linux/fs/proc/page.c

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#include <linux/bootmem.h>
#include <linux/compiler.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>
#include "internal.h"
#define KPMSIZE sizeof(u64)
#define KPMMASK (KPMSIZE - 1)
/* /proc/kpagecount - an array exposing page counts
*
* Each entry is a u64 representing the corresponding
* physical page count.
*/
static ssize_t kpagecount_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
u64 __user *out = (u64 __user *)buf;
struct page *ppage;
unsigned long src = *ppos;
unsigned long pfn;
ssize_t ret = 0;
u64 pcount;
pfn = src / KPMSIZE;
count = min_t(size_t, count, (max_pfn * KPMSIZE) - src);
if (src & KPMMASK || count & KPMMASK)
return -EINVAL;
while (count > 0) {
ppage = NULL;
if (pfn_valid(pfn))
ppage = pfn_to_page(pfn);
pfn++;
if (!ppage)
pcount = 0;
else
pcount = page_mapcount(ppage);
if (put_user(pcount, out++)) {
ret = -EFAULT;
break;
}
count -= KPMSIZE;
}
*ppos += (char __user *)out - buf;
if (!ret)
ret = (char __user *)out - buf;
return ret;
}
static const struct file_operations proc_kpagecount_operations = {
.llseek = mem_lseek,
.read = kpagecount_read,
};
/* /proc/kpageflags - an array exposing page flags
*
* Each entry is a u64 representing the corresponding
* physical page flags.
*/
/* These macros are used to decouple internal flags from exported ones */
#define KPF_LOCKED 0
#define KPF_ERROR 1
#define KPF_REFERENCED 2
#define KPF_UPTODATE 3
#define KPF_DIRTY 4
#define KPF_LRU 5
#define KPF_ACTIVE 6
#define KPF_SLAB 7
#define KPF_WRITEBACK 8
#define KPF_RECLAIM 9
#define KPF_BUDDY 10
#define kpf_copy_bit(flags, dstpos, srcpos) (((flags >> srcpos) & 1) << dstpos)
static ssize_t kpageflags_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
u64 __user *out = (u64 __user *)buf;
struct page *ppage;
unsigned long src = *ppos;
unsigned long pfn;
ssize_t ret = 0;
u64 kflags, uflags;
pfn = src / KPMSIZE;
count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
if (src & KPMMASK || count & KPMMASK)
return -EINVAL;
while (count > 0) {
ppage = NULL;
if (pfn_valid(pfn))
ppage = pfn_to_page(pfn);
pfn++;
if (!ppage)
kflags = 0;
else
kflags = ppage->flags;
uflags = kpf_copy_bit(kflags, KPF_LOCKED, PG_locked) |
kpf_copy_bit(kflags, KPF_ERROR, PG_error) |
kpf_copy_bit(kflags, KPF_REFERENCED, PG_referenced) |
kpf_copy_bit(kflags, KPF_UPTODATE, PG_uptodate) |
kpf_copy_bit(kflags, KPF_DIRTY, PG_dirty) |
kpf_copy_bit(kflags, KPF_LRU, PG_lru) |
kpf_copy_bit(kflags, KPF_ACTIVE, PG_active) |
kpf_copy_bit(kflags, KPF_SLAB, PG_slab) |
kpf_copy_bit(kflags, KPF_WRITEBACK, PG_writeback) |
kpf_copy_bit(kflags, KPF_RECLAIM, PG_reclaim) |
kpf_copy_bit(kflags, KPF_BUDDY, PG_buddy);
if (put_user(uflags, out++)) {
ret = -EFAULT;
break;
}
count -= KPMSIZE;
}
*ppos += (char __user *)out - buf;
if (!ret)
ret = (char __user *)out - buf;
return ret;
}
static const struct file_operations proc_kpageflags_operations = {
.llseek = mem_lseek,
.read = kpageflags_read,
};
static int __init proc_page_init(void)
{
proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
return 0;
}
module_init(proc_page_init);