new file mode 100755
@@ -0,0 +1,226 @@
+#!/usr/bin/env drgn
+#
+# Copyright (C) 2020 Roman Gushchin <guro@fb.com>
+# Copyright (C) 2020 Facebook
+
+from os import stat
+import argparse
+import sys
+
+from drgn.helpers.linux import list_for_each_entry, list_empty
+from drgn.helpers.linux import for_each_page
+from drgn.helpers.linux.cpumask import for_each_online_cpu
+from drgn.helpers.linux.percpu import per_cpu_ptr
+from drgn import container_of, FaultError, Object
+
+
+DESC = """
+This is a drgn script to provide slab statistics for memory cgroups.
+It supports cgroup v2 and v1 and can emulate memory.kmem.slabinfo
+interface of cgroup v1.
+For drgn, visit https://github.com/osandov/drgn.
+"""
+
+
+MEMCGS = {}
+
+OO_SHIFT = 16
+OO_MASK = ((1 << OO_SHIFT) - 1)
+
+
+def err(s):
+ print('slabinfo.py: error: %s' % s, file=sys.stderr, flush=True)
+ sys.exit(1)
+
+
+def find_memcg_ids(css=prog['root_mem_cgroup'].css, prefix=''):
+ if not list_empty(css.children.address_of_()):
+ for css in list_for_each_entry('struct cgroup_subsys_state',
+ css.children.address_of_(),
+ 'sibling'):
+ name = prefix + '/' + css.cgroup.kn.name.string_().decode('utf-8')
+ memcg = container_of(css, 'struct mem_cgroup', 'css')
+ MEMCGS[css.cgroup.kn.id.value_()] = memcg
+ find_memcg_ids(css, name)
+
+
+def is_root_cache(s):
+ try:
+ return False if s.memcg_params.root_cache else True
+ except AttributeError:
+ return True
+
+
+def cache_name(s):
+ if is_root_cache(s):
+ return s.name.string_().decode('utf-8')
+ else:
+ return s.memcg_params.root_cache.name.string_().decode('utf-8')
+
+
+# SLUB
+
+def oo_order(s):
+ return s.oo.x >> OO_SHIFT
+
+
+def oo_objects(s):
+ return s.oo.x & OO_MASK
+
+
+def count_partial(n, fn):
+ nr_pages = 0
+ for page in list_for_each_entry('struct page', n.partial.address_of_(),
+ 'lru'):
+ nr_pages += fn(page)
+ return nr_pages
+
+
+def count_free(page):
+ return page.objects - page.inuse
+
+
+def slub_get_slabinfo(s, cfg):
+ nr_slabs = 0
+ nr_objs = 0
+ nr_free = 0
+
+ for node in range(cfg['nr_nodes']):
+ n = s.node[node]
+ nr_slabs += n.nr_slabs.counter.value_()
+ nr_objs += n.total_objects.counter.value_()
+ nr_free += count_partial(n, count_free)
+
+ return {'active_objs': nr_objs - nr_free,
+ 'num_objs': nr_objs,
+ 'active_slabs': nr_slabs,
+ 'num_slabs': nr_slabs,
+ 'objects_per_slab': oo_objects(s),
+ 'cache_order': oo_order(s),
+ 'limit': 0,
+ 'batchcount': 0,
+ 'shared': 0,
+ 'shared_avail': 0}
+
+
+def cache_show(s, cfg, objs):
+ if cfg['allocator'] == 'SLUB':
+ sinfo = slub_get_slabinfo(s, cfg)
+ else:
+ err('SLAB isn\'t supported yet')
+
+ if cfg['shared_slab_pages']:
+ sinfo['active_objs'] = objs
+ sinfo['num_objs'] = objs
+
+ print('%-17s %6lu %6lu %6u %4u %4d'
+ ' : tunables %4u %4u %4u'
+ ' : slabdata %6lu %6lu %6lu' % (
+ cache_name(s), sinfo['active_objs'], sinfo['num_objs'],
+ s.size, sinfo['objects_per_slab'], 1 << sinfo['cache_order'],
+ sinfo['limit'], sinfo['batchcount'], sinfo['shared'],
+ sinfo['active_slabs'], sinfo['num_slabs'],
+ sinfo['shared_avail']))
+
+
+def detect_kernel_config():
+ cfg = {}
+
+ cfg['nr_nodes'] = prog['nr_online_nodes'].value_()
+
+ if prog.type('struct kmem_cache').members[1][1] == 'flags':
+ cfg['allocator'] = 'SLUB'
+ elif prog.type('struct kmem_cache').members[1][1] == 'batchcount':
+ cfg['allocator'] = 'SLAB'
+ else:
+ err('Can\'t determine the slab allocator')
+
+ cfg['shared_slab_pages'] = False
+ try:
+ if prog.type('struct obj_cgroup'):
+ cfg['shared_slab_pages'] = True
+ except:
+ pass
+
+ return cfg
+
+
+def for_each_slab_page(prog):
+ PGSlab = 1 << prog.constant('PG_slab')
+ PGHead = 1 << prog.constant('PG_head')
+
+ for page in for_each_page(prog):
+ try:
+ if page.flags.value_() & PGSlab:
+ yield page
+ except FaultError:
+ pass
+
+
+def main():
+ parser = argparse.ArgumentParser(description=DESC,
+ formatter_class=
+ argparse.RawTextHelpFormatter)
+ parser.add_argument('cgroup', metavar='CGROUP',
+ help='Target memory cgroup')
+ args = parser.parse_args()
+
+ try:
+ cgroup_id = stat(args.cgroup).st_ino
+ find_memcg_ids()
+ memcg = MEMCGS[cgroup_id]
+ except KeyError:
+ err('Can\'t find the memory cgroup')
+
+ cfg = detect_kernel_config()
+
+ print('# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>'
+ ' : tunables <limit> <batchcount> <sharedfactor>'
+ ' : slabdata <active_slabs> <num_slabs> <sharedavail>')
+
+ if cfg['shared_slab_pages']:
+ obj_cgroups = set()
+ stats = {}
+ caches = {}
+
+ # find memcg pointers belonging to the specified cgroup
+ obj_cgroups.add(memcg.objcg.value_())
+ for ptr in list_for_each_entry('struct obj_cgroup',
+ memcg.objcg_list.address_of_(),
+ 'list'):
+ obj_cgroups.add(ptr.value_())
+
+ # look over all slab pages, belonging to non-root memcgs
+ # and look for objects belonging to the given memory cgroup
+ for page in for_each_slab_page(prog):
+ objcg_vec_raw = page.obj_cgroups.value_()
+ if objcg_vec_raw == 0:
+ continue
+ cache = page.slab_cache
+ if not cache:
+ continue
+ addr = cache.value_()
+ caches[addr] = cache
+ # clear the lowest bit to get the true obj_cgroups
+ objcg_vec = Object(prog, page.obj_cgroups.type_,
+ value=objcg_vec_raw & ~1)
+
+ if addr not in stats:
+ stats[addr] = 0
+
+ for i in range(oo_objects(cache)):
+ if objcg_vec[i].value_() in obj_cgroups:
+ stats[addr] += 1
+
+ for addr in caches:
+ if stats[addr] > 0:
+ cache_show(caches[addr], cfg, stats[addr])
+
+ else:
+ for s in list_for_each_entry('struct kmem_cache',
+ memcg.kmem_caches.address_of_(),
+ 'memcg_params.kmem_caches_node'):
+ cache_show(s, cfg, None)
+
+
+main()