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From: David Ahern <dsahern@kernel.org>
To: Xin Long <lucien.xin@gmail.com>,
	Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>,
	"David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	netdev@vger.kernel.org, eric.dumazet@gmail.com,
	Willem de Bruijn <willemb@google.com>,
	Coco Li <lixiaoyan@google.com>
Subject: Re: [PATCH net] tcp: fix skb_copy_ubufs() vs BIG TCP
Date: Thu, 27 Apr 2023 20:13:37 -0600	[thread overview]
Message-ID: <3cfdd719-900b-88cf-3fe4-fb277e68325f@kernel.org> (raw)
In-Reply-To: <CADvbK_eX0t9KGuhdERweue3BkefVtzZx-ZQBVhfe8jb1aO6eZw@mail.gmail.com>

On 4/27/23 6:40 PM, Xin Long wrote:
> 
> I just ran David's test scripts in a metal machine:
> 
> There seem memleak with this patch, and the performance is impaired too:
> 
> # free -h
>               total        used        free      shared  buff/cache  
> available
> Mem:           31Gi       999Mi        30Gi        12Mi       303Mi    
>    30Gi


I can confirm the memleak; thanks for noticing that. It is really easy
to reproduce on a real nic by just running tcpdump with large tso packets.



> 
> I could also see some call trace:
> 
> [  271.416989] warn_alloc: 640 callbacks suppressed
> [  271.417006] lt-iperf3: page allocation failure: order:1,
> mode:0x820(GFP_ATOMIC), nodemask=(null),cpuset=/,mems_allowed=0-1
> [  271.432684] CPU: 1 PID: 2218 Comm: lt-iperf3 Tainted: G S            
>     6.3.0.net0 #10
> [  271.440783] Hardware name: Supermicro
> X9DRH-7TF/7F/iTF/iF/X9DRH-7TF/7F/iTF/iF, BIOS 3.2  06/04/2015
> [  271.449831] Call Trace:
> [  271.452276]  <IRQ>
> [  271.454286]  dump_stack_lvl+0x36/0x50
> [  271.457953]  warn_alloc+0x11b/0x190
> [  271.461445]  __alloc_pages_slowpath.constprop.119+0xcb9/0xd40
> [  271.467192]  __alloc_pages+0x32d/0x340
> [  271.470944]  skb_copy_ubufs+0x11b/0x630

I did not trigger this ... perhaps due to memory pressure from the leak?

performance wise, veth hits the skb_copy_ubufs when the packet crosses
the namespace, so ZC performance (with and without hugepages ) lags
non-ZC for the same host use case.

  parent reply	other threads:[~2023-04-28  2:13 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-27 19:24 [PATCH net] tcp: fix skb_copy_ubufs() vs BIG TCP Eric Dumazet
2023-04-27 21:08 ` David Ahern
2023-04-27 21:21   ` Willem de Bruijn
     [not found]     ` <CADvbK_eX0t9KGuhdERweue3BkefVtzZx-ZQBVhfe8jb1aO6eZw@mail.gmail.com>
2023-04-28  2:13       ` David Ahern [this message]
2023-04-28  4:19       ` Eric Dumazet

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