netdev - Re: [PATCH v1 net-next 11/13] net-memcg: Add memory.socket

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

Message-ID: <pvygtpy4b7napeudlk5dtbacgvqf6j4lrr5nhye6obrwv2ss2o@ubxpyqwf56pz>
Date: Thu, 31 Jul 2025 15:39:06 +0200
From: Michal Koutný <mkoutny@...e.com>
To: Kuniyuki Iwashima <kuniyu@...gle.com>
Cc: "David S. Miller" <davem@...emloft.net>, 
	Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, 
	Neal Cardwell <ncardwell@...gle.com>, Paolo Abeni <pabeni@...hat.com>, 
	Willem de Bruijn <willemb@...gle.com>, Matthieu Baerts <matttbe@...nel.org>, 
	Mat Martineau <martineau@...nel.org>, Johannes Weiner <hannes@...xchg.org>, 
	Michal Hocko <mhocko@...nel.org>, Roman Gushchin <roman.gushchin@...ux.dev>, 
	Shakeel Butt <shakeel.butt@...ux.dev>, Andrew Morton <akpm@...ux-foundation.org>, 
	Simon Horman <horms@...nel.org>, Geliang Tang <geliang@...nel.org>, 
	Muchun Song <muchun.song@...ux.dev>, Kuniyuki Iwashima <kuni1840@...il.com>, netdev@...r.kernel.org, 
	mptcp@...ts.linux.dev, cgroups@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH v1 net-next 11/13] net-memcg: Add memory.socket_isolated
 knob.

Hello  Kuniyuki.

On Mon, Jul 21, 2025 at 08:35:30PM +0000, Kuniyuki Iwashima <kuniyu@...gle.com> wrote:
> --- a/Documentation/admin-guide/cgroup-v2.rst
> +++ b/Documentation/admin-guide/cgroup-v2.rst
> @@ -1878,6 +1878,22 @@ The following nested keys are defined.
>  	Shows pressure stall information for memory. See
>  	:ref:`Documentation/accounting/psi.rst <psi>` for details.
>  
> +  memory.socket_isolated
> +	A read-write single value file which exists on non-root cgroups.
> +	The default value is "0".

Such attributes don't fit well into hierarchy.
What are expectations in non-root non-leaf cgroups?

Also the global limit is not so much different from a memcg limit
configured on ancestors. This provision thus looks like handling only
one particular case.

> +
> +	Some networking protocols (e.g., TCP, UDP) implement their own memory
> +	accounting for socket buffers.
> +
> +	This memory is also charged to a non-root cgroup as sock in memory.stat.
> +
> +	Since per-protocol limits such as /proc/sys/net/ipv4/tcp_mem and
> +	/proc/sys/net/ipv4/udp_mem are global, memory allocation for socket
> +	buffers may fail even when the cgroup has available memory.
> +
> +	Sockets created with socket_isolated set to 1 are no longer subject
> +	to these global protocol limits.

What happens when it's changed during lifetime of cgroup?

Thanks,
Michal

Download attachment "signature.asc" of type "application/pgp-signature" (229 bytes)