOFAIL)
			do_retry = 1;
	}
	if (do_retry) {
		blk_congestion_wait(WRITE, HZ/50);
		goto rebalance;
	}

nopage:
	if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit()) {
		printk(KERN_WARNING "%s: page allocation failure."
			" order:%d, mode:0x%x\n",
			p->comm, order, gfp_mask);
		dump_stack();
	}
	return NULL;
got_pg:
	zone_statistics(zonelist, z);
	return page;
}

EXPORT_SYMBOL(__alloc_pages);

/*
 * Common helper functions.
 */
fastcall unsigned long __get_free_pages(unsigned int __nocast gfp_mask, unsigned int order)
{
	struct page * page;
	page = alloc_pages(gfp_mask, order);
	if (!page)
		return 0;
	return (unsigned long) page_address(page);
}

EXPORT_SYMBOL(__get_free_pages);

fastcall unsigned long get_zeroed_page(unsigned int __nocast gfp_mask)
{
	struct page * page;

	/*
	 * get_zeroed_page() returns a 32-bit address, which cannot represent
	 * a highmem page
	 */
	BUG_ON(gfp_mask & __GFP_HIGHMEM);

	page = alloc_pages(gfp_mask | __GFP_ZERO, 0);
	if (page)
		return (unsigned long) page_address(page);
	return 0;
}

EXPORT_SYMBOL(get_zeroed_page);

void __pagevec_free(struct pagevec *pvec)
{
	int i = pagevec_count(pvec);

	while (--i >= 0)
		free_hot_cold_page(pvec->pages[i], pvec->cold);
}

fastcall void __free_pages(struct page *page, unsigned int order)
{
	if (!PageReserved(page) && put_page_testzero(page)) {
		if (order == 0)
			free_hot_page(page);
		else
			__free_pages_ok(page, order);
	}
}

EXPORT_SYMBOL(__free_pages);

fastcall void free_pages(unsigned long addr, unsigned int order)
{
	if (addr != 0) {
		BUG_ON(!virt_addr_valid((void *)addr));
		__free_pages(virt_to_page((void *)addr), order);
	}
}

EXPORT_SYMBOL(free_pages);

/*
 * Total amount of free (allocatable) RAM:
 */
unsigned int nr_free_pages(void)
{
	unsigned int sum = 0;
	struct zone *zone;

	for_each_zone(zone)
		sum += zone->free_pages;

	return sum;
}

EXPORT_SYMBOL(nr_free_pages);

#ifdef CONFIG_NUMA
unsigned int nr_free_pages_pgdat(pg_data_t *pgdat)
{
	unsigned int i, sum = 0;

	for (i = 0; i < MAX_NR_ZONES; i++)
		sum += pgdat->node_zones[i].free_pages;

	return sum;
}
#endif

static unsigned int nr_free_zone_pages(int offset)
{
	pg_data_t *pgdat;
	unsigned int sum = 0;

	for_each_pgdat(pgdat) {
		struct zonelist *zonelist = pgdat->node_zonelists + offset;
		struct zone **zonep = zonelist->zones;
		struct zone *zone;

		for (zone = *zonep++; zone; zone = *zonep++) {
			unsigned long size = zone->present_pages;
			unsigned long high = zone->pages_high;
			if (size > high)
				sum += size - high;
		}
	}

	return sum;
}

/*
 * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
 */
unsigned int nr_free_buffer_pages(void)
{
	return nr_free_zone_pages(GFP_USER & GFP_ZONEMASK);
}

/*
 * Amount of free RAM allocatable within all zones
 */
unsigned int nr_free_pagecache_pages(void)
{
	return nr_free_zone_pages(GFP_HIGHUSER & GFP_ZONEMASK);
}

#ifdef CONFIG_HIGHMEM
unsigned int nr_free_highpages (void)
{
	pg_data_t *pgdat;
	unsigned int pages = 0;

	for_each_pgdat(pgdat)
		pages += pgdat->node_zones[ZONE_HIGHMEM].free_pages;

	return pages;
}
#endif

#ifdef CONFIG_NUMA
static void show_node(struct zone *zone)
{
	printk("Node %d ", zone->zone_pgdat->node_id);
}
#else
#define show_node(zone)	do { } while (0)
#endif

/*
 * Accumulate the page_state information across all CPUs.
 * The result is unavoidably approximate - it can change
 * during and after execution of this function.
 */
static DEFINE_PER_CPU(struct page_state, page_states) = {0};

atomic_t nr_pagecache = ATOMIC_INIT(0);
EXPORT_SYMBOL(nr_pagecache);
#ifdef CONFIG_SMP
DEFINE_PER_CPU(long, nr_pagecache_local) = 0;
#endif

void __get_page_state(struct page_state *ret, int nr)
{
	int cpu = 0;

	memset(ret, 0, sizeof(*ret));

	cpu = first_cpu(cpu_online_map);
	while (cpu < NR_CPUS) {
		unsigned long *in, *out, off;

		in = (unsigned long *)&per_cpu(page_states, cpu);

		cpu = next_cpu(cpu, cpu_online_map);

		if (cpu < NR_CPUS)
			prefetch(&per_cpu(page_states, cpu));

		out = (unsigned long *)ret;
		for (off = 0; off < nr; off++)
			*out++ += *in++;
	}
}

void get_page_state(struct page_state *ret)
{
	int nr;

	nr = offsetof(struct page_state, GET_PAGE_STATE_LAST);
	nr /= sizeof(unsigned long);

	__get_page_state(ret, nr + 1);
}

void get_full_page_state(struct page_state *ret)
{
	__get_page_state(ret, sizeof(*ret) / sizeof(unsigned long));
}

unsigned long __read_page_state(unsigned offset)
{
	unsigned long ret = 0;
	int cpu;

	for_each_online_cpu(cpu) {
		unsigned long in;

		in = (unsigned long)&per_cpu(page_states, cpu) + offset;
		ret += *((unsigned long *)in);
	}
	return ret;
}

void __mod_page_state(unsigned offset, unsigned long delta)
{
	unsigned long flags;
	void* ptr;

	local_irq_save(flags);
	ptr = &__get_cpu_var(page_states);
	*(unsigned long*)(ptr + offset) += delta;
	local_irq_restore(flags);
}

EXPORT_SYMBOL(__mod_page_state);

void __get_zone_counts(unsigned long *active, unsigned long *inactive,
			unsigned long *free, struct pglist_data *pgdat)
{
	struct zone *zones = pgdat->node_zones;
	int i;

	*active = 0;
	*inactive = 0;
	*free = 0;
	for (i = 0; i < MAX_NR_ZONES; i++) {
		*active += zones[i].nr_active;
		*inactive += zones[i].nr_inactive;
		*free += zones[i].free_pages;
	}
}

void get_zone_counts(unsigned long *active,
		unsigned long *inactive, unsigned long *free)
{
	struct pglist_data *pgdat;

	*active = 0;
	*inactive = 0;
	*free = 0;
	for_each_pgdat(pgdat) {
		unsigned long l, m, n;
		__get_zone_counts(&l, &m, &n, pgdat);
		*active += l;
		*inactive += m;
		*free += n;
	}
}

void si_meminfo(struct sysinfo *val)
{
	val->totalram = totalram_pages;
	val->sharedram = 0;
	val->freeram = nr_free_pages();
	val->bufferram = nr_blockdev_pages();
#ifdef CONFIG_HIGHMEM
	val->totalhigh = totalhigh_pages;
	val->freehigh = nr_free_highpages();
#else
	val->totalhigh = 0;
	val->freehigh = 0;
#endif
	val->mem_unit = PAGE_SIZE;
}

EXPORT_SYMBOL(si_meminfo);

#ifdef CONFIG_NUMA
void si_meminfo_node(struct sysinfo *val, int nid)
{
	pg_data_t *pgdat = NODE_DATA(nid);

	val->totalram = pgdat->node_present_pages;
	val->freeram = nr_free_pages_pgdat(pgdat);
	val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].present_pages;
	val->freehigh = pgdat->node_zones[ZONE_HIGHMEM].free_pages;
	val->mem_unit = PAGE_SIZE;
}
#endif

#define K(x) ((x) << (PAGE_SHIFT-10))

/*
 * Show free area list (used inside shift_scroll-lock stuff)
 * We also calculate the percentage fragmentation. We do this by counting the
 * memory on each free list with the exception of the first item on the list.
 */
void show_free_areas(void)
{
	struct page_state ps;
	int cpu, temperature;
	unsigned long active;
	unsigned long inactive;
	unsigned long free;
	struct zone *zone;

	for_each_zone(zone) {
		show_node(zone);
		printk("%s per-cpu:", zone->name);

		if (!zone->present_pages) {
			printk(" empty\n");
			continue;
		} else
			printk("\n");

		for (cpu = 0; cpu < NR_CPUS; ++cpu) {
			struct per_cpu_pageset *pageset;

			if (!cpu_possible(cpu))
				continue;

			pageset = zone->pageset + cpu;

			for (temperature = 0; temperature < 2; temperature++)
				printk("cpu %d %s: low %d, high %d, batch %d\n",
					cpu,
					temperature ? "cold" : "hot",
					pageset->pcp[temperature].low,
					pageset->pcp[temperature].high,
					pageset->pcp[temperature].batch);
		}
	}

	get_page_state(&ps);
	get_zone_counts(&active, &inactive, &free);

	printk("\nFree pages: %11ukB (%ukB HighMem)\n",
		K(nr_free_pages()),
		K(nr_free_highpages()));

	printk("Active:%lu inactive:%lu dirty:%lu writeback:%lu "
		"unstable:%lu free:%u slab:%lu mapped:%lu pagetables:%lu\n",
		active,
		inactive,
		ps.nr_dirty,
		ps.nr_writeback,
		ps.nr_unstable,
		nr_free_pages(),
		ps.nr_slab,
		ps.nr_mapped,
		ps.nr_page_table_pages);

	for_each_zone(zone) {
		int i;

		show_node(zone);
		printk("%s"
			" free:%lukB"
			" min:%lukB"
			" low:%lukB"
			" high:%lukB"
			" active:%lukB"
			" inactive:%lukB"
			" present:%lukB"
			" pages_scanned:%lu"
			" all_unreclaimable? %s"
			"\n",
			zone->name,
			K(zone->free_pages),
			K(zone->pages_min),
			K(zone->pages_low),
			K(zone->pages_high),
			K(zone->nr_active),
			K(zone->nr_inactive),
			K(zone->present_pages),
			zone->pages_scanned,
			(zone->all_unreclaimable ? "yes" : "no")
			);
		printk("lowmem_reserve[]:");
		for (i = 0; i < MAX_NR_ZONES; i++)
			printk(" %lu", zone->lowmem_reserve[i]);
		printk("\n");
	}

	for_each_zone(zone) {
 		unsigned long nr, flags, order, total = 0;

		show_node(zone);
		printk("%s: ", zone->name);
		if (!zone->present_pages) {
			printk("empty\n");
			continue;
		}

		spin_lock_irqsave(&zone->lock, flags);
		for (order = 0; order < MAX_ORDER; order++) {
			nr = zone->free_area[order].nr_free;
			total += nr << order;
			printk("%lu*%lukB ", nr, K(1UL) << order);
		}
		spin_unlock_irqrestore(&zone->lock, flags);
		printk("= %lukB\n", K(total));
	}

	show_swap_cache_info();
}

/*
 * Builds allocation fallback zone lists.
 */
static int __init build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist, int j, int k)
{
	switch (k) {
		struct zone *zone;
	default:
		BUG();
	case ZONE_HIGHMEM:
		zone = pgdat->node_zones + ZONE_HIGHMEM;
		if (zone->present_pages) {
#ifndef CONFIG_HIGHMEM
			BUG();
#endif
			zonelist->zones[j++] = zone;
		}
	case ZONE_NORMAL:
		zone = pgdat->node_zones + ZONE_NORMAL;
		if (zone->present_pages)
			zonelist->zones[j++] = zone;
	case ZONE_DMA:
		zone = pgdat->node_zones + ZONE_DMA;
		if (zone->present_pages)
			zonelist->zones[j++] = zone;
	}

	return j;
}

#ifdef CONFIG_NUMA
#define MAX_NODE_LOAD (num_online_nodes())
static int __initdata node_load[MAX_NUMNODES];
/**
 * find_next_best_node - find the next node that should appear in a given
 *    node's fallback list
 * @node: node whose fallback list we're appending
 * @used_node_mask: nodemask_t of already used nodes
 *
 * We use a number of factors to determine which is the next node that should
 * appear on a given node's fallback list.  The node should not have appeared
 * already in @node's fallback list, and it should be the next closest node
 * according to the distance array (which contains arbitrary distance values
 * from each node to each node in the system), and should also prefer nodes
 * with no CPUs, since presumably they'll have very little allocation pressure
 * on them otherwise.
 * It returns -1 if no node is found.
 */
static int __init find_next_best_node(int node, nodemask_t *used_node_mask)
{
	int i, n, val;
	int min_val = INT_MAX;
	int best_node = -1;

	for_each_online_node(i) {
		cpumask_t tmp;

		/* Start from local node */
		n = (node+i) % num_online_nodes();

		/* Don't want a node to appear more than once */
		if (node_isset(n, *used_node_mask))
			continue;

		/* Use the local node if we haven't already */
		if (!node_isset(node, *used_node_mask)) {
			best_node = node;
			break;
		}

		/* Use the distance array to find the distance */
		val = node_distance(node, n);

		/* Give preference to headless and unused nodes */
		tmp = node_to_cpumask(n);
		if (!cpus_empty(tmp))
			val += PENALTY_FOR_NODE_WITH_CPUS;

		/* Slight preference for less loaded node */
		val *= (MAX_NODE_LOAD*MAX_NUMNODES);
		val += node_load[n];

		if (val < min_val) {
			min_val = val;
			best_node = n;
		}
	}

	if (best_node >= 0)
		node_set(best_node, *used_node_mask);

	return best_node;
}

static void __init build_zonelists(pg_data_t *pgdat)
{
	int i, j, k, node, local_node;
	int prev_node, load;
	struct zonelist *zonelist;
	nodemask_t used_mask;

	/* initialize zonelists */
	for (i = 0; i < GFP_ZONETYPES; i++) {
		zonelist = pgdat->node_zonelists + i;
		zonelist->zones[0] = NULL;
	}

	/* NUMA-aware ordering of nodes */
	local_node = pgdat->node_id;
	load = num_online_nodes();
	prev_node = local_node;
	nodes_clear(used_mask);
	while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
		/*
		 * We don't want to pressure a particular node.
		 * So adding penalty to the first node in same
		 * distance group to make it round-robin.
		 */
		if (node_distance(local_node, node) !=
				node_distance(local_node, prev_node))
			node_load[node] += load;
		prev_node = node;
		load--;
		for (i = 0; i < GFP_ZONETYPES; i++) {
			zonelist = pgdat->node_zonelists + i;
			for (j = 0; zonelist->zones[j] != NULL; j++);

			k = ZONE_NORMAL;
			if (i & __GFP_HIGHMEM)
				k = ZONE_HIGHMEM;
			if (i & __GFP_DMA)
				k = ZONE_DMA;

	 		j = build_zonelists_node(NODE_DATA(node), zonelist, j, k);
			zonelist->zones[j] = NULL;
		}
	}
}

#else	/* CONFIG_NUMA */

static void __init build_zonelists(pg_data_t *pgdat)
{
	int i, j, k, node, local_node;

	local_node = pgdat->node_id;
	for (i = 0; i < GFP_ZONETYPES; i++) {
		struct zonelist *zonelist;

		zonelist = pgdat->node_zonelists + i;

		j = 0;
		k = ZONE_NORMAL;
		if (i & __GFP_HIGHMEM)
			k = ZONE_HIGHMEM;
		if (i & __GFP_DMA)
			k = ZONE_DMA;

 		j = build_zonelists_node(pgdat, zonelist, j, k);
 		/*
 		 * Now we build the zonelist so that it contains the zones
 		 * of all the other nodes.
 		 * We don't want to pressure a particular node, so when
 		 * building the zones for node N, we make sure that the
 		 * zones coming right after the local ones are those from
 		 * node N+1 (modulo N)
 		 */
		for (node = local_node + 1; node < MAX_NUMNODES; node++) {
			if (!node_online(node))
				continue;
			j = build_zonelists_node(NODE_DATA(node), zonelist, j, k);
		}
		for (node = 0; node < local_node; node++) {
			if (!node_online(node))
				continue;
			j = build_zonelists_node(NODE_DATA(node), zonelist, j, k);
		}

		zonelist->zones[j] = NULL;
	}
}