1
linux/fs/proc/task_mmu.c
Hugh Dickins 365e9c87a9 [PATCH] mm: update_hiwaters just in time
update_mem_hiwater has attracted various criticisms, in particular from those
concerned with mm scalability.  Originally it was called whenever rss or
total_vm got raised.  Then many of those callsites were replaced by a timer
tick call from account_system_time.  Now Frank van Maarseveen reports that to
be found inadequate.  How about this?  Works for Frank.

Replace update_mem_hiwater, a poor combination of two unrelated ops, by macros
update_hiwater_rss and update_hiwater_vm.  Don't attempt to keep
mm->hiwater_rss up to date at timer tick, nor every time we raise rss (usually
by 1): those are hot paths.  Do the opposite, update only when about to lower
rss (usually by many), or just before final accounting in do_exit.  Handle
mm->hiwater_vm in the same way, though it's much less of an issue.  Demand
that whoever collects these hiwater statistics do the work of taking the
maximum with rss or total_vm.

And there has been no collector of these hiwater statistics in the tree.  The
new convention needs an example, so match Frank's usage by adding a VmPeak
line above VmSize to /proc/<pid>/status, and also a VmHWM line above VmRSS
(High-Water-Mark or High-Water-Memory).

There was a particular anomaly during mremap move, that hiwater_vm might be
captured too high.  A fleeting such anomaly remains, but it's quickly
corrected now, whereas before it would stick.

What locking?  None: if the app is racy then these statistics will be racy,
it's not worth any overhead to make them exact.  But whenever it suits,
hiwater_vm is updated under exclusive mmap_sem, and hiwater_rss under
page_table_lock (for now) or with preemption disabled (later on): without
going to any trouble, minimize the time between reading current values and
updating, to minimize those occasions when a racing thread bumps a count up
and back down in between.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:39 -07:00

526 lines
12 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 = proc_task(inode);
struct mm_struct * mm = get_task_mm(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 task_struct *task = m->private;
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, 0);
}
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;
unsigned long pfn;
struct page *page;
pte = pte_offset_map(pmd, addr);
do {
ptent = *pte;
if (pte_none(ptent) || !pte_present(ptent))
continue;
mss->resident += PAGE_SIZE;
pfn = pte_pfn(ptent);
if (!pfn_valid(pfn))
continue;
page = pfn_to_page(pfn);
if (page_count(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(pte - 1);
cond_resched_lock(&vma->vm_mm->page_table_lock);
}
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 mm_struct *mm = vma->vm_mm;
struct mem_size_stats mss;
memset(&mss, 0, sizeof mss);
if (mm) {
spin_lock(&mm->page_table_lock);
smaps_pgd_range(vma, vma->vm_start, vma->vm_end, &mss);
spin_unlock(&mm->page_table_lock);
}
return show_map_internal(m, v, &mss);
}
static void *m_start(struct seq_file *m, loff_t *pos)
{
struct task_struct *task = m->private;
unsigned long last_addr = m->version;
struct mm_struct *mm;
struct vm_area_struct *vma, *tail_vma;
loff_t l = *pos;
/*
* 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;
mm = get_task_mm(task);
if (!mm)
return NULL;
tail_vma = get_gate_vma(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 m_stop(struct seq_file *m, void *v)
{
struct task_struct *task = m->private;
struct vm_area_struct *vma = v;
if (vma && vma != get_gate_vma(task)) {
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 task_struct *task = m->private;
struct vm_area_struct *vma = v;
struct vm_area_struct *tail_vma = get_gate_vma(task);
(*pos)++;
if (vma && (vma != tail_vma) && vma->vm_next)
return vma->vm_next;
m_stop(m, v);
return (vma != tail_vma)? tail_vma: NULL;
}
struct seq_operations proc_pid_maps_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_map
};
struct seq_operations proc_pid_smaps_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_smap
};
#ifdef CONFIG_NUMA
struct numa_maps {
unsigned long pages;
unsigned long anon;
unsigned long mapped;
unsigned long mapcount_max;
unsigned long node[MAX_NUMNODES];
};
/*
* Calculate numa node maps for a vma
*/
static struct numa_maps *get_numa_maps(const struct vm_area_struct *vma)
{
struct page *page;
unsigned long vaddr;
struct mm_struct *mm = vma->vm_mm;
int i;
struct numa_maps *md = kmalloc(sizeof(struct numa_maps), GFP_KERNEL);
if (!md)
return NULL;
md->pages = 0;
md->anon = 0;
md->mapped = 0;
md->mapcount_max = 0;
for_each_node(i)
md->node[i] =0;
spin_lock(&mm->page_table_lock);
for (vaddr = vma->vm_start; vaddr < vma->vm_end; vaddr += PAGE_SIZE) {
page = follow_page(mm, vaddr, 0);
if (page) {
int count = page_mapcount(page);
if (count)
md->mapped++;
if (count > md->mapcount_max)
md->mapcount_max = count;
md->pages++;
if (PageAnon(page))
md->anon++;
md->node[page_to_nid(page)]++;
}
}
spin_unlock(&mm->page_table_lock);
return md;
}
static int show_numa_map(struct seq_file *m, void *v)
{
struct task_struct *task = m->private;
struct vm_area_struct *vma = v;
struct mempolicy *pol;
struct numa_maps *md;
struct zone **z;
int n;
int first;
if (!vma->vm_mm)
return 0;
md = get_numa_maps(vma);
if (!md)
return 0;
seq_printf(m, "%08lx", vma->vm_start);
pol = get_vma_policy(task, vma, vma->vm_start);
/* Print policy */
switch (pol->policy) {
case MPOL_PREFERRED:
seq_printf(m, " prefer=%d", pol->v.preferred_node);
break;
case MPOL_BIND:
seq_printf(m, " bind={");
first = 1;
for (z = pol->v.zonelist->zones; *z; z++) {
if (!first)
seq_putc(m, ',');
else
first = 0;
seq_printf(m, "%d/%s", (*z)->zone_pgdat->node_id,
(*z)->name);
}
seq_putc(m, '}');
break;
case MPOL_INTERLEAVE:
seq_printf(m, " interleave={");
first = 1;
for_each_node(n) {
if (node_isset(n, pol->v.nodes)) {
if (!first)
seq_putc(m,',');
else
first = 0;
seq_printf(m, "%d",n);
}
}
seq_putc(m, '}');
break;
default:
seq_printf(m," default");
break;
}
seq_printf(m, " MaxRef=%lu Pages=%lu Mapped=%lu",
md->mapcount_max, md->pages, md->mapped);
if (md->anon)
seq_printf(m," Anon=%lu",md->anon);
for_each_online_node(n) {
if (md->node[n])
seq_printf(m, " N%d=%lu", n, md->node[n]);
}
seq_putc(m, '\n');
kfree(md);
if (m->count < m->size) /* vma is copied successfully */
m->version = (vma != get_gate_vma(task)) ? vma->vm_start : 0;
return 0;
}
struct seq_operations proc_pid_numa_maps_op = {
.start = m_start,
.next = m_next,
.stop = m_stop,
.show = show_numa_map
};
#endif