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From: Denys Fedoryshchenko <denys@visp.net.lb>
To: Eric Dumazet <eric.dumazet@gmail.com>
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 10:28:26 +0300	[thread overview]
Message-ID: <10f61af229a48d77d06d154b4647cdde@visp.net.lb> (raw)
In-Reply-To: <1305788113.3019.19.camel@edumazet-laptop>

 On Thu, 19 May 2011 08:55:13 +0200, Eric Dumazet wrote:
> 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))
 1920 +
 256 +
 208 = 2386 * 3000ppp's = 7152000, i think it is not that much at any 
 case, if i am not wrong.

 But at any case i will try 64bit.

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



  reply	other threads:[~2011-05-19  7:28 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
2011-05-19  7:28     ` Denys Fedoryshchenko [this message]
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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