Commit 05bb6f4e authored by Oscar Salvador's avatar Oscar Salvador Committed by Andrew Morton
Browse files

mm,page_owner: filter out stacks by a threshold 

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.

Link: https://lkml.kernel.org/r/20240215215907.20121-7-osalvador@suse.de


Signed-off-by: default avatarOscar Salvador <osalvador@suse.de>
Reviewed-by: default avatarVlastimil Babka <vbabka@suse.cz>
Acked-by: default avatarAndrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 765973a0

mm/page_owner.c

+22 −1
Original line number Diff line number Diff line
@@ -846,6 +846,8 @@ 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, stack_count;
@@ -858,7 +860,8 @@ static int stack_print(struct seq_file *m, void *v) 
	entries = stack_record->entries;

	stack_count = refcount_read(&stack_record->count) - 1;



	if (!nr_entries || nr_entries < 0 || stack_count < 1)

	if (!nr_entries || nr_entries < 0 || stack_count < 1 ||

	    stack_count < page_owner_stack_threshold)

		return 0;



	for (i = 0; i < nr_entries; i++)
@@ -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;

}