netdev - Re: [PATCH] netfilter: netns nf_conntrack: per-netns net.netfilter.nf_conntrack

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Message-Id: <20250408082708.56208-1-xiafei_xupt@163.com>
Date: Tue,  8 Apr 2025 16:27:08 +0800
From: lvxiafei <xiafei_xupt@....com>
To: ej@...i.de
Cc: coreteam@...filter.org,
	davem@...emloft.net,
	edumazet@...gle.com,
	fw@...len.de,
	horms@...nel.org,
	kadlec@...filter.org,
	kuba@...nel.org,
	linux-kernel@...r.kernel.org,
	lvxiafei@...setime.com,
	netdev@...r.kernel.org,
	netfilter-devel@...r.kernel.org,
	pabeni@...hat.com,
	pablo@...filter.org,
	xiafei_xupt@....com
Subject: Re: [PATCH] netfilter: netns nf_conntrack: per-netns net.netfilter.nf_conntrack_max sysctl

On Mon, 7 Apr 2025 12:56:33
Jan Engelhardt <ej@...i.de> wrote:
> By inheriting an implicit limit from the parent namespace somehow.
> For example, even if you set the kernel.pid_max sysctl in the initial
> namespace to something like 9999, subordinate namespace have
> kernel.pid_max=4million again, but nevertheless are unable to use
> more than 9999 PIDs. Or so documentation the documentation
> from commit d385c8bceb14665e935419334aa3d3fac2f10456 tells me
> (I did not try to create so many processes by myself).
>
> A similar logic would have to be applied for netfilter sysctls
> if they are made modifiable in subordinate namespaces.

The patch is to use nf_conntrack_max to more flexibly limit the
ct_count in different netns, which may be greater than the parent
namespace, belonging to the global (ancestral) limit, and there
is no implicit limit inherited from the parent namespace