linux/fs/proc/task_mmu.c
Matt Mackall 85863e475e maps4: add /proc/pid/pagemap interface
This interface provides a mapping for each page in an address space to its
physical page frame number, allowing precise determination of what pages are
mapped and what pages are shared between processes.

New in this version:

- headers gone again (as recommended by Dave Hansen and Alan Cox)
- 64-bit entries (as per discussion with Andi Kleen)
- swap pte information exported (from Dave Hansen)
- page walker callback for holes (from Dave Hansen)
- direct put_user I/O (as suggested by Rusty Russell)

This patch folds in cleanups and swap PTE support from Dave Hansen
<haveblue@us.ibm.com>.

Signed-off-by: Matt Mackall <mpm@selenic.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 09:44:16 -08:00

754 lines
18 KiB
C

#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/mount.h>
#include <linux/seq_file.h>
#include <linux/highmem.h>
#include <linux/ptrace.h>
#include <linux/pagemap.h>
#include <linux/ptrace.h>
#include <linux/mempolicy.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <asm/elf.h>
#include <asm/uaccess.h>
#include <asm/tlbflush.h>
#include "internal.h"
char *task_mem(struct mm_struct *mm, char *buffer)
{
unsigned long data, text, lib;
unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
/*
* Note: to minimize their overhead, mm maintains hiwater_vm and
* hiwater_rss only when about to *lower* total_vm or rss. Any
* collector of these hiwater stats must therefore get total_vm
* and rss too, which will usually be the higher. Barriers? not
* worth the effort, such snapshots can always be inconsistent.
*/
hiwater_vm = total_vm = mm->total_vm;
if (hiwater_vm < mm->hiwater_vm)
hiwater_vm = mm->hiwater_vm;
hiwater_rss = total_rss = get_mm_rss(mm);
if (hiwater_rss < mm->hiwater_rss)
hiwater_rss = mm->hiwater_rss;
data = mm->total_vm - mm->shared_vm - mm->stack_vm;
text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK)) >> 10;
lib = (mm->exec_vm << (PAGE_SHIFT-10)) - text;
buffer += sprintf(buffer,
"VmPeak:\t%8lu kB\n"
"VmSize:\t%8lu kB\n"
"VmLck:\t%8lu kB\n"
"VmHWM:\t%8lu kB\n"
"VmRSS:\t%8lu kB\n"
"VmData:\t%8lu kB\n"
"VmStk:\t%8lu kB\n"
"VmExe:\t%8lu kB\n"
"VmLib:\t%8lu kB\n"
"VmPTE:\t%8lu kB\n",
hiwater_vm << (PAGE_SHIFT-10),
(total_vm - mm->reserved_vm) << (PAGE_SHIFT-10),
mm->locked_vm << (PAGE_SHIFT-10),
hiwater_rss << (PAGE_SHIFT-10),
total_rss << (PAGE_SHIFT-10),
data << (PAGE_SHIFT-10),
mm->stack_vm << (PAGE_SHIFT-10), text, lib,
(PTRS_PER_PTE*sizeof(pte_t)*mm->nr_ptes) >> 10);
return buffer;
}
unsigned long task_vsize(struct mm_struct *mm)
{
return PAGE_SIZE * mm->total_vm;
}
int task_statm(struct mm_struct *mm, int *shared, int *text,
int *data, int *resident)
{
*shared = get_mm_counter(mm, file_rss);
*text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
>> PAGE_SHIFT;
*data = mm->total_vm - mm->shared_vm;
*resident = *shared + get_mm_counter(mm, anon_rss);
return mm->total_vm;
}
int proc_exe_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
{
struct vm_area_struct * vma;
int result = -ENOENT;
struct task_struct *task = get_proc_task(inode);
struct mm_struct * mm = NULL;
if (task) {
mm = get_task_mm(task);
put_task_struct(task);
}
if (!mm)
goto out;
down_read(&mm->mmap_sem);
vma = mm->mmap;
while (vma) {
if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file)
break;
vma = vma->vm_next;
}
if (vma) {
*mnt = mntget(vma->vm_file->f_path.mnt);
*dentry = dget(vma->vm_file->f_path.dentry);
result = 0;
}
up_read(&mm->mmap_sem);
mmput(mm);
out:
return result;
}
static void pad_len_spaces(struct seq_file *m, int len)
{
len = 25 + sizeof(void*) * 6 - len;
if (len < 1)
len = 1;
seq_printf(m, "%*c", len, ' ');
}
static void vma_stop(struct proc_maps_private *priv, struct vm_area_struct *vma)
{
if (vma && vma != priv->tail_vma) {
struct mm_struct *mm = vma->vm_mm;
up_read(&mm->mmap_sem);
mmput(mm);
}
}
static void *m_start(struct seq_file *m, loff_t *pos)
{
struct proc_maps_private *priv = m->private;
unsigned long last_addr = m->version;
struct mm_struct *mm;
struct vm_area_struct *vma, *tail_vma = NULL;
loff_t l = *pos;
/* Clear the per syscall fields in priv */
priv->task = NULL;
priv->tail_vma = NULL;
/*
* We remember last_addr rather than next_addr to hit with
* mmap_cache most of the time. We have zero last_addr at
* the beginning and also after lseek. We will have -1 last_addr
* after the end of the vmas.
*/
if (last_addr == -1UL)
return NULL;
priv->task = get_pid_task(priv->pid, PIDTYPE_PID);
if (!priv->task)
return NULL;
mm = mm_for_maps(priv->task);
if (!mm)
return NULL;
tail_vma = get_gate_vma(priv->task);
priv->tail_vma = tail_vma;
/* Start with last addr hint */
vma = find_vma(mm, last_addr);
if (last_addr && vma) {
vma = vma->vm_next;
goto out;
}
/*
* Check the vma index is within the range and do
* sequential scan until m_index.
*/
vma = NULL;
if ((unsigned long)l < mm->map_count) {
vma = mm->mmap;
while (l-- && vma)
vma = vma->vm_next;
goto out;
}
if (l != mm->map_count)
tail_vma = NULL; /* After gate vma */
out:
if (vma)
return vma;
/* End of vmas has been reached */
m->version = (tail_vma != NULL)? 0: -1UL;
up_read(&mm->mmap_sem);
mmput(mm);
return tail_vma;
}
static void *m_next(struct seq_file *m, void *v, loff_t *pos)
{
struct proc_maps_private *priv = m->private;
struct vm_area_struct *vma = v;
struct vm_area_struct *tail_vma = priv->tail_vma;
(*pos)++;
if (vma && (vma != tail_vma) && vma->vm_next)
return vma->vm_next;
vma_stop(priv, vma);
return (vma != tail_vma)? tail_vma: NULL;
}
static void m_stop(struct seq_file *m, void *v)
{
struct proc_maps_private *priv = m->private;
struct vm_area_struct *vma = v;
vma_stop(priv, vma);
if (priv->task)
put_task_struct(priv->task);
}
static int do_maps_open(struct inode *inode, struct file *file,
struct seq_operations *ops)
{
struct proc_maps_private *priv;
int ret = -ENOMEM;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (priv) {
priv->pid = proc_pid(inode);
ret = seq_open(file, ops);
if (!ret) {
struct seq_file *m = file->private_data;
m->private = priv;
} else {
kfree(priv);
}
}
return ret;
}
static int show_map(struct seq_file *m, void *v)
{
struct proc_maps_private *priv = m->private;
struct task_struct *task = priv->task;
struct vm_area_struct *vma = v;
struct mm_struct *mm = vma->vm_mm;
struct file *file = vma->vm_file;
int flags = vma->vm_flags;
unsigned long ino = 0;
dev_t dev = 0;
int len;
if (maps_protect && !ptrace_may_attach(task))
return -EACCES;
if (file) {
struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
dev = inode->i_sb->s_dev;
ino = inode->i_ino;
}
seq_printf(m, "%08lx-%08lx %c%c%c%c %08lx %02x:%02x %lu %n",
vma->vm_start,
vma->vm_end,
flags & VM_READ ? 'r' : '-',
flags & VM_WRITE ? 'w' : '-',
flags & VM_EXEC ? 'x' : '-',
flags & VM_MAYSHARE ? 's' : 'p',
vma->vm_pgoff << PAGE_SHIFT,
MAJOR(dev), MINOR(dev), ino, &len);
/*
* Print the dentry name for named mappings, and a
* special [heap] marker for the heap:
*/
if (file) {
pad_len_spaces(m, len);
seq_path(m, file->f_path.mnt, file->f_path.dentry, "\n");
} else {
const char *name = arch_vma_name(vma);
if (!name) {
if (mm) {
if (vma->vm_start <= mm->start_brk &&
vma->vm_end >= mm->brk) {
name = "[heap]";
} else if (vma->vm_start <= mm->start_stack &&
vma->vm_end >= mm->start_stack) {
name = "[stack]";
}
} else {
name = "[vdso]";
}
}
if (name) {
pad_len_spaces(m, len);
seq_puts(m, name);
}
}
seq_putc(m, '\n');
if (m->count < m->size) /* vma is copied successfully */
m->version = (vma != get_gate_vma(task))? vma->vm_start: 0;
return 0;
}
static struct seq_operations proc_pid_maps_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_map
};
static int maps_open(struct inode *inode, struct file *file)
{
return do_maps_open(inode, file, &proc_pid_maps_op);
}
const struct file_operations proc_maps_operations = {
.open = maps_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
/*
* Proportional Set Size(PSS): my share of RSS.
*
* PSS of a process is the count of pages it has in memory, where each
* page is divided by the number of processes sharing it. So if a
* process has 1000 pages all to itself, and 1000 shared with one other
* process, its PSS will be 1500.
*
* To keep (accumulated) division errors low, we adopt a 64bit
* fixed-point pss counter to minimize division errors. So (pss >>
* PSS_SHIFT) would be the real byte count.
*
* A shift of 12 before division means (assuming 4K page size):
* - 1M 3-user-pages add up to 8KB errors;
* - supports mapcount up to 2^24, or 16M;
* - supports PSS up to 2^52 bytes, or 4PB.
*/
#define PSS_SHIFT 12
struct mem_size_stats
{
struct vm_area_struct *vma;
unsigned long resident;
unsigned long shared_clean;
unsigned long shared_dirty;
unsigned long private_clean;
unsigned long private_dirty;
unsigned long referenced;
u64 pss;
};
static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
void *private)
{
struct mem_size_stats *mss = private;
struct vm_area_struct *vma = mss->vma;
pte_t *pte, ptent;
spinlock_t *ptl;
struct page *page;
int mapcount;
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
for (; addr != end; pte++, addr += PAGE_SIZE) {
ptent = *pte;
if (!pte_present(ptent))
continue;
mss->resident += PAGE_SIZE;
page = vm_normal_page(vma, addr, ptent);
if (!page)
continue;
/* Accumulate the size in pages that have been accessed. */
if (pte_young(ptent) || PageReferenced(page))
mss->referenced += PAGE_SIZE;
mapcount = page_mapcount(page);
if (mapcount >= 2) {
if (pte_dirty(ptent))
mss->shared_dirty += PAGE_SIZE;
else
mss->shared_clean += PAGE_SIZE;
mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount;
} else {
if (pte_dirty(ptent))
mss->private_dirty += PAGE_SIZE;
else
mss->private_clean += PAGE_SIZE;
mss->pss += (PAGE_SIZE << PSS_SHIFT);
}
}
pte_unmap_unlock(pte - 1, ptl);
cond_resched();
return 0;
}
static struct mm_walk smaps_walk = { .pmd_entry = smaps_pte_range };
static int show_smap(struct seq_file *m, void *v)
{
struct vm_area_struct *vma = v;
struct mem_size_stats mss;
int ret;
memset(&mss, 0, sizeof mss);
mss.vma = vma;
if (vma->vm_mm && !is_vm_hugetlb_page(vma))
walk_page_range(vma->vm_mm, vma->vm_start, vma->vm_end,
&smaps_walk, &mss);
ret = show_map(m, v);
if (ret)
return ret;
seq_printf(m,
"Size: %8lu kB\n"
"Rss: %8lu kB\n"
"Pss: %8lu kB\n"
"Shared_Clean: %8lu kB\n"
"Shared_Dirty: %8lu kB\n"
"Private_Clean: %8lu kB\n"
"Private_Dirty: %8lu kB\n"
"Referenced: %8lu kB\n",
(vma->vm_end - vma->vm_start) >> 10,
mss.resident >> 10,
(unsigned long)(mss.pss >> (10 + PSS_SHIFT)),
mss.shared_clean >> 10,
mss.shared_dirty >> 10,
mss.private_clean >> 10,
mss.private_dirty >> 10,
mss.referenced >> 10);
return ret;
}
static struct seq_operations proc_pid_smaps_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_smap
};
static int smaps_open(struct inode *inode, struct file *file)
{
return do_maps_open(inode, file, &proc_pid_smaps_op);
}
const struct file_operations proc_smaps_operations = {
.open = smaps_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
unsigned long end, void *private)
{
struct vm_area_struct *vma = private;
pte_t *pte, ptent;
spinlock_t *ptl;
struct page *page;
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
for (; addr != end; pte++, addr += PAGE_SIZE) {
ptent = *pte;
if (!pte_present(ptent))
continue;
page = vm_normal_page(vma, addr, ptent);
if (!page)
continue;
/* Clear accessed and referenced bits. */
ptep_test_and_clear_young(vma, addr, pte);
ClearPageReferenced(page);
}
pte_unmap_unlock(pte - 1, ptl);
cond_resched();
return 0;
}
static struct mm_walk clear_refs_walk = { .pmd_entry = clear_refs_pte_range };
static ssize_t clear_refs_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct task_struct *task;
char buffer[PROC_NUMBUF], *end;
struct mm_struct *mm;
struct vm_area_struct *vma;
memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count))
return -EFAULT;
if (!simple_strtol(buffer, &end, 0))
return -EINVAL;
if (*end == '\n')
end++;
task = get_proc_task(file->f_path.dentry->d_inode);
if (!task)
return -ESRCH;
mm = get_task_mm(task);
if (mm) {
down_read(&mm->mmap_sem);
for (vma = mm->mmap; vma; vma = vma->vm_next)
if (!is_vm_hugetlb_page(vma))
walk_page_range(mm, vma->vm_start, vma->vm_end,
&clear_refs_walk, vma);
flush_tlb_mm(mm);
up_read(&mm->mmap_sem);
mmput(mm);
}
put_task_struct(task);
if (end - buffer == 0)
return -EIO;
return end - buffer;
}
const struct file_operations proc_clear_refs_operations = {
.write = clear_refs_write,
};
struct pagemapread {
char __user *out, *end;
};
#define PM_ENTRY_BYTES sizeof(u64)
#define PM_RESERVED_BITS 3
#define PM_RESERVED_OFFSET (64 - PM_RESERVED_BITS)
#define PM_RESERVED_MASK (((1LL<<PM_RESERVED_BITS)-1) << PM_RESERVED_OFFSET)
#define PM_SPECIAL(nr) (((nr) << PM_RESERVED_OFFSET) | PM_RESERVED_MASK)
#define PM_NOT_PRESENT PM_SPECIAL(1LL)
#define PM_SWAP PM_SPECIAL(2LL)
#define PM_END_OF_BUFFER 1
static int add_to_pagemap(unsigned long addr, u64 pfn,
struct pagemapread *pm)
{
/*
* Make sure there's room in the buffer for an
* entire entry. Otherwise, only copy part of
* the pfn.
*/
if (pm->out + PM_ENTRY_BYTES >= pm->end) {
if (copy_to_user(pm->out, &pfn, pm->end - pm->out))
return -EFAULT;
pm->out = pm->end;
return PM_END_OF_BUFFER;
}
if (put_user(pfn, pm->out))
return -EFAULT;
pm->out += PM_ENTRY_BYTES;
return 0;
}
static int pagemap_pte_hole(unsigned long start, unsigned long end,
void *private)
{
struct pagemapread *pm = private;
unsigned long addr;
int err = 0;
for (addr = start; addr < end; addr += PAGE_SIZE) {
err = add_to_pagemap(addr, PM_NOT_PRESENT, pm);
if (err)
break;
}
return err;
}
u64 swap_pte_to_pagemap_entry(pte_t pte)
{
swp_entry_t e = pte_to_swp_entry(pte);
return PM_SWAP | swp_type(e) | (swp_offset(e) << MAX_SWAPFILES_SHIFT);
}
static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
void *private)
{
struct pagemapread *pm = private;
pte_t *pte;
int err = 0;
for (; addr != end; addr += PAGE_SIZE) {
u64 pfn = PM_NOT_PRESENT;
pte = pte_offset_map(pmd, addr);
if (is_swap_pte(*pte))
pfn = swap_pte_to_pagemap_entry(*pte);
else if (pte_present(*pte))
pfn = pte_pfn(*pte);
/* unmap so we're not in atomic when we copy to userspace */
pte_unmap(pte);
err = add_to_pagemap(addr, pfn, pm);
if (err)
return err;
}
cond_resched();
return err;
}
static struct mm_walk pagemap_walk = {
.pmd_entry = pagemap_pte_range,
.pte_hole = pagemap_pte_hole
};
/*
* /proc/pid/pagemap - an array mapping virtual pages to pfns
*
* For each page in the address space, this file contains one 64-bit
* entry representing the corresponding physical page frame number
* (PFN) if the page is present. If there is a swap entry for the
* physical page, then an encoding of the swap file number and the
* page's offset into the swap file are returned. If no page is
* present at all, PM_NOT_PRESENT is returned. This allows determining
* precisely which pages are mapped (or in swap) and comparing mapped
* pages between processes.
*
* Efficient users of this interface will use /proc/pid/maps to
* determine which areas of memory are actually mapped and llseek to
* skip over unmapped regions.
*/
static ssize_t pagemap_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode);
struct page **pages, *page;
unsigned long uaddr, uend;
struct mm_struct *mm;
struct pagemapread pm;
int pagecount;
int ret = -ESRCH;
if (!task)
goto out;
ret = -EACCES;
if (!ptrace_may_attach(task))
goto out;
ret = -EINVAL;
/* file position must be aligned */
if (*ppos % PM_ENTRY_BYTES)
goto out;
ret = 0;
mm = get_task_mm(task);
if (!mm)
goto out;
ret = -ENOMEM;
uaddr = (unsigned long)buf & PAGE_MASK;
uend = (unsigned long)(buf + count);
pagecount = (PAGE_ALIGN(uend) - uaddr) / PAGE_SIZE;
pages = kmalloc(pagecount * sizeof(struct page *), GFP_KERNEL);
if (!pages)
goto out_task;
down_read(&current->mm->mmap_sem);
ret = get_user_pages(current, current->mm, uaddr, pagecount,
1, 0, pages, NULL);
up_read(&current->mm->mmap_sem);
if (ret < 0)
goto out_free;
pm.out = buf;
pm.end = buf + count;
if (!ptrace_may_attach(task)) {
ret = -EIO;
} else {
unsigned long src = *ppos;
unsigned long svpfn = src / PM_ENTRY_BYTES;
unsigned long start_vaddr = svpfn << PAGE_SHIFT;
unsigned long end_vaddr = TASK_SIZE_OF(task);
/* watch out for wraparound */
if (svpfn > TASK_SIZE_OF(task) >> PAGE_SHIFT)
start_vaddr = end_vaddr;
/*
* The odds are that this will stop walking way
* before end_vaddr, because the length of the
* user buffer is tracked in "pm", and the walk
* will stop when we hit the end of the buffer.
*/
ret = walk_page_range(mm, start_vaddr, end_vaddr,
&pagemap_walk, &pm);
if (ret == PM_END_OF_BUFFER)
ret = 0;
/* don't need mmap_sem for these, but this looks cleaner */
*ppos += pm.out - buf;
if (!ret)
ret = pm.out - buf;
}
for (; pagecount; pagecount--) {
page = pages[pagecount-1];
if (!PageReserved(page))
SetPageDirty(page);
page_cache_release(page);
}
mmput(mm);
out_free:
kfree(pages);
out_task:
put_task_struct(task);
out:
return ret;
}
const struct file_operations proc_pagemap_operations = {
.llseek = mem_lseek, /* borrow this */
.read = pagemap_read,
};
#ifdef CONFIG_NUMA
extern int show_numa_map(struct seq_file *m, void *v);
static int show_numa_map_checked(struct seq_file *m, void *v)
{
struct proc_maps_private *priv = m->private;
struct task_struct *task = priv->task;
if (maps_protect && !ptrace_may_attach(task))
return -EACCES;
return show_numa_map(m, v);
}
static struct seq_operations proc_pid_numa_maps_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_numa_map_checked
};
static int numa_maps_open(struct inode *inode, struct file *file)
{
return do_maps_open(inode, file, &proc_pid_numa_maps_op);
}
const struct file_operations proc_numa_maps_operations = {
.open = numa_maps_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
#endif