linux-kernel - [PATCH v3 0/4] memcg: decouple memcg and objcg stocks

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250506225533.2580386-1-shakeel.butt@linux.dev>
Date: Tue,  6 May 2025 15:55:29 -0700
From: Shakeel Butt <shakeel.butt@...ux.dev>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Johannes Weiner <hannes@...xchg.org>,
	Michal Hocko <mhocko@...nel.org>,
	Roman Gushchin <roman.gushchin@...ux.dev>,
	Muchun Song <muchun.song@...ux.dev>,
	Alexei Starovoitov <ast@...nel.org>,
	Vlastimil Babka <vbabka@...e.cz>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	Jakub Kicinski <kuba@...nel.org>,
	Eric Dumazet <edumazet@...gle.com>,
	linux-mm@...ck.org,
	cgroups@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	bpf@...r.kernel.org,
	netdev@...r.kernel.org,
	Meta kernel team <kernel-team@...a.com>
Subject: [PATCH v3 0/4] memcg: decouple memcg and objcg stocks

The per-cpu memcg charge cache and objcg charge cache are coupled in a
single struct memcg_stock_pcp and a single local lock is used to protect
both of the caches. This makes memcg charging and objcg charging nmi
safe challenging. Decoupling memcg and objcg stocks would allow us to
make them nmi safe and even work without disabling irqs independently.
This series completely decouples memcg and objcg stocks.

To evaluate the impact of this series with and without PREEMPT_RT
config, we ran varying number of netperf clients in different cgroups on
a 72 CPU machine.

 $ netserver -6
 $ netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K

PREEMPT_RT config:
------------------
number of clients | Without series | With series
  6               | 38559.1 Mbps   | 38652.6 Mbps
  12              | 37388.8 Mbps   | 37560.1 Mbps
  18              | 30707.5 Mbps   | 31378.3 Mbps
  24              | 25908.4 Mbps   | 26423.9 Mbps
  30              | 22347.7 Mbps   | 22326.5 Mbps
  36              | 20235.1 Mbps   | 20165.0 Mbps

!PREEMPT_RT config:
-------------------
number of clients | Without series | With series
  6               | 50235.7 Mbps   | 51415.4 Mbps
  12              | 49336.5 Mbps   | 49901.4 Mbps
  18              | 46306.8 Mbps   | 46482.7 Mbps
  24              | 38145.7 Mbps   | 38729.4 Mbps
  30              | 30347.6 Mbps   | 31698.2 Mbps
  36              | 26976.6 Mbps   | 27364.4 Mbps

No performance regression was observed.

Changes since v2:
- Ran and included network intensive benchmarking results
- Brought back the simplify patch dropped in v2 after perf experiment.

Changes since v1:
- Drop first patch as requested by Alexei.
- Remove preempt_disable() usage as suggested by Vlastimil.

Shakeel Butt (4):
  memcg: simplify consume_stock
  memcg: separate local_trylock for memcg and obj
  memcg: completely decouple memcg and obj stocks
  memcg: no irq disable for memcg stock lock

 mm/memcontrol.c | 175 ++++++++++++++++++++++++++++--------------------
 1 file changed, 102 insertions(+), 73 deletions(-)

-- 
2.47.1