From: Sowmini Varadhan <sowmini.varadhan@oracle.com>
To: Tom Herbert <tom@herbertland.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Linux Kernel Network Developers <netdev@vger.kernel.org>,
Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH net] net: Allow flow dissector to handle non 4-byte aligned headers
Date: Wed, 3 Feb 2016 12:31:25 -0500 [thread overview]
Message-ID: <20160203173125.GA14627@oracle.com> (raw)
In-Reply-To: <CALx6S34MGwp2m=QmfQ36tWnaWbFXvMG63sj7Nz1KgMtegxn-2A@mail.gmail.com>
On (02/03/16 09:07), Tom Herbert wrote:
> > Kernel unaligned access at TPC[9150dc] ipv4_neigh_lookup+0x38/0x170
>
> Sowmini,
>
> This doesn't look like a hard crash to me. Instead of trying to fix
> all the alignment issues for Sparc, can we just take the trap, fix up
> the load, and continue without any further fuss? Performance might
> suffer, but it doesn't seem like the bad alignments are happening in
> critical paths.
>
None of these things is a hard crash, but they are
(a) quite noisy
(b) I'm able to generate alignment falls merely by configuring
tunnels, and it gets worse when I disable RSS and use RFS/RPS
instead. So "critical path" might need some definition.
(c) a perf risk for other platforms as well, even when they dont
complain noisily about it.
--Sowmini
next prev parent reply other threads:[~2016-02-03 17:31 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-31 21:37 [PATCH net] net: Allow flow dissector to handle non 4-byte aligned headers Tom Herbert
2016-01-31 21:47 ` kbuild test robot
2016-01-31 22:06 ` Florian Westphal
2016-02-01 0:24 ` Eric Dumazet
2016-02-01 0:39 ` Florian Fainelli
2016-02-01 15:20 ` Nicolas Dichtel
2016-02-01 16:01 ` Sowmini Varadhan
2016-02-01 0:43 ` Sowmini Varadhan
2016-02-01 12:32 ` Sergei Shtylyov
2016-02-02 0:31 ` Sowmini Varadhan
2016-02-02 0:46 ` Tom Herbert
2016-02-02 3:56 ` Alexander Duyck
2016-02-02 13:41 ` Hannes Frederic Sowa
2016-02-02 18:35 ` Sowmini Varadhan
2016-02-03 17:07 ` Tom Herbert
2016-02-03 17:31 ` Sowmini Varadhan [this message]
2016-02-03 17:51 ` Tom Herbert
2016-02-03 17:59 ` Sowmini Varadhan
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