LinuxLists.cc - Re: [PATCH v2 27/28] tools/cgroup: make slabinfo.py compatible with new slab controller

2020-01-30 02:20:48

Subject: Re: [PATCH v2 27/28] tools/cgroup: make slabinfo.py compatible with new slab controller

On Mon, Jan 27, 2020 at 09:34:52AM -0800, Roman Gushchin wrote:
> Make slabinfo.py compatible with the new slab controller.

Tried using slabinfo.py, but run into some errors. (I am using your
new_slab.2 branch)

./tools/cgroup/slabinfo.py /sys/fs/cgroup/memory/1
Traceback (most recent call last):
File "/usr/local/bin/drgn", line 11, in <module>
sys.exit(main())
File "/usr/local/lib/python3.6/dist-packages/drgn/internal/cli.py", line 127, in main
runpy.run_path(args.script[0], init_globals=init_globals, run_name="__main__")
File "/usr/lib/python3.6/runpy.py", line 263, in run_path
pkg_name=pkg_name, script_name=fname)
File "/usr/lib/python3.6/runpy.py", line 96, in _run_module_code
mod_name, mod_spec, pkg_name, script_name)
File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
exec(code, run_globals)
File "./tools/cgroup/slabinfo.py", line 220, in <module>
main()
File "./tools/cgroup/slabinfo.py", line 165, in main
find_memcg_ids()
File "./tools/cgroup/slabinfo.py", line 43, in find_memcg_ids
MEMCGS[css.cgroup.kn.id.ino.value_()] = memcg
AttributeError: '_drgn.Object' object has no attribute 'ino'

I did make this change...

# git diff
diff --git a/tools/cgroup/slabinfo.py b/tools/cgroup/slabinfo.py
index b779a4863beb..571fd95224d6 100755
--- a/tools/cgroup/slabinfo.py
+++ b/tools/cgroup/slabinfo.py
@@ -40,7 +40,7 @@ def find_memcg_ids(css=prog['root_mem_cgroup'].css, prefix=''):
'sibling'):
name = prefix + '/' + css.cgroup.kn.name.string_().decode('utf-8')
memcg = container_of(css, 'struct mem_cgroup', 'css')
- MEMCGS[css.cgroup.kn.id.ino.value_()] = memcg
+ MEMCGS[css.cgroup.kn.id.value_()] = memcg
find_memcg_ids(css, name)

but now get empty output.

# ./tools/cgroup/slabinfo.py /sys/fs/cgroup/memory/1
# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab> : tunables <limit> <batchcount> <sharedfactor> : slabdata <active_slabs> <num_slabs> <sharedavail>

Guess this script is not yet ready for the upstream kernel?

Regards,
Bharata.

2020-01-30 02:47:12

by Roman Gushchin

[permalink] [raw]

Subject: Re: [PATCH v2 27/28] tools/cgroup: make slabinfo.py compatible with new slab controller

2020-01-31 22:27:49

by Roman Gushchin

[permalink] [raw]

Subject: Re: [PATCH v2 27/28] tools/cgroup: make slabinfo.py compatible with new slab controller

On Thu, Jan 30, 2020 at 07:47:29AM +0530, Bharata B Rao wrote:
> On Mon, Jan 27, 2020 at 09:34:52AM -0800, Roman Gushchin wrote:
> > Make slabinfo.py compatible with the new slab controller.
>
> Tried using slabinfo.py, but run into some errors. (I am using your
> new_slab.2 branch)
>
> ./tools/cgroup/slabinfo.py /sys/fs/cgroup/memory/1
> Traceback (most recent call last):
> File "/usr/local/bin/drgn", line 11, in <module>
> sys.exit(main())
> File "/usr/local/lib/python3.6/dist-packages/drgn/internal/cli.py", line 127, in main
> runpy.run_path(args.script[0], init_globals=init_globals, run_name="__main__")
> File "/usr/lib/python3.6/runpy.py", line 263, in run_path
> pkg_name=pkg_name, script_name=fname)
> File "/usr/lib/python3.6/runpy.py", line 96, in _run_module_code
> mod_name, mod_spec, pkg_name, script_name)
> File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
> exec(code, run_globals)
> File "./tools/cgroup/slabinfo.py", line 220, in <module>
> main()
> File "./tools/cgroup/slabinfo.py", line 165, in main
> find_memcg_ids()
> File "./tools/cgroup/slabinfo.py", line 43, in find_memcg_ids
> MEMCGS[css.cgroup.kn.id.ino.value_()] = memcg
> AttributeError: '_drgn.Object' object has no attribute 'ino'
>
> I did make this change...
>
> # git diff
> diff --git a/tools/cgroup/slabinfo.py b/tools/cgroup/slabinfo.py
> index b779a4863beb..571fd95224d6 100755
> --- a/tools/cgroup/slabinfo.py
> +++ b/tools/cgroup/slabinfo.py
> @@ -40,7 +40,7 @@ def find_memcg_ids(css=prog['root_mem_cgroup'].css, prefix=''):
> 'sibling'):
> name = prefix + '/' + css.cgroup.kn.name.string_().decode('utf-8')
> memcg = container_of(css, 'struct mem_cgroup', 'css')
> - MEMCGS[css.cgroup.kn.id.ino.value_()] = memcg
> + MEMCGS[css.cgroup.kn.id.value_()] = memcg
> find_memcg_ids(css, name)
>
>
> but now get empty output.

Btw, I've checked that the change like you've done above fixes the problem.
The script works for me both on current upstream and new_slab.2 branch.

Are you sure that in your case there is some kernel memory charged to that
cgroup? Please note, that in the current implementation kmem_caches are created
on demand, so the accounting is effectively enabled with some delay.

Thank you!

Below is an updated version of the patch to use:
--------------------------------------------------------------------------------

From 69b8e1bf451043c41e43e769b9ae15b36092ddf9 Mon Sep 17 00:00:00 2001
From: Roman Gushchin <[email protected]>
Date: Tue, 15 Oct 2019 17:06:04 -0700
Subject: [PATCH v2 26/28] tools/cgroup: add 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/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 <[email protected]>
Cc: Waiman Long <[email protected]>
Cc: Tobin C. Harding <[email protected]>
Cc: Tejun Heo <[email protected]>
---
tools/cgroup/slabinfo.py | 158 +++++++++++++++++++++++++++++++++++++++
1 file changed, 158 insertions(+)
create mode 100755 tools/cgroup/slabinfo.py

diff --git a/tools/cgroup/slabinfo.py b/tools/cgroup/slabinfo.py
new file mode 100755
index 000000000000..0dc3a1fc260c
--- /dev/null
+++ b/tools/cgroup/slabinfo.py
@@ -0,0 +1,158 @@
+#!/usr/bin/env drgn
+#
+# Copyright (C) 2019 Roman Gushchin <[email protected]>
+# Copyright (C) 2019 Facebook
+
+from os import stat
+import argparse
+import sys
+
+from drgn.helpers.linux import list_for_each_entry, list_empty
+from drgn import container_of
+
+
+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):
+ return False if s.memcg_params.root_cache else 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):
+ if cfg['allocator'] == 'SLUB':
+ sinfo = slub_get_slabinfo(s, cfg)
+ else:
+ err('SLAB isn\'t supported yet')
+
+ 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')
+
+ return cfg
+
+
+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>')
+
+ for s in list_for_each_entry('struct kmem_cache',
+ memcg.kmem_caches.address_of_(),
+ 'memcg_params.kmem_caches_node'):
+ cache_show(s, cfg)
+
+
+main()
--
2.24.1

2020-02-12 05:22:32

by Bharata B Rao

[permalink] [raw]

Subject: Re: [PATCH v2 27/28] tools/cgroup: make slabinfo.py compatible with new slab controller

On Fri, Jan 31, 2020 at 10:24:58PM +0000, Roman Gushchin wrote:
> On Thu, Jan 30, 2020 at 07:47:29AM +0530, Bharata B Rao wrote:
> > On Mon, Jan 27, 2020 at 09:34:52AM -0800, Roman Gushchin wrote:
>
> Btw, I've checked that the change like you've done above fixes the problem.
> The script works for me both on current upstream and new_slab.2 branch.
>
> Are you sure that in your case there is some kernel memory charged to that
> cgroup? Please note, that in the current implementation kmem_caches are created
> on demand, so the accounting is effectively enabled with some delay.

I do see kmem getting charged.

# cat /sys/fs/cgroup/memory/1/memory.kmem.usage_in_bytes /sys/fs/cgroup/memory/1/memory.usage_in_bytes
182910976
4515627008

> Below is an updated version of the patch to use:

I see the below failure with this updated version:

# ./tools/cgroup/slabinfo-new.py /sys/fs/cgroup/memory/1
# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab> : tunables <limit> <batchcount> <sharedfactor> : slabdata <active_slabs> <num_slabs> <sharedavail>
Traceback (most recent call last):
File "/usr/local/bin/drgn", line 11, in <module>
sys.exit(main())
File "/usr/local/lib/python3.6/dist-packages/drgn/internal/cli.py", line 127, in main
runpy.run_path(args.script[0], init_globals=init_globals, run_name="__main__")
File "/usr/lib/python3.6/runpy.py", line 263, in run_path
pkg_name=pkg_name, script_name=fname)
File "/usr/lib/python3.6/runpy.py", line 96, in _run_module_code
mod_name, mod_spec, pkg_name, script_name)
File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
exec(code, run_globals)
File "./tools/cgroup/slabinfo-new.py", line 158, in <module>
main()
File "./tools/cgroup/slabinfo-new.py", line 153, in main
memcg.kmem_caches.address_of_(),
AttributeError: 'struct mem_cgroup' has no member 'kmem_caches'

> +
> +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>')
> +
> + for s in list_for_each_entry('struct kmem_cache',
> + memcg.kmem_caches.address_of_(),
> + 'memcg_params.kmem_caches_node'):

Are you sure this is the right version? In the previous version
you had the if-else loop that handled shared_slab_pages and old
scheme separately.

Regards,
Bharata.

2020-02-12 20:45:42

by Roman Gushchin

[permalink] [raw]

Subject: Re: [PATCH v2 27/28] tools/cgroup: make slabinfo.py compatible with new slab controller

On Wed, Feb 12, 2020 at 10:51:24AM +0530, Bharata B Rao wrote:
> On Fri, Jan 31, 2020 at 10:24:58PM +0000, Roman Gushchin wrote:
> > On Thu, Jan 30, 2020 at 07:47:29AM +0530, Bharata B Rao wrote:
> > > On Mon, Jan 27, 2020 at 09:34:52AM -0800, Roman Gushchin wrote:
> >
> > Btw, I've checked that the change like you've done above fixes the problem.
> > The script works for me both on current upstream and new_slab.2 branch.
> >
> > Are you sure that in your case there is some kernel memory charged to that
> > cgroup? Please note, that in the current implementation kmem_caches are created
> > on demand, so the accounting is effectively enabled with some delay.
>
> I do see kmem getting charged.
>
> # cat /sys/fs/cgroup/memory/1/memory.kmem.usage_in_bytes /sys/fs/cgroup/memory/1/memory.usage_in_bytes
> 182910976
> 4515627008

Great.

>
> > Below is an updated version of the patch to use:
>
> I see the below failure with this updated version:

Are you sure that drgn is picking right symbols?
I had a similar transient issue during my work, when drgn was actually
using symbols from a different kernel.

>
> # ./tools/cgroup/slabinfo-new.py /sys/fs/cgroup/memory/1
> # name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab> : tunables <limit> <batchcount> <sharedfactor> : slabdata <active_slabs> <num_slabs> <sharedavail>
> Traceback (most recent call last):
> File "/usr/local/bin/drgn", line 11, in <module>
> sys.exit(main())
> File "/usr/local/lib/python3.6/dist-packages/drgn/internal/cli.py", line 127, in main
> runpy.run_path(args.script[0], init_globals=init_globals, run_name="__main__")
> File "/usr/lib/python3.6/runpy.py", line 263, in run_path
> pkg_name=pkg_name, script_name=fname)
> File "/usr/lib/python3.6/runpy.py", line 96, in _run_module_code
> mod_name, mod_spec, pkg_name, script_name)
> File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
> exec(code, run_globals)
> File "./tools/cgroup/slabinfo-new.py", line 158, in <module>
> main()
> File "./tools/cgroup/slabinfo-new.py", line 153, in main
> memcg.kmem_caches.address_of_(),
> AttributeError: 'struct mem_cgroup' has no member 'kmem_caches'
>
> > +
> > +def main():
> > + parser = argparse.ArgumentParser(description=DES,C
> > + 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>')
> > +
> > + for s in list_for_each_entry('struct kmem_cache',
> > + memcg.kmem_caches.address_of_(),
> > + 'memcg_params.kmem_caches_node'):
>
> Are you sure this is the right version? In the previous version
> you had the if-else loop that handled shared_slab_pages and old
> scheme separately.

Which one you're refering to?

As in my tree there are two patches:
fa490da39afb tools/cgroup: add slabinfo.py tool
e3bee81aab44 tools/cgroup: make slabinfo.py compatible with new slab controller

The second one adds the if clause you're probably referring to.

Thanks!

Roman