kernel-ark/fs/proc/task_mmu.c
Eric W. Biederman 99f8955183 [PATCH] proc: don't lock task_structs indefinitely
Every inode in /proc holds a reference to a struct task_struct.  If a
directory or file is opened and remains open after the the task exits this
pinning continues.  With 8K stacks on a 32bit machine the amount pinned per
file descriptor is about 10K.

Normally I would figure a reasonable per user process limit is about 100
processes.  With 80 processes, with a 1000 file descriptors each I can trigger
the 00M killer on a 32bit kernel, because I have pinned about 800MB of useless
data.

This patch replaces the struct task_struct pointer with a pointer to a struct
task_ref which has a struct task_struct pointer.  The so the pinning of dead
tasks does not happen.

The code now has to contend with the fact that the task may now exit at any
time.  Which is a little but not muh more complicated.

With this change it takes about 1000 processes each opening up 1000 file
descriptors before I can trigger the OOM killer.  Much better.

[mlp@google.com: task_mmu small fixes]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Paul Jackson <pj@sgi.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Albert Cahalan <acahalan@gmail.com>
Signed-off-by: Prasanna Meda <mlp@google.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:25 -07:00

477 lines
11 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/pagemap.h>
#include <linux/mempolicy.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_vfsmnt);
*dentry = dget(vma->vm_file->f_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, ' ');
}
struct mem_size_stats
{
unsigned long resident;
unsigned long shared_clean;
unsigned long shared_dirty;
unsigned long private_clean;
unsigned long private_dirty;
};
static int show_map_internal(struct seq_file *m, void *v, struct mem_size_stats *mss)
{
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 (file) {
struct inode *inode = vma->vm_file->f_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_vfsmnt, file->f_dentry, "\n");
} else {
if (mm) {
if (vma->vm_start <= mm->start_brk &&
vma->vm_end >= mm->brk) {
pad_len_spaces(m, len);
seq_puts(m, "[heap]");
} else {
if (vma->vm_start <= mm->start_stack &&
vma->vm_end >= mm->start_stack) {
pad_len_spaces(m, len);
seq_puts(m, "[stack]");
}
}
} else {
pad_len_spaces(m, len);
seq_puts(m, "[vdso]");
}
}
seq_putc(m, '\n');
if (mss)
seq_printf(m,
"Size: %8lu kB\n"
"Rss: %8lu kB\n"
"Shared_Clean: %8lu kB\n"
"Shared_Dirty: %8lu kB\n"
"Private_Clean: %8lu kB\n"
"Private_Dirty: %8lu kB\n",
(vma->vm_end - vma->vm_start) >> 10,
mss->resident >> 10,
mss->shared_clean >> 10,
mss->shared_dirty >> 10,
mss->private_clean >> 10,
mss->private_dirty >> 10);
if (m->count < m->size) /* vma is copied successfully */
m->version = (vma != get_gate_vma(task))? vma->vm_start: 0;
return 0;
}
static int show_map(struct seq_file *m, void *v)
{
return show_map_internal(m, v, NULL);
}
static void smaps_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long end,
struct mem_size_stats *mss)
{
pte_t *pte, ptent;
spinlock_t *ptl;
struct page *page;
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
do {
ptent = *pte;
if (!pte_present(ptent))
continue;
mss->resident += PAGE_SIZE;
page = vm_normal_page(vma, addr, ptent);
if (!page)
continue;
if (page_mapcount(page) >= 2) {
if (pte_dirty(ptent))
mss->shared_dirty += PAGE_SIZE;
else
mss->shared_clean += PAGE_SIZE;
} else {
if (pte_dirty(ptent))
mss->private_dirty += PAGE_SIZE;
else
mss->private_clean += PAGE_SIZE;
}
} while (pte++, addr += PAGE_SIZE, addr != end);
pte_unmap_unlock(pte - 1, ptl);
cond_resched();
}
static inline void smaps_pmd_range(struct vm_area_struct *vma, pud_t *pud,
unsigned long addr, unsigned long end,
struct mem_size_stats *mss)
{
pmd_t *pmd;
unsigned long next;
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
if (pmd_none_or_clear_bad(pmd))
continue;
smaps_pte_range(vma, pmd, addr, next, mss);
} while (pmd++, addr = next, addr != end);
}
static inline void smaps_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
unsigned long addr, unsigned long end,
struct mem_size_stats *mss)
{
pud_t *pud;
unsigned long next;
pud = pud_offset(pgd, addr);
do {
next = pud_addr_end(addr, end);
if (pud_none_or_clear_bad(pud))
continue;
smaps_pmd_range(vma, pud, addr, next, mss);
} while (pud++, addr = next, addr != end);
}
static inline void smaps_pgd_range(struct vm_area_struct *vma,
unsigned long addr, unsigned long end,
struct mem_size_stats *mss)
{
pgd_t *pgd;
unsigned long next;
pgd = pgd_offset(vma->vm_mm, addr);
do {
next = pgd_addr_end(addr, end);
if (pgd_none_or_clear_bad(pgd))
continue;
smaps_pud_range(vma, pgd, addr, next, mss);
} while (pgd++, addr = next, addr != end);
}
static int show_smap(struct seq_file *m, void *v)
{
struct vm_area_struct *vma = v;
struct mem_size_stats mss;
memset(&mss, 0, sizeof mss);
if (vma->vm_mm && !is_vm_hugetlb_page(vma))
smaps_pgd_range(vma, vma->vm_start, vma->vm_end, &mss);
return show_map_internal(m, v, &mss);
}
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_tref_task(priv->tref);
if (!priv->task)
return NULL;
mm = get_task_mm(priv->task);
if (!mm)
return NULL;
priv->tail_vma = tail_vma = get_gate_vma(priv->task);
down_read(&mm->mmap_sem);
/* Start with last addr hint */
if (last_addr && (vma = find_vma(mm, last_addr))) {
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 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_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 struct seq_operations proc_pid_maps_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_map
};
static struct seq_operations proc_pid_smaps_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_smap
};
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->tref = proc_tref(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 maps_open(struct inode *inode, struct file *file)
{
return do_maps_open(inode, file, &proc_pid_maps_op);
}
struct file_operations proc_maps_operations = {
.open = maps_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
#ifdef CONFIG_NUMA
extern int show_numa_map(struct seq_file *m, void *v);
static struct seq_operations proc_pid_numa_maps_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_numa_map
};
static int numa_maps_open(struct inode *inode, struct file *file)
{
return do_maps_open(inode, file, &proc_pid_numa_maps_op);
}
struct file_operations proc_numa_maps_operations = {
.open = numa_maps_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};
#endif
static int smaps_open(struct inode *inode, struct file *file)
{
return do_maps_open(inode, file, &proc_pid_smaps_op);
}
struct file_operations proc_smaps_operations = {
.open = smaps_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release_private,
};