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From: Eric Dumazet <dada1@cosmosbay•com>
To: Evgeniy Polyakov <zbr@ioremap•net>
Cc: Stephen Hemminger <shemminger@vyatta•com>,
	Herbert Xu <herbert@gondor•apana.org.au>,
	berrange@redhat•com, et-mgmt-tools@redhat•com,
	davem@davemloft•net, netdev@vger•kernel.org
Subject: Re: virt-manager broken by bind(0) in net-next.
Date: Sat, 31 Jan 2009 10:17:44 +0100	[thread overview]
Message-ID: <49841738.7050605@cosmosbay.com> (raw)
In-Reply-To: <20090131083724.GB26897@ioremap.net>

Evgeniy Polyakov a écrit :
> On Fri, Jan 30, 2009 at 06:52:24PM -0800, Stephen Hemminger (shemminger@vyatta•com) wrote:
>> My working hypothesis is:
>>   1. Something about Evgeniy's patch makes IPV6 (actually IPV4 in IPV6) be
>>      preferred over plain IPV4.
>>   2. Vino server (VNC) doesn't think ::ffff::127.0.0.1 is really the localhost
>>   3. protocol gets screwed up after that.
>>
>> It is probably reproducible with other services that support IPV6.
> 
> getaddrinfo() returns list of addresses and IPv6 was the first one iirc.
> Previously it bailed out, but with my change it will try again without
> reason for doing this. With the patch I sent based on Eric's observation
> things should be fine.
> 

Problem is your patch is wrong Evgeniy, please think about it litle bit more
and resubmit it. 

Take the time to run this $0.02 program, before and after your upcoming fix :


$ cat size.c
#include <net/inet_hashtables.h>
extern int printf(const char *, ...);
int main(int argc, char *argv[])
{
        printf("offsetof(struct inet_hashinfo, bsockets)=0x%x\n",
                offsetof(struct inet_hashinfo, bsockets));
        return 0;
}
$ make size.o ; gcc -o size size.o ; ./size
  CHK     include/linux/version.h
  CHK     include/linux/utsrelease.h
  SYMLINK include/asm -> include/asm-x86
  CALL    scripts/checksyscalls.sh
  CC      size.o
offsetof(struct inet_hashinfo, bsockets)=0x18


offset of bsockets being 0x18 or 0x20 is same result : bad because in
same cache line than ehash, ehash_locks, ehash_size, ehash_locks_mask,
bhash, bhash_size, unless your cpu is a Pentium.

Also, I suggest you change bsockets to something more appropriate, eg a
percpu counter.

Thank you.
Eric


  reply	other threads:[~2009-01-31  9:18 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20090128212114.38be3e8c@extreme>
     [not found] ` <20090129103544.GC22110@redhat.com>
2009-01-30  5:35   ` virt-manager broken by bind(0) in net-next Stephen Hemminger
2009-01-30  8:16     ` Evgeniy Polyakov
     [not found]       ` <20090130081600.GA2717-i6C2adt8DTjR7s880joybQ@public.gmane.org>
2009-01-30 10:27         ` Daniel P. Berrange
2009-01-30 11:21           ` Evgeniy Polyakov
2009-01-30 12:53             ` Herbert Xu
     [not found]               ` <20090130125337.GA7155-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org>
2009-01-30 17:57                 ` Stephen Hemminger
2009-01-30 18:41                   ` Eric Dumazet
2009-01-30 21:50                     ` Evgeniy Polyakov
2009-01-30 22:30                       ` Eric Dumazet
2009-01-30 22:51                         ` Evgeniy Polyakov
     [not found]                           ` <20090130225113.GA13977-i6C2adt8DTjR7s880joybQ@public.gmane.org>
2009-01-31  0:36                             ` Stephen Hemminger
2009-01-31  8:35                               ` Evgeniy Polyakov
2009-01-31  2:52                             ` Stephen Hemminger
2009-01-31  8:37                               ` Evgeniy Polyakov
2009-01-31  9:17                                 ` Eric Dumazet [this message]
2009-01-31  9:31                                   ` Evgeniy Polyakov
2009-01-31  9:49                                     ` Eric Dumazet
2009-01-31  9:56                                       ` Evgeniy Polyakov
2009-01-31 10:17                                         ` Eric Dumazet
2009-02-01 12:42                                           ` Evgeniy Polyakov
2009-02-01 16:12                                             ` Eric Dumazet
2009-02-01 17:40                                               ` Evgeniy Polyakov
2009-02-01 20:31                                                 ` David Miller
     [not found]                       ` <20090130215008.GB12210-i6C2adt8DTjR7s880joybQ@public.gmane.org>
2009-02-01  5:58                         ` Stephen Hemminger
2009-02-01  9:07                           ` David Miller
2009-02-01 12:44                           ` Evgeniy Polyakov
     [not found]                     ` <498349F7.4050300-fPLkHRcR87vqlBn2x/YWAg@public.gmane.org>
2009-02-01  5:29                       ` Stephen Hemminger
2009-01-30  6:50   ` Stephen Hemminger

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