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Diffstat (limited to 'fs/proc/task_mmu.c')
-rw-r--r--fs/proc/task_mmu.c267
1 files changed, 227 insertions, 40 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 4540b8f76f16..dbf61f6174f0 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -11,6 +11,7 @@
#include <linux/rmap.h>
#include <linux/swap.h>
#include <linux/swapops.h>
+#include <linux/mmu_notifier.h>
#include <asm/elf.h>
#include <asm/uaccess.h>
@@ -54,7 +55,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
"VmPTE:\t%8lu kB\n"
"VmSwap:\t%8lu kB\n",
hiwater_vm << (PAGE_SHIFT-10),
- (total_vm - mm->reserved_vm) << (PAGE_SHIFT-10),
+ total_vm << (PAGE_SHIFT-10),
mm->locked_vm << (PAGE_SHIFT-10),
mm->pinned_vm << (PAGE_SHIFT-10),
hiwater_rss << (PAGE_SHIFT-10),
@@ -90,10 +91,55 @@ static void pad_len_spaces(struct seq_file *m, int len)
seq_printf(m, "%*c", len, ' ');
}
+#ifdef CONFIG_NUMA
+/*
+ * These functions are for numa_maps but called in generic **maps seq_file
+ * ->start(), ->stop() ops.
+ *
+ * numa_maps scans all vmas under mmap_sem and checks their mempolicy.
+ * Each mempolicy object is controlled by reference counting. The problem here
+ * is how to avoid accessing dead mempolicy object.
+ *
+ * Because we're holding mmap_sem while reading seq_file, it's safe to access
+ * each vma's mempolicy, no vma objects will never drop refs to mempolicy.
+ *
+ * A task's mempolicy (task->mempolicy) has different behavior. task->mempolicy
+ * is set and replaced under mmap_sem but unrefed and cleared under task_lock().
+ * So, without task_lock(), we cannot trust get_vma_policy() because we cannot
+ * gurantee the task never exits under us. But taking task_lock() around
+ * get_vma_plicy() causes lock order problem.
+ *
+ * To access task->mempolicy without lock, we hold a reference count of an
+ * object pointed by task->mempolicy and remember it. This will guarantee
+ * that task->mempolicy points to an alive object or NULL in numa_maps accesses.
+ */
+static void hold_task_mempolicy(struct proc_maps_private *priv)
+{
+ struct task_struct *task = priv->task;
+
+ task_lock(task);
+ priv->task_mempolicy = task->mempolicy;
+ mpol_get(priv->task_mempolicy);
+ task_unlock(task);
+}
+static void release_task_mempolicy(struct proc_maps_private *priv)
+{
+ mpol_put(priv->task_mempolicy);
+}
+#else
+static void hold_task_mempolicy(struct proc_maps_private *priv)
+{
+}
+static void release_task_mempolicy(struct proc_maps_private *priv)
+{
+}
+#endif
+
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;
+ release_task_mempolicy(priv);
up_read(&mm->mmap_sem);
mmput(mm);
}
@@ -132,7 +178,7 @@ static void *m_start(struct seq_file *m, loff_t *pos)
tail_vma = get_gate_vma(priv->task->mm);
priv->tail_vma = tail_vma;
-
+ hold_task_mempolicy(priv);
/* Start with last addr hint */
vma = find_vma(mm, last_addr);
if (last_addr && vma) {
@@ -159,6 +205,7 @@ out:
if (vma)
return vma;
+ release_task_mempolicy(priv);
/* End of vmas has been reached */
m->version = (tail_vma != NULL)? 0: -1UL;
up_read(&mm->mmap_sem);
@@ -225,7 +272,7 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
const char *name = NULL;
if (file) {
- struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
+ struct inode *inode = file_inode(vma->vm_file);
dev = inode->i_sb->s_dev;
ino = inode->i_ino;
pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
@@ -480,6 +527,57 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
return 0;
}
+static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
+{
+ /*
+ * Don't forget to update Documentation/ on changes.
+ */
+ static const char mnemonics[BITS_PER_LONG][2] = {
+ /*
+ * In case if we meet a flag we don't know about.
+ */
+ [0 ... (BITS_PER_LONG-1)] = "??",
+
+ [ilog2(VM_READ)] = "rd",
+ [ilog2(VM_WRITE)] = "wr",
+ [ilog2(VM_EXEC)] = "ex",
+ [ilog2(VM_SHARED)] = "sh",
+ [ilog2(VM_MAYREAD)] = "mr",
+ [ilog2(VM_MAYWRITE)] = "mw",
+ [ilog2(VM_MAYEXEC)] = "me",
+ [ilog2(VM_MAYSHARE)] = "ms",
+ [ilog2(VM_GROWSDOWN)] = "gd",
+ [ilog2(VM_PFNMAP)] = "pf",
+ [ilog2(VM_DENYWRITE)] = "dw",
+ [ilog2(VM_LOCKED)] = "lo",
+ [ilog2(VM_IO)] = "io",
+ [ilog2(VM_SEQ_READ)] = "sr",
+ [ilog2(VM_RAND_READ)] = "rr",
+ [ilog2(VM_DONTCOPY)] = "dc",
+ [ilog2(VM_DONTEXPAND)] = "de",
+ [ilog2(VM_ACCOUNT)] = "ac",
+ [ilog2(VM_NORESERVE)] = "nr",
+ [ilog2(VM_HUGETLB)] = "ht",
+ [ilog2(VM_NONLINEAR)] = "nl",
+ [ilog2(VM_ARCH_1)] = "ar",
+ [ilog2(VM_DONTDUMP)] = "dd",
+ [ilog2(VM_MIXEDMAP)] = "mm",
+ [ilog2(VM_HUGEPAGE)] = "hg",
+ [ilog2(VM_NOHUGEPAGE)] = "nh",
+ [ilog2(VM_MERGEABLE)] = "mg",
+ };
+ size_t i;
+
+ seq_puts(m, "VmFlags: ");
+ for (i = 0; i < BITS_PER_LONG; i++) {
+ if (vma->vm_flags & (1UL << i)) {
+ seq_printf(m, "%c%c ",
+ mnemonics[i][0], mnemonics[i][1]);
+ }
+ }
+ seq_putc(m, '\n');
+}
+
static int show_smap(struct seq_file *m, void *v, int is_pid)
{
struct proc_maps_private *priv = m->private;
@@ -535,6 +633,8 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
seq_printf(m, "Nonlinear: %8lu kB\n",
mss.nonlinear >> 10);
+ show_smap_vma_flags(m, vma);
+
if (m->count < m->size) /* vma is copied successfully */
m->version = (vma != get_gate_vma(task->mm))
? vma->vm_start : 0;
@@ -589,15 +689,63 @@ const struct file_operations proc_tid_smaps_operations = {
.release = seq_release_private,
};
+/*
+ * We do not want to have constant page-shift bits sitting in
+ * pagemap entries and are about to reuse them some time soon.
+ *
+ * Here's the "migration strategy":
+ * 1. when the system boots these bits remain what they are,
+ * but a warning about future change is printed in log;
+ * 2. once anyone clears soft-dirty bits via clear_refs file,
+ * these flag is set to denote, that user is aware of the
+ * new API and those page-shift bits change their meaning.
+ * The respective warning is printed in dmesg;
+ * 3. In a couple of releases we will remove all the mentions
+ * of page-shift in pagemap entries.
+ */
+
+static bool soft_dirty_cleared __read_mostly;
+
+enum clear_refs_types {
+ CLEAR_REFS_ALL = 1,
+ CLEAR_REFS_ANON,
+ CLEAR_REFS_MAPPED,
+ CLEAR_REFS_SOFT_DIRTY,
+ CLEAR_REFS_LAST,
+};
+
+struct clear_refs_private {
+ struct vm_area_struct *vma;
+ enum clear_refs_types type;
+};
+
+static inline void clear_soft_dirty(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *pte)
+{
+#ifdef CONFIG_MEM_SOFT_DIRTY
+ /*
+ * The soft-dirty tracker uses #PF-s to catch writes
+ * to pages, so write-protect the pte as well. See the
+ * Documentation/vm/soft-dirty.txt for full description
+ * of how soft-dirty works.
+ */
+ pte_t ptent = *pte;
+ ptent = pte_wrprotect(ptent);
+ ptent = pte_clear_flags(ptent, _PAGE_SOFT_DIRTY);
+ set_pte_at(vma->vm_mm, addr, pte, ptent);
+#endif
+}
+
static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
unsigned long end, struct mm_walk *walk)
{
- struct vm_area_struct *vma = walk->private;
+ struct clear_refs_private *cp = walk->private;
+ struct vm_area_struct *vma = cp->vma;
pte_t *pte, ptent;
spinlock_t *ptl;
struct page *page;
- split_huge_page_pmd(walk->mm, pmd);
+ split_huge_page_pmd(vma, addr, pmd);
if (pmd_trans_unstable(pmd))
return 0;
@@ -607,6 +755,11 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
if (!pte_present(ptent))
continue;
+ if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
+ clear_soft_dirty(vma, addr, pte);
+ continue;
+ }
+
page = vm_normal_page(vma, addr, ptent);
if (!page)
continue;
@@ -620,10 +773,6 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
return 0;
}
-#define CLEAR_REFS_ALL 1
-#define CLEAR_REFS_ANON 2
-#define CLEAR_REFS_MAPPED 3
-
static ssize_t clear_refs_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
@@ -631,7 +780,8 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
char buffer[PROC_NUMBUF];
struct mm_struct *mm;
struct vm_area_struct *vma;
- int type;
+ enum clear_refs_types type;
+ int itype;
int rv;
memset(buffer, 0, sizeof(buffer));
@@ -639,23 +789,37 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count))
return -EFAULT;
- rv = kstrtoint(strstrip(buffer), 10, &type);
+ rv = kstrtoint(strstrip(buffer), 10, &itype);
if (rv < 0)
return rv;
- if (type < CLEAR_REFS_ALL || type > CLEAR_REFS_MAPPED)
+ type = (enum clear_refs_types)itype;
+ if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
return -EINVAL;
- task = get_proc_task(file->f_path.dentry->d_inode);
+
+ if (type == CLEAR_REFS_SOFT_DIRTY) {
+ soft_dirty_cleared = true;
+ pr_warn_once("The pagemap bits 55-60 has changed their meaning! "
+ "See the linux/Documentation/vm/pagemap.txt for details.\n");
+ }
+
+ task = get_proc_task(file_inode(file));
if (!task)
return -ESRCH;
mm = get_task_mm(task);
if (mm) {
+ struct clear_refs_private cp = {
+ .type = type,
+ };
struct mm_walk clear_refs_walk = {
.pmd_entry = clear_refs_pte_range,
.mm = mm,
+ .private = &cp,
};
down_read(&mm->mmap_sem);
+ if (type == CLEAR_REFS_SOFT_DIRTY)
+ mmu_notifier_invalidate_range_start(mm, 0, -1);
for (vma = mm->mmap; vma; vma = vma->vm_next) {
- clear_refs_walk.private = vma;
+ cp.vma = vma;
if (is_vm_hugetlb_page(vma))
continue;
/*
@@ -674,6 +838,8 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
walk_page_range(vma->vm_start, vma->vm_end,
&clear_refs_walk);
}
+ if (type == CLEAR_REFS_SOFT_DIRTY)
+ mmu_notifier_invalidate_range_end(mm, 0, -1);
flush_tlb_mm(mm);
up_read(&mm->mmap_sem);
mmput(mm);
@@ -695,6 +861,7 @@ typedef struct {
struct pagemapread {
int pos, len;
pagemap_entry_t *buffer;
+ bool v2;
};
#define PAGEMAP_WALK_SIZE (PMD_SIZE)
@@ -708,14 +875,17 @@ struct pagemapread {
#define PM_PSHIFT_BITS 6
#define PM_PSHIFT_OFFSET (PM_STATUS_OFFSET - PM_PSHIFT_BITS)
#define PM_PSHIFT_MASK (((1LL << PM_PSHIFT_BITS) - 1) << PM_PSHIFT_OFFSET)
-#define PM_PSHIFT(x) (((u64) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK)
+#define __PM_PSHIFT(x) (((u64) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK)
#define PM_PFRAME_MASK ((1LL << PM_PSHIFT_OFFSET) - 1)
#define PM_PFRAME(x) ((x) & PM_PFRAME_MASK)
+/* in "new" pagemap pshift bits are occupied with more status bits */
+#define PM_STATUS2(v2, x) (__PM_PSHIFT(v2 ? x : PAGE_SHIFT))
+#define __PM_SOFT_DIRTY (1LL)
#define PM_PRESENT PM_STATUS(4LL)
#define PM_SWAP PM_STATUS(2LL)
#define PM_FILE PM_STATUS(1LL)
-#define PM_NOT_PRESENT PM_PSHIFT(PAGE_SHIFT)
+#define PM_NOT_PRESENT(v2) PM_STATUS2(v2, 0)
#define PM_END_OF_BUFFER 1
static inline pagemap_entry_t make_pme(u64 val)
@@ -738,7 +908,7 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end,
struct pagemapread *pm = walk->private;
unsigned long addr;
int err = 0;
- pagemap_entry_t pme = make_pme(PM_NOT_PRESENT);
+ pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2));
for (addr = start; addr < end; addr += PAGE_SIZE) {
err = add_to_pagemap(addr, &pme, pm);
@@ -748,11 +918,12 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end,
return err;
}
-static void pte_to_pagemap_entry(pagemap_entry_t *pme,
+static void pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
struct vm_area_struct *vma, unsigned long addr, pte_t pte)
{
u64 frame, flags;
struct page *page = NULL;
+ int flags2 = 0;
if (pte_present(pte)) {
frame = pte_pfn(pte);
@@ -767,19 +938,21 @@ static void pte_to_pagemap_entry(pagemap_entry_t *pme,
if (is_migration_entry(entry))
page = migration_entry_to_page(entry);
} else {
- *pme = make_pme(PM_NOT_PRESENT);
+ *pme = make_pme(PM_NOT_PRESENT(pm->v2));
return;
}
if (page && !PageAnon(page))
flags |= PM_FILE;
+ if (pte_soft_dirty(pte))
+ flags2 |= __PM_SOFT_DIRTY;
- *pme = make_pme(PM_PFRAME(frame) | PM_PSHIFT(PAGE_SHIFT) | flags);
+ *pme = make_pme(PM_PFRAME(frame) | PM_STATUS2(pm->v2, flags2) | flags);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme,
- pmd_t pmd, int offset)
+static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
+ pmd_t pmd, int offset, int pmd_flags2)
{
/*
* Currently pmd for thp is always present because thp can not be
@@ -788,13 +961,13 @@ static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme,
*/
if (pmd_present(pmd))
*pme = make_pme(PM_PFRAME(pmd_pfn(pmd) + offset)
- | PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT);
+ | PM_STATUS2(pm->v2, pmd_flags2) | PM_PRESENT);
else
- *pme = make_pme(PM_NOT_PRESENT);
+ *pme = make_pme(PM_NOT_PRESENT(pm->v2));
}
#else
-static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme,
- pmd_t pmd, int offset)
+static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
+ pmd_t pmd, int offset, int pmd_flags2)
{
}
#endif
@@ -806,17 +979,20 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
struct pagemapread *pm = walk->private;
pte_t *pte;
int err = 0;
- pagemap_entry_t pme = make_pme(PM_NOT_PRESENT);
+ pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2));
/* find the first VMA at or above 'addr' */
vma = find_vma(walk->mm, addr);
if (vma && pmd_trans_huge_lock(pmd, vma) == 1) {
+ int pmd_flags2;
+
+ pmd_flags2 = (pmd_soft_dirty(*pmd) ? __PM_SOFT_DIRTY : 0);
for (; addr != end; addr += PAGE_SIZE) {
unsigned long offset;
offset = (addr & ~PAGEMAP_WALK_MASK) >>
PAGE_SHIFT;
- thp_pmd_to_pagemap_entry(&pme, *pmd, offset);
+ thp_pmd_to_pagemap_entry(&pme, pm, *pmd, offset, pmd_flags2);
err = add_to_pagemap(addr, &pme, pm);
if (err)
break;
@@ -833,7 +1009,7 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
* and need a new, higher one */
if (vma && (addr >= vma->vm_end)) {
vma = find_vma(walk->mm, addr);
- pme = make_pme(PM_NOT_PRESENT);
+ pme = make_pme(PM_NOT_PRESENT(pm->v2));
}
/* check that 'vma' actually covers this address,
@@ -841,7 +1017,7 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
if (vma && (vma->vm_start <= addr) &&
!is_vm_hugetlb_page(vma)) {
pte = pte_offset_map(pmd, addr);
- pte_to_pagemap_entry(&pme, vma, addr, *pte);
+ pte_to_pagemap_entry(&pme, pm, vma, addr, *pte);
/* unmap before userspace copy */
pte_unmap(pte);
}
@@ -856,14 +1032,14 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
}
#ifdef CONFIG_HUGETLB_PAGE
-static void huge_pte_to_pagemap_entry(pagemap_entry_t *pme,
+static void huge_pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
pte_t pte, int offset)
{
if (pte_present(pte))
*pme = make_pme(PM_PFRAME(pte_pfn(pte) + offset)
- | PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT);
+ | PM_STATUS2(pm->v2, 0) | PM_PRESENT);
else
- *pme = make_pme(PM_NOT_PRESENT);
+ *pme = make_pme(PM_NOT_PRESENT(pm->v2));
}
/* This function walks within one hugetlb entry in the single call */
@@ -877,7 +1053,7 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
for (; addr != end; addr += PAGE_SIZE) {
int offset = (addr & ~hmask) >> PAGE_SHIFT;
- huge_pte_to_pagemap_entry(&pme, *pte, offset);
+ huge_pte_to_pagemap_entry(&pme, pm, *pte, offset);
err = add_to_pagemap(addr, &pme, pm);
if (err)
return err;
@@ -916,7 +1092,7 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
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 task_struct *task = get_proc_task(file_inode(file));
struct mm_struct *mm;
struct pagemapread pm;
int ret = -ESRCH;
@@ -939,6 +1115,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
if (!count)
goto out_task;
+ pm.v2 = soft_dirty_cleared;
pm.len = PM_ENTRY_BYTES * (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
pm.buffer = kmalloc(pm.len, GFP_TEMPORARY);
ret = -ENOMEM;
@@ -1011,9 +1188,18 @@ out:
return ret;
}
+static int pagemap_open(struct inode *inode, struct file *file)
+{
+ pr_warn_once("Bits 55-60 of /proc/PID/pagemap entries are about "
+ "to stop being page-shift some time soon. See the "
+ "linux/Documentation/vm/pagemap.txt for details.\n");
+ return 0;
+}
+
const struct file_operations proc_pagemap_operations = {
.llseek = mem_lseek, /* borrow this */
.read = pagemap_read,
+ .open = pagemap_open,
};
#endif /* CONFIG_PROC_PAGE_MONITOR */
@@ -1080,7 +1266,7 @@ static struct page *can_gather_numa_stats(pte_t pte, struct vm_area_struct *vma,
return NULL;
nid = page_to_nid(page);
- if (!node_isset(nid, node_states[N_HIGH_MEMORY]))
+ if (!node_isset(nid, node_states[N_MEMORY]))
return NULL;
return page;
@@ -1158,6 +1344,7 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
struct vm_area_struct *vma = v;
struct numa_maps *md = &numa_priv->md;
struct file *file = vma->vm_file;
+ struct task_struct *task = proc_priv->task;
struct mm_struct *mm = vma->vm_mm;
struct mm_walk walk = {};
struct mempolicy *pol;
@@ -1177,8 +1364,8 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
walk.private = md;
walk.mm = mm;
- pol = get_vma_policy(proc_priv->task, vma, vma->vm_start);
- mpol_to_str(buffer, sizeof(buffer), pol, 0);
+ pol = get_vma_policy(task, vma, vma->vm_start);
+ mpol_to_str(buffer, sizeof(buffer), pol);
mpol_cond_put(pol);
seq_printf(m, "%08lx %s", vma->vm_start, buffer);
@@ -1189,7 +1376,7 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
} else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {
seq_printf(m, " heap");
} else {
- pid_t tid = vm_is_stack(proc_priv->task, vma, is_pid);
+ pid_t tid = vm_is_stack(task, vma, is_pid);
if (tid != 0) {
/*
* Thread stack in /proc/PID/task/TID/maps or
@@ -1232,7 +1419,7 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
if (md->writeback)
seq_printf(m, " writeback=%lu", md->writeback);
- for_each_node_state(n, N_HIGH_MEMORY)
+ for_each_node_state(n, N_MEMORY)
if (md->node[n])
seq_printf(m, " N%d=%lu", n, md->node[n]);
out: