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-rw-r--r--fs/proc/task_mmu.c112
1 files changed, 106 insertions, 6 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 79827ce03e3..448455b7fd9 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -90,10 +90,55 @@ 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 +177,7 @@ 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 +204,7 @@ 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);
@@ -480,6 +526,57 @@ 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 +632,8 @@ 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;
@@ -597,7 +696,7 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
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;
@@ -1080,7 +1179,7 @@ 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 +1257,7 @@ 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;
@@ -1177,7 +1277,7 @@ 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);
+ pol = get_vma_policy(task, vma, vma->vm_start);
mpol_to_str(buffer, sizeof(buffer), pol, 0);
mpol_cond_put(pol);
@@ -1189,7 +1289,7 @@ 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 +1332,7 @@ 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:
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-04-17 11:23:59 +0000