1 #include <linux/bootmem.h>
2 #include <linux/compiler.h>
4 #include <linux/init.h>
7 #include <linux/mmzone.h>
8 #include <linux/proc_fs.h>
9 #include <linux/seq_file.h>
10 #include <linux/hugetlb.h>
11 #include <linux/kernel-page-flags.h>
12 #include <asm/uaccess.h>
15 #define KPMSIZE sizeof(u64)
16 #define KPMMASK (KPMSIZE - 1)
18 /* /proc/kpagecount - an array exposing page counts
20 * Each entry is a u64 representing the corresponding
21 * physical page count.
23 static ssize_t kpagecount_read(struct file *file, char __user *buf,
24 size_t count, loff_t *ppos)
26 u64 __user *out = (u64 __user *)buf;
28 unsigned long src = *ppos;
34 count = min_t(size_t, count, (max_pfn * KPMSIZE) - src);
35 if (src & KPMMASK || count & KPMMASK)
40 ppage = pfn_to_page(pfn);
46 pcount = page_mapcount(ppage);
48 if (put_user(pcount, out)) {
58 *ppos += (char __user *)out - buf;
60 ret = (char __user *)out - buf;
64 static const struct file_operations proc_kpagecount_operations = {
66 .read = kpagecount_read,
69 /* /proc/kpageflags - an array exposing page flags
71 * Each entry is a u64 representing the corresponding
72 * physical page flags.
75 static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit)
77 return ((kflags >> kbit) & 1) << ubit;
80 u64 stable_page_flags(struct page *page)
86 * pseudo flag: KPF_NOPAGE
87 * it differentiates a memory hole from a page with no flags
90 return 1 << KPF_NOPAGE;
96 * pseudo flags for the well known (anonymous) memory mapped pages
98 * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the
99 * simple test in page_mapped() is not enough.
101 if (!PageSlab(page) && page_mapped(page))
109 * compound pages: export both head/tail info
110 * they together define a compound page's start/end pos and order
113 u |= 1 << KPF_COMPOUND_HEAD;
115 u |= 1 << KPF_COMPOUND_TAIL;
119 u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
122 * Caveats on high order pages:
123 * PG_buddy will only be set on the head page; SLUB/SLQB do the same
124 * for PG_slab; SLOB won't set PG_slab at all on compound pages.
126 u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
127 u |= kpf_copy_bit(k, KPF_BUDDY, PG_buddy);
129 u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
130 u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
131 u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate);
132 u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback);
134 u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
135 u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced);
136 u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active);
137 u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim);
139 u |= kpf_copy_bit(k, KPF_SWAPCACHE, PG_swapcache);
140 u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked);
142 u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable);
143 u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked);
145 #ifdef CONFIG_MEMORY_FAILURE
146 u |= kpf_copy_bit(k, KPF_HWPOISON, PG_hwpoison);
149 #ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
150 u |= kpf_copy_bit(k, KPF_UNCACHED, PG_uncached);
153 u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved);
154 u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk);
155 u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private);
156 u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2);
157 u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
158 u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1);
163 static ssize_t kpageflags_read(struct file *file, char __user *buf,
164 size_t count, loff_t *ppos)
166 u64 __user *out = (u64 __user *)buf;
168 unsigned long src = *ppos;
173 count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
174 if (src & KPMMASK || count & KPMMASK)
179 ppage = pfn_to_page(pfn);
183 if (put_user(stable_page_flags(ppage), out)) {
193 *ppos += (char __user *)out - buf;
195 ret = (char __user *)out - buf;
199 static const struct file_operations proc_kpageflags_operations = {
201 .read = kpageflags_read,
204 static int __init proc_page_init(void)
206 proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
207 proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
210 module_init(proc_page_init);