1#!/usr/bin/env python3
2#
3# Copyright (C) 2022 Roman Gushchin <roman.gushchin@linux.dev>
4# Copyright (C) 2022 Meta
5
6import os
7import argparse
8
9
10def scan_cgroups(cgroup_root):
11    cgroups = {}
12
13    for root, subdirs, _ in os.walk(cgroup_root):
14        for cgroup in subdirs:
15            path = os.path.join(root, cgroup)
16            ino = os.stat(path).st_ino
17            cgroups[ino] = path
18
19    # (memcg ino, path)
20    return cgroups
21
22
23def scan_shrinkers(shrinker_debugfs):
24    shrinkers = []
25
26    for root, subdirs, _ in os.walk(shrinker_debugfs):
27        for shrinker in subdirs:
28            count_path = os.path.join(root, shrinker, "count")
29            with open(count_path) as f:
30                for line in f.readlines():
31                    items = line.split(' ')
32                    ino = int(items[0])
33                    # (count, shrinker, memcg ino)
34                    shrinkers.append((int(items[1]), shrinker, ino))
35    return shrinkers
36
37
38def main():
39    parser = argparse.ArgumentParser(description='Display biggest shrinkers')
40    parser.add_argument('-n', '--lines', type=int, help='Number of lines to print')
41
42    args = parser.parse_args()
43
44    cgroups = scan_cgroups("/sys/fs/cgroup/")
45    shrinkers = scan_shrinkers("/sys/kernel/debug/shrinker/")
46    shrinkers.sort(reverse = True, key = lambda x: x[0])
47
48    n = 0
49    for s in shrinkers:
50        count, name, ino = (s[0], s[1], s[2])
51        if count == 0:
52            break
53
54        if ino == 0 or ino == 1:
55            cg = "/"
56        else:
57            try:
58                cg = cgroups[ino]
59            except KeyError:
60                cg = "unknown (%d)" % ino
61
62        print("%-8s %-20s %s" % (count, name, cg))
63
64        n += 1
65        if args.lines and n >= args.lines:
66            break
67
68
69if __name__ == '__main__':
70    main()
71