tools/cgroup: add memcg_slabinfo.py tool
Add a drgn-based tool to display slab information for a given memcg. Can replace cgroup v1 memory.kmem.slabinfo interface on cgroup v2, but in a more flexiable way. Currently supports only SLUB configuration, but SLAB can be trivially added later. Output example: $ sudo ./tools/cgroup/memcg_slabinfo.py /sys/fs/cgroup/user.slice/user-111017.slice/user\@111017.service shmem_inode_cache 92 92 704 46 8 : tunables 0 0 0 : slabdata 2 2 0 eventpoll_pwq 56 56 72 56 1 : tunables 0 0 0 : slabdata 1 1 0 eventpoll_epi 32 32 128 32 1 : tunables 0 0 0 : slabdata 1 1 0 kmalloc-8 0 0 8 512 1 : tunables 0 0 0 : slabdata 0 0 0 kmalloc-96 0 0 96 42 1 : tunables 0 0 0 : slabdata 0 0 0 kmalloc-2048 0 0 2048 16 8 : tunables 0 0 0 : slabdata 0 0 0 kmalloc-64 128 128 64 64 1 : tunables 0 0 0 : slabdata 2 2 0 mm_struct 160 160 1024 32 8 : tunables 0 0 0 : slabdata 5 5 0 signal_cache 96 96 1024 32 8 : tunables 0 0 0 : slabdata 3 3 0 sighand_cache 45 45 2112 15 8 : tunables 0 0 0 : slabdata 3 3 0 files_cache 138 138 704 46 8 : tunables 0 0 0 : slabdata 3 3 0 task_delay_info 153 153 80 51 1 : tunables 0 0 0 : slabdata 3 3 0 task_struct 27 27 3520 9 8 : tunables 0 0 0 : slabdata 3 3 0 radix_tree_node 56 56 584 28 4 : tunables 0 0 0 : slabdata 2 2 0 btrfs_inode 140 140 1136 28 8 : tunables 0 0 0 : slabdata 5 5 0 kmalloc-1024 64 64 1024 32 8 : tunables 0 0 0 : slabdata 2 2 0 kmalloc-192 84 84 192 42 2 : tunables 0 0 0 : slabdata 2 2 0 inode_cache 54 54 600 27 4 : tunables 0 0 0 : slabdata 2 2 0 kmalloc-128 0 0 128 32 1 : tunables 0 0 0 : slabdata 0 0 0 kmalloc-512 32 32 512 32 4 : tunables 0 0 0 : slabdata 1 1 0 skbuff_head_cache 32 32 256 32 2 : tunables 0 0 0 : slabdata 1 1 0 sock_inode_cache 46 46 704 46 8 : tunables 0 0 0 : slabdata 1 1 0 cred_jar 378 378 192 42 2 : tunables 0 0 0 : slabdata 9 9 0 proc_inode_cache 96 96 672 24 4 : tunables 0 0 0 : slabdata 4 4 0 dentry 336 336 192 42 2 : tunables 0 0 0 : slabdata 8 8 0 filp 697 864 256 32 2 : tunables 0 0 0 : slabdata 27 27 0 anon_vma 644 644 88 46 1 : tunables 0 0 0 : slabdata 14 14 0 pid 1408 1408 64 64 1 : tunables 0 0 0 : slabdata 22 22 0 vm_area_struct 1200 1200 200 40 2 : tunables 0 0 0 : slabdata 30 30 0 Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Link: http://lkml.kernel.org/r/20200623174037.3951353-20-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Roman Gushchin
Linus Torvalds
parent
933dc80ec2
commit
fbc1ac9d09
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#!/usr/bin/env drgn
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#
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# Copyright (C) 2020 Roman Gushchin <guro@fb.com>
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# Copyright (C) 2020 Facebook
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from os import stat
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import argparse
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import sys
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from drgn.helpers.linux import list_for_each_entry, list_empty
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from drgn.helpers.linux import for_each_page
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from drgn.helpers.linux.cpumask import for_each_online_cpu
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from drgn.helpers.linux.percpu import per_cpu_ptr
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from drgn import container_of, FaultError, Object
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DESC = """
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This is a drgn script to provide slab statistics for memory cgroups.
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It supports cgroup v2 and v1 and can emulate memory.kmem.slabinfo
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interface of cgroup v1.
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For drgn, visit https://github.com/osandov/drgn.
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"""
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MEMCGS = {}
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OO_SHIFT = 16
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OO_MASK = ((1 << OO_SHIFT) - 1)
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def err(s):
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print('slabinfo.py: error: %s' % s, file=sys.stderr, flush=True)
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sys.exit(1)
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def find_memcg_ids(css=prog['root_mem_cgroup'].css, prefix=''):
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if not list_empty(css.children.address_of_()):
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for css in list_for_each_entry('struct cgroup_subsys_state',
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css.children.address_of_(),
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'sibling'):
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name = prefix + '/' + css.cgroup.kn.name.string_().decode('utf-8')
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memcg = container_of(css, 'struct mem_cgroup', 'css')
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MEMCGS[css.cgroup.kn.id.value_()] = memcg
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find_memcg_ids(css, name)
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def is_root_cache(s):
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try:
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return False if s.memcg_params.root_cache else True
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except AttributeError:
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return True
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def cache_name(s):
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if is_root_cache(s):
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return s.name.string_().decode('utf-8')
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else:
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return s.memcg_params.root_cache.name.string_().decode('utf-8')
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# SLUB
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def oo_order(s):
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return s.oo.x >> OO_SHIFT
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def oo_objects(s):
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return s.oo.x & OO_MASK
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def count_partial(n, fn):
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nr_pages = 0
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for page in list_for_each_entry('struct page', n.partial.address_of_(),
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'lru'):
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nr_pages += fn(page)
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return nr_pages
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def count_free(page):
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return page.objects - page.inuse
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def slub_get_slabinfo(s, cfg):
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nr_slabs = 0
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nr_objs = 0
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nr_free = 0
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for node in range(cfg['nr_nodes']):
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n = s.node[node]
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nr_slabs += n.nr_slabs.counter.value_()
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nr_objs += n.total_objects.counter.value_()
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nr_free += count_partial(n, count_free)
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return {'active_objs': nr_objs - nr_free,
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'num_objs': nr_objs,
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'active_slabs': nr_slabs,
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'num_slabs': nr_slabs,
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'objects_per_slab': oo_objects(s),
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'cache_order': oo_order(s),
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'limit': 0,
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'batchcount': 0,
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'shared': 0,
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'shared_avail': 0}
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def cache_show(s, cfg, objs):
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if cfg['allocator'] == 'SLUB':
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sinfo = slub_get_slabinfo(s, cfg)
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else:
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err('SLAB isn\'t supported yet')
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if cfg['shared_slab_pages']:
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sinfo['active_objs'] = objs
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sinfo['num_objs'] = objs
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print('%-17s %6lu %6lu %6u %4u %4d'
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' : tunables %4u %4u %4u'
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' : slabdata %6lu %6lu %6lu' % (
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cache_name(s), sinfo['active_objs'], sinfo['num_objs'],
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s.size, sinfo['objects_per_slab'], 1 << sinfo['cache_order'],
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sinfo['limit'], sinfo['batchcount'], sinfo['shared'],
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sinfo['active_slabs'], sinfo['num_slabs'],
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sinfo['shared_avail']))
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def detect_kernel_config():
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cfg = {}
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cfg['nr_nodes'] = prog['nr_online_nodes'].value_()
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if prog.type('struct kmem_cache').members[1][1] == 'flags':
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cfg['allocator'] = 'SLUB'
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elif prog.type('struct kmem_cache').members[1][1] == 'batchcount':
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cfg['allocator'] = 'SLAB'
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else:
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err('Can\'t determine the slab allocator')
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cfg['shared_slab_pages'] = False
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try:
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if prog.type('struct obj_cgroup'):
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cfg['shared_slab_pages'] = True
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except:
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pass
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return cfg
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def for_each_slab_page(prog):
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PGSlab = 1 << prog.constant('PG_slab')
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PGHead = 1 << prog.constant('PG_head')
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for page in for_each_page(prog):
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try:
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if page.flags.value_() & PGSlab:
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yield page
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except FaultError:
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pass
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def main():
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parser = argparse.ArgumentParser(description=DESC,
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formatter_class=
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argparse.RawTextHelpFormatter)
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parser.add_argument('cgroup', metavar='CGROUP',
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help='Target memory cgroup')
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args = parser.parse_args()
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try:
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cgroup_id = stat(args.cgroup).st_ino
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find_memcg_ids()
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memcg = MEMCGS[cgroup_id]
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except KeyError:
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err('Can\'t find the memory cgroup')
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cfg = detect_kernel_config()
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print('# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>'
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' : tunables <limit> <batchcount> <sharedfactor>'
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' : slabdata <active_slabs> <num_slabs> <sharedavail>')
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if cfg['shared_slab_pages']:
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obj_cgroups = set()
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stats = {}
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caches = {}
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# find memcg pointers belonging to the specified cgroup
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obj_cgroups.add(memcg.objcg.value_())
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for ptr in list_for_each_entry('struct obj_cgroup',
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memcg.objcg_list.address_of_(),
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'list'):
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obj_cgroups.add(ptr.value_())
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# look over all slab pages, belonging to non-root memcgs
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# and look for objects belonging to the given memory cgroup
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for page in for_each_slab_page(prog):
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objcg_vec_raw = page.obj_cgroups.value_()
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if objcg_vec_raw == 0:
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continue
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cache = page.slab_cache
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if not cache:
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continue
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addr = cache.value_()
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caches[addr] = cache
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# clear the lowest bit to get the true obj_cgroups
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objcg_vec = Object(prog, page.obj_cgroups.type_,
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value=objcg_vec_raw & ~1)
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if addr not in stats:
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stats[addr] = 0
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for i in range(oo_objects(cache)):
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if objcg_vec[i].value_() in obj_cgroups:
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stats[addr] += 1
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for addr in caches:
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if stats[addr] > 0:
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cache_show(caches[addr], cfg, stats[addr])
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else:
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for s in list_for_each_entry('struct kmem_cache',
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memcg.kmem_caches.address_of_(),
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'memcg_params.kmem_caches_node'):
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cache_show(s, cfg, None)
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main()
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