We want to be able to filter out the stacks based on a threshold we can
can tune.
By writing to 'count_threshold' file, we can adjust the threshold value.
Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
---
mm/page_owner.c | 29 +++++++++++++++++++++++++----
1 file changed, 25 insertions(+), 4 deletions(-)
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 5258a417f4d1..9b975f59b773 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -846,9 +846,11 @@ static void *stack_next(struct seq_file *m, void *v, loff_t *ppos)
return stack;
}
+static unsigned long page_owner_stack_threshold;
+
static int stack_print(struct seq_file *m, void *v)
{
- int i;
+ int i, stack_count;
struct stack *stack = v;
unsigned long *entries;
unsigned long nr_entries;
@@ -856,14 +858,15 @@ static int stack_print(struct seq_file *m, void *v)
nr_entries = stack_record->size;
entries = stack_record->entries;
+ stack_count = refcount_read(&stack_record->count);
- if (!nr_entries || nr_entries < 0 ||
- refcount_read(&stack_record->count) < 2)
+ if (!nr_entries || nr_entries < 0 || stack_count < 2 ||
+ stack_count < page_owner_stack_threshold)
return 0;
for (i = 0; i < nr_entries; i++)
seq_printf(m, " %pS\n", (void *)entries[i]);
- seq_printf(m, "stack_count: %d\n\n", refcount_read(&stack_record->count));
+ seq_printf(m, "stack_count: %d\n\n", stack_count);
return 0;
}
@@ -891,6 +894,22 @@ static const struct file_operations page_owner_stack_operations = {
.release = seq_release,
};
+static int page_owner_threshold_get(void *data, u64 *val)
+{
+ *val = READ_ONCE(page_owner_stack_threshold);
+ return 0;
+}
+
+static int page_owner_threshold_set(void *data, u64 val)
+{
+ WRITE_ONCE(page_owner_stack_threshold, val);
+ return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(proc_page_owner_threshold, &page_owner_threshold_get,
+ &page_owner_threshold_set, "%llu");
+
+
static int __init pageowner_init(void)
{
struct dentry *dir;
@@ -905,6 +924,8 @@ static int __init pageowner_init(void)
dir = debugfs_create_dir("page_owner_stacks", NULL);
debugfs_create_file("show_stacks", 0400, dir, NULL,
&page_owner_stack_operations);
+ debugfs_create_file("count_threshold", 0600, dir, NULL,
+ &proc_page_owner_threshold);
return 0;
}
--
2.43.0
