Currently, nonlinear mappings can not be distinguished from ordinary mappings.
This patch adds into /proc/pid/smaps line "Nonlinear: <size> kB", where size is
amount of nonlinear ptes in vma, this line appears only if VM_NONLINEAR is set.
This information may be useful not only for checkpoint/restore project.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx>
Requested-by: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
---
fs/proc/task_mmu.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index acee5fd..b1d9729 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -393,6 +393,7 @@ struct mem_size_stats {
unsigned long anonymous;
unsigned long anonymous_thp;
unsigned long swap;
+ unsigned long nonlinear;
u64 pss;
};
@@ -402,6 +403,7 @@ static void smaps_pte_entry(pte_t ptent, unsigned long addr,
{
struct mem_size_stats *mss = walk->private;
struct vm_area_struct *vma = mss->vma;
+ pgoff_t pgoff = linear_page_index(vma, addr);
struct page *page = NULL;
int mapcount;
@@ -414,6 +416,9 @@ static void smaps_pte_entry(pte_t ptent, unsigned long addr,
mss->swap += ptent_size;
else if (is_migration_entry(swpent))
page = migration_entry_to_page(swpent);
+ } else if (pte_file(ptent)) {
+ if (pte_to_pgoff(ptent) != pgoff)
+ mss->nonlinear += ptent_size;
}
if (!page)
@@ -422,6 +427,9 @@ static void smaps_pte_entry(pte_t ptent, unsigned long addr,
if (PageAnon(page))
mss->anonymous += ptent_size;
+ if (page->index != pgoff)
+ mss->nonlinear += ptent_size;
+
mss->resident += ptent_size;
/* Accumulate the size in pages that have been accessed. */
if (pte_young(ptent) || PageReferenced(page))
@@ -523,6 +531,10 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
(vma->vm_flags & VM_LOCKED) ?
(unsigned long)(mss.pss >> (10 + PSS_SHIFT)) : 0);
+ if (vma->vm_flags & VM_NONLINEAR)
+ seq_printf(m, "Nonlinear: %8lu kB\n",
+ mss.nonlinear >> 10);
+
if (m->count < m->size) /* vma is copied successfully */
m->version = (vma != get_gate_vma(task->mm))
? vma->vm_start : 0;
--
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