226 lines · python
1#!/usr/bin/env drgn2#3# Copyright (C) 2020 Roman Gushchin <guro@fb.com>4# Copyright (C) 2020 Facebook5 6from os import stat7import argparse8import sys9 10from drgn.helpers.linux import list_for_each_entry, list_empty11from drgn.helpers.linux import for_each_page12from drgn.helpers.linux.cpumask import for_each_online_cpu13from drgn.helpers.linux.percpu import per_cpu_ptr14from drgn import container_of, FaultError, Object, cast15 16 17DESC = """18This is a drgn script to provide slab statistics for memory cgroups.19It supports cgroup v2 and v1 and can emulate memory.kmem.slabinfo20interface of cgroup v1.21For drgn, visit https://github.com/osandov/drgn.22"""23 24 25MEMCGS = {}26 27OO_SHIFT = 1628OO_MASK = ((1 << OO_SHIFT) - 1)29 30 31def err(s):32 print('slabinfo.py: error: %s' % s, file=sys.stderr, flush=True)33 sys.exit(1)34 35 36def find_memcg_ids(css=prog['root_mem_cgroup'].css, prefix=''):37 if not list_empty(css.children.address_of_()):38 for css in list_for_each_entry('struct cgroup_subsys_state',39 css.children.address_of_(),40 'sibling'):41 name = prefix + '/' + css.cgroup.kn.name.string_().decode('utf-8')42 memcg = container_of(css, 'struct mem_cgroup', 'css')43 MEMCGS[css.cgroup.kn.id.value_()] = memcg44 find_memcg_ids(css, name)45 46 47def is_root_cache(s):48 try:49 return False if s.memcg_params.root_cache else True50 except AttributeError:51 return True52 53 54def cache_name(s):55 if is_root_cache(s):56 return s.name.string_().decode('utf-8')57 else:58 return s.memcg_params.root_cache.name.string_().decode('utf-8')59 60 61# SLUB62 63def oo_order(s):64 return s.oo.x >> OO_SHIFT65 66 67def oo_objects(s):68 return s.oo.x & OO_MASK69 70 71def count_partial(n, fn):72 nr_objs = 073 for slab in list_for_each_entry('struct slab', n.partial.address_of_(),74 'slab_list'):75 nr_objs += fn(slab)76 return nr_objs77 78 79def count_free(slab):80 return slab.objects - slab.inuse81 82 83def slub_get_slabinfo(s, cfg):84 nr_slabs = 085 nr_objs = 086 nr_free = 087 88 for node in range(cfg['nr_nodes']):89 n = s.node[node]90 nr_slabs += n.nr_slabs.counter.value_()91 nr_objs += n.total_objects.counter.value_()92 nr_free += count_partial(n, count_free)93 94 return {'active_objs': nr_objs - nr_free,95 'num_objs': nr_objs,96 'active_slabs': nr_slabs,97 'num_slabs': nr_slabs,98 'objects_per_slab': oo_objects(s),99 'cache_order': oo_order(s),100 'limit': 0,101 'batchcount': 0,102 'shared': 0,103 'shared_avail': 0}104 105 106def cache_show(s, cfg, objs):107 if cfg['allocator'] == 'SLUB':108 sinfo = slub_get_slabinfo(s, cfg)109 else:110 err('SLAB isn\'t supported yet')111 112 if cfg['shared_slab_pages']:113 sinfo['active_objs'] = objs114 sinfo['num_objs'] = objs115 116 print('%-17s %6lu %6lu %6u %4u %4d'117 ' : tunables %4u %4u %4u'118 ' : slabdata %6lu %6lu %6lu' % (119 cache_name(s), sinfo['active_objs'], sinfo['num_objs'],120 s.size, sinfo['objects_per_slab'], 1 << sinfo['cache_order'],121 sinfo['limit'], sinfo['batchcount'], sinfo['shared'],122 sinfo['active_slabs'], sinfo['num_slabs'],123 sinfo['shared_avail']))124 125 126def detect_kernel_config():127 cfg = {}128 129 cfg['nr_nodes'] = prog['nr_online_nodes'].value_()130 131 if prog.type('struct kmem_cache').members[1].name == 'flags':132 cfg['allocator'] = 'SLUB'133 elif prog.type('struct kmem_cache').members[1].name == 'batchcount':134 cfg['allocator'] = 'SLAB'135 else:136 err('Can\'t determine the slab allocator')137 138 cfg['shared_slab_pages'] = False139 try:140 if prog.type('struct obj_cgroup'):141 cfg['shared_slab_pages'] = True142 except:143 pass144 145 return cfg146 147 148def for_each_slab(prog):149 PGSlab = ~prog.constant('PG_slab')150 151 for page in for_each_page(prog):152 try:153 if page.page_type.value_() == PGSlab:154 yield cast('struct slab *', page)155 except FaultError:156 pass157 158 159def main():160 parser = argparse.ArgumentParser(description=DESC,161 formatter_class=162 argparse.RawTextHelpFormatter)163 parser.add_argument('cgroup', metavar='CGROUP',164 help='Target memory cgroup')165 args = parser.parse_args()166 167 try:168 cgroup_id = stat(args.cgroup).st_ino169 find_memcg_ids()170 memcg = MEMCGS[cgroup_id]171 except KeyError:172 err('Can\'t find the memory cgroup')173 174 cfg = detect_kernel_config()175 176 print('# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>'177 ' : tunables <limit> <batchcount> <sharedfactor>'178 ' : slabdata <active_slabs> <num_slabs> <sharedavail>')179 180 if cfg['shared_slab_pages']:181 obj_cgroups = set()182 stats = {}183 caches = {}184 185 # find memcg pointers belonging to the specified cgroup186 obj_cgroups.add(memcg.objcg.value_())187 for ptr in list_for_each_entry('struct obj_cgroup',188 memcg.objcg_list.address_of_(),189 'list'):190 obj_cgroups.add(ptr.value_())191 192 # look over all slab folios and look for objects belonging193 # to the given memory cgroup194 for slab in for_each_slab(prog):195 objcg_vec_raw = slab.memcg_data.value_()196 if objcg_vec_raw == 0:197 continue198 cache = slab.slab_cache199 if not cache:200 continue201 addr = cache.value_()202 caches[addr] = cache203 # clear the lowest bit to get the true obj_cgroups204 objcg_vec = Object(prog, 'struct obj_cgroup **',205 value=objcg_vec_raw & ~1)206 207 if addr not in stats:208 stats[addr] = 0209 210 for i in range(oo_objects(cache)):211 if objcg_vec[i].value_() in obj_cgroups:212 stats[addr] += 1213 214 for addr in caches:215 if stats[addr] > 0:216 cache_show(caches[addr], cfg, stats[addr])217 218 else:219 for s in list_for_each_entry('struct kmem_cache',220 memcg.kmem_caches.address_of_(),221 'memcg_params.kmem_caches_node'):222 cache_show(s, cfg, None)223 224 225main()226