1#!/usr/bin/env drgn 2# 3# Copyright (C) 2020 Roman Gushchin <guro@fb.com> 4# Copyright (C) 2020 Facebook 5 6from os import stat 7import argparse 8import sys 9 10from drgn.helpers.linux import list_for_each_entry, list_empty 11from drgn.helpers.linux import for_each_page 12from drgn.helpers.linux.cpumask import for_each_online_cpu 13from drgn.helpers.linux.percpu import per_cpu_ptr 14from drgn import container_of, FaultError, Object, cast 15 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.slabinfo 20interface of cgroup v1. 21For drgn, visit https://github.com/osandov/drgn. 22""" 23 24 25MEMCGS = {} 26 27OO_SHIFT = 16 28OO_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_()] = memcg 44 find_memcg_ids(css, name) 45 46 47def is_root_cache(s): 48 try: 49 return False if s.memcg_params.root_cache else True 50 except AttributeError: 51 return True 52 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# SLUB 62 63def oo_order(s): 64 return s.oo.x >> OO_SHIFT 65 66 67def oo_objects(s): 68 return s.oo.x & OO_MASK 69 70 71def count_partial(n, fn): 72 nr_objs = 0 73 for slab in list_for_each_entry('struct slab', n.partial.address_of_(), 74 'slab_list'): 75 nr_objs += fn(slab) 76 return nr_objs 77 78 79def count_free(slab): 80 return slab.objects - slab.inuse 81 82 83def slub_get_slabinfo(s, cfg): 84 nr_slabs = 0 85 nr_objs = 0 86 nr_free = 0 87 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'] = objs 114 sinfo['num_objs'] = objs 115 116 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'] = False 139 try: 140 if prog.type('struct obj_cgroup'): 141 cfg['shared_slab_pages'] = True 142 except: 143 pass 144 145 return cfg 146 147 148def for_each_slab(prog): 149 PGSlab = 1 << prog.constant('PG_slab') 150 PGHead = 1 << prog.constant('PG_head') 151 152 for page in for_each_page(prog): 153 try: 154 if page.flags.value_() & PGSlab: 155 yield cast('struct slab *', page) 156 except FaultError: 157 pass 158 159 160def main(): 161 parser = argparse.ArgumentParser(description=DESC, 162 formatter_class= 163 argparse.RawTextHelpFormatter) 164 parser.add_argument('cgroup', metavar='CGROUP', 165 help='Target memory cgroup') 166 args = parser.parse_args() 167 168 try: 169 cgroup_id = stat(args.cgroup).st_ino 170 find_memcg_ids() 171 memcg = MEMCGS[cgroup_id] 172 except KeyError: 173 err('Can\'t find the memory cgroup') 174 175 cfg = detect_kernel_config() 176 177 print('# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>' 178 ' : tunables <limit> <batchcount> <sharedfactor>' 179 ' : slabdata <active_slabs> <num_slabs> <sharedavail>') 180 181 if cfg['shared_slab_pages']: 182 obj_cgroups = set() 183 stats = {} 184 caches = {} 185 186 # find memcg pointers belonging to the specified cgroup 187 obj_cgroups.add(memcg.objcg.value_()) 188 for ptr in list_for_each_entry('struct obj_cgroup', 189 memcg.objcg_list.address_of_(), 190 'list'): 191 obj_cgroups.add(ptr.value_()) 192 193 # look over all slab folios and look for objects belonging 194 # to the given memory cgroup 195 for slab in for_each_slab(prog): 196 objcg_vec_raw = slab.memcg_data.value_() 197 if objcg_vec_raw == 0: 198 continue 199 cache = slab.slab_cache 200 if not cache: 201 continue 202 addr = cache.value_() 203 caches[addr] = cache 204 # clear the lowest bit to get the true obj_cgroups 205 objcg_vec = Object(prog, 'struct obj_cgroup **', 206 value=objcg_vec_raw & ~1) 207 208 if addr not in stats: 209 stats[addr] = 0 210 211 for i in range(oo_objects(cache)): 212 if objcg_vec[i].value_() in obj_cgroups: 213 stats[addr] += 1 214 215 for addr in caches: 216 if stats[addr] > 0: 217 cache_show(caches[addr], cfg, stats[addr]) 218 219 else: 220 for s in list_for_each_entry('struct kmem_cache', 221 memcg.kmem_caches.address_of_(), 222 'memcg_params.kmem_caches_node'): 223 cache_show(s, cfg, None) 224 225 226main() 227