From: Eric Dumazet <eric.dumazet@gmail.com>
To: Qian Cai <cai@lca.pw>, Eric Dumazet <eric.dumazet@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Michal Hocko <mhocko@kernel.org>,
davem@davemloft.net, netdev@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Petr Mladek <pmladek@suse.com>,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH] net/skbuff: silence warnings under memory pressure
Date: Thu, 5 Sep 2019 17:14:15 +0200 [thread overview]
Message-ID: <5405caf6-805b-d459-c447-15a23d0d71dd@gmail.com> (raw)
In-Reply-To: <1567692555.5576.91.camel@lca.pw>
On 9/5/19 4:09 PM, Qian Cai wrote:
> Instead of repeatedly make generalize statements, could you enlighten me with
> some concrete examples that have the similar properties which would trigger a
> livelock,
>
> - guaranteed GFP_ATOMIC allocations when processing softirq batches.
> - the allocation has a fallback mechanism that is unnecessary to warn a failure.
>
> I thought "skb" is a special-case here as every packet sent or received is
> handled using this data structure.
>
Just 'git grep GFP_ATOMIC -- net' and carefully study all the places.
You will discover many allocations done for incoming packets.
All of them can fail and trigger a trace.
Please fix the problem for good, do not pretend addressing the skb allocations
will solve it.
The skb allocation can succeed, then the following allocation might fail.
skb are one of the many objects that networking need to allocate dynamically.
next prev parent reply other threads:[~2019-09-05 15:14 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-30 14:57 Qian Cai
2019-08-30 15:11 ` Eric Dumazet
2019-08-30 15:25 ` Qian Cai
2019-08-30 16:15 ` Eric Dumazet
2019-08-30 18:06 ` Qian Cai
2019-09-03 13:22 ` Michal Hocko
2019-09-03 15:42 ` Qian Cai
2019-09-03 18:53 ` Michal Hocko
2019-09-03 21:42 ` Qian Cai
2019-09-04 6:15 ` Michal Hocko
2019-09-04 6:41 ` Sergey Senozhatsky
2019-09-04 6:54 ` Michal Hocko
2019-09-04 7:19 ` Sergey Senozhatsky
2019-09-04 7:43 ` Sergey Senozhatsky
2019-09-04 12:14 ` Qian Cai
2019-09-04 14:48 ` Sergey Senozhatsky
2019-09-04 15:07 ` Qian Cai
2019-09-04 20:42 ` Qian Cai
2019-09-05 8:32 ` Eric Dumazet
2019-09-05 14:09 ` Qian Cai
2019-09-05 15:06 ` Eric Dumazet
2019-09-05 15:14 ` Eric Dumazet [this message]
2019-09-05 11:32 ` Sergey Senozhatsky
2019-09-05 16:03 ` Qian Cai
2019-09-05 17:14 ` Steven Rostedt
2019-09-06 2:50 ` Sergey Senozhatsky
2019-09-06 4:32 ` Sergey Senozhatsky
2019-09-06 21:17 ` Qian Cai
2019-09-05 17:23 ` Steven Rostedt
2019-09-06 3:39 ` Sergey Senozhatsky
2019-09-06 15:32 ` Petr Mladek
2019-09-09 1:10 ` Sergey Senozhatsky
2019-09-06 14:55 ` Petr Mladek
2019-09-06 19:51 ` Sergey Senozhatsky
2019-11-14 17:12 ` Qian Cai
2019-11-18 15:27 ` Petr Mladek
2019-11-19 0:41 ` Sergey Senozhatsky
2019-11-19 9:41 ` Petr Mladek
2019-11-19 15:58 ` Qian Cai
2019-11-20 1:30 ` Sergey Senozhatsky
2019-11-20 16:13 ` Petr Mladek
2019-11-21 1:05 ` Sergey Senozhatsky
2019-11-21 9:15 ` Petr Mladek
2019-09-04 7:00 ` Sergey Senozhatsky
2019-09-04 8:25 ` Michal Hocko
2019-09-04 11:59 ` Qian Cai
2019-09-04 12:07 ` Michal Hocko
2019-09-04 12:28 ` Qian Cai
2019-09-04 6:15 ` Michal Hocko
2019-09-02 14:24 ` Vlastimil Babka
2019-09-03 10:23 ` Qian Cai
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