tools/cgroup/memcg_shrinker.py

   1 #!/usr/bin/env python3
   2 #
   3 # Copyright (C) 2022 Roman Gushchin <roman.gushchin@linux.dev>
   4 # Copyright (C) 2022 Meta
   5
   6 import os
   7 import argparse
   8
   9
  10 def 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
  23 def 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
  38 def 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
  69 if __name__ == '__main__':
  70     main()