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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Denys Fedoryshchenko <denys@visp.net.lb>
Cc: netdev@vger.kernel.org
Subject: Re: 2.6.39-rc7-git11, x86/32, failed on ppp2897'th interface, PERCPU:  allocation failed
Date: Thu, 19 May 2011 08:55:13 +0200	[thread overview]
Message-ID: <1305788113.3019.19.camel@edumazet-laptop> (raw)
In-Reply-To: <1305787158.3019.12.camel@edumazet-laptop>

Le jeudi 19 mai 2011 à 08:39 +0200, Eric Dumazet a écrit :

> Its a known problem : When ipv6 is enabled, we allocate percpu memory to
> hold per device snmp counters.
> 
> make sure kernel idea of max possible cpus matches real number of cpus.
> 
> And yes, switching to 64bit kernel helps a lot.
> 
> 

Looking at snmp6_alloc_dev(), we allocate three mib per device :

ipstats_mib  (30 * sizeof(u64) * number_of_possible_cpus)
icmpv6_mib    (4 * sizeof(long) * number_of_possible_cpus)
icmpv6msg_mib  (26 * sizeof(long))

For sure icmp ones dont need percpu counter. Plain atomic_long_t
(shared) would be enough, since ICMP messages are rare enough.




  parent reply	other threads:[~2011-05-19  6:55 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-19  6:35 2.6.39-rc7-git11, x86/32, failed on ppp2897'th interface, PERCPU: allocation failed Denys Fedoryshchenko
2011-05-19  6:39 ` Eric Dumazet
2011-05-19  6:47   ` Denys Fedoryshchenko
2011-05-19  6:55   ` Eric Dumazet [this message]
2011-05-19  7:28     ` Denys Fedoryshchenko
2011-05-19  7:44       ` Eric Dumazet
2011-05-19 11:14     ` [PATCH net-next-2.6] ipv6: reduce per device ICMP mib sizes Eric Dumazet
2011-05-19 11:26       ` Denys Fedoryshchenko
2011-05-19 20:19       ` David Miller
2011-05-19  7:51 ` 2.6.39-rc7-git11, x86/32, failed on ppp2897'th interface, PERCPU: allocation failed David Miller

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