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From: Roman Gushchin <guro@fb.com>
To: Shakeel Butt <shakeelb@google.com>
Cc: Eric Dumazet <edumazet@google.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>,
	Greg Thelen <gthelen@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"David S . Miller" <davem@davemloft.net>,
	Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	<netdev@vger.kernel.org>, <linux-mm@kvack.org>,
	<cgroups@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 2/2] net: memcg: late association of sock to memcg
Date: Tue, 10 Mar 2020 15:38:48 -0700	[thread overview]
Message-ID: <20200310223848.GC96999@carbon.dhcp.thefacebook.com> (raw)
In-Reply-To: <20200310051606.33121-2-shakeelb@google.com>

On Mon, Mar 09, 2020 at 10:16:06PM -0700, Shakeel Butt wrote:
> If a TCP socket is allocated in IRQ context or cloned from unassociated
> (i.e. not associated to a memcg) in IRQ context then it will remain
> unassociated for its whole life. Almost half of the TCPs created on the
> system are created in IRQ context, so, memory used by such sockets will
> not be accounted by the memcg.
> 
> This issue is more widespread in cgroup v1 where network memory
> accounting is opt-in but it can happen in cgroup v2 if the source socket
> for the cloning was created in root memcg.
> 
> To fix the issue, just do the association of the sockets at the accept()
> time in the process context and then force charge the memory buffer
> already used and reserved by the socket.
> 
> Signed-off-by: Shakeel Butt <shakeelb@google.com>

Reviewed-by: Roman Gushchin <guro@fb.com>

Thank you!


  parent reply	other threads:[~2020-03-10 22:39 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200310051606.33121-1-shakeelb@google.com>
2020-03-10  5:16 ` [PATCH v4 2/2] net: memcg: late association of sock to memcg Shakeel Butt
2020-03-10 15:53   ` Eric Dumazet
2020-03-10 22:34   ` David Miller
2020-03-10 22:38   ` Roman Gushchin [this message]
2020-03-12 14:03   ` Qian Cai
2020-03-12 14:05     ` Shakeel Butt
2020-03-10 22:34 ` [PATCH v4 1/2] cgroup: memcg: net: do not associate sock with unrelated cgroup David Miller

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