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From: David Miller <davem@davemloft.net>
To: davidel@xmailserver.org
Cc: eric.dumazet@gmail.com, oleg@redhat.com, jolsa@redhat.com,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	fbl@redhat.com, nhorman@redhat.com, htejun@gmail.com
Subject: Re: [PATCH] net: fix race in the receive/select
Date: Thu, 25 Jun 2009 19:11:41 -0700 (PDT)	[thread overview]
Message-ID: <20090625.191141.261414015.davem@davemloft.net> (raw)
In-Reply-To: <alpine.DEB.1.10.0906251858520.9517@makko.or.mcafeemobile.com>

From: Davide Libenzi <davidel@xmailserver.org>
Date: Thu, 25 Jun 2009 19:04:04 -0700 (PDT)

> On Fri, 26 Jun 2009, Eric Dumazet wrote:
> 
>> Adding a plain smp_mb() in tcp_poll() for example would slowdown select()/poll() with NULL
>> timeout.
> 
> Do you think of it as good design adding an MB on a subsystem, because of 
> the special locking logic of another one?
> The (eventual) slowdown, IMO can be argued sideways, by saying that 
> non-socket users will pay the price for their polls.

Perhaps every performance argument is moot since spin_unlock() used to
have the barrier :-)

  reply	other threads:[~2009-06-26  2:11 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-25 12:25 [PATCH] net: fix race in the receive/select Jiri Olsa
2009-06-25 12:24 ` Oleg Nesterov
2009-06-26  1:31   ` Davide Libenzi
2009-06-26  1:59     ` Eric Dumazet
2009-06-26  2:04       ` Davide Libenzi
2009-06-26  2:11         ` David Miller [this message]
2009-06-26  2:19         ` Eric Dumazet
2009-06-26  3:14           ` Davide Libenzi
2009-06-26  5:42             ` Jarek Poplawski
2009-06-26  8:10               ` Jarek Poplawski
2009-06-26 13:57             ` Oleg Nesterov
2009-06-26 17:32               ` Davide Libenzi
2009-06-26 14:50                 ` Oleg Nesterov
2009-06-26 18:12                   ` Davide Libenzi
2009-06-26 18:17                     ` David Miller
2009-06-26 19:35                       ` Eric Dumazet
2009-06-29  9:34                         ` Jiri Olsa
2009-06-28 11:10                   ` Jarek Poplawski
2009-06-28 11:22                     ` Jarek Poplawski
2009-06-28 18:04                       ` Oleg Nesterov
2009-06-28 21:48                         ` Jarek Poplawski
2009-06-29  9:27                           ` Jiri Olsa
2009-06-26 13:46           ` Oleg Nesterov
2009-06-25 23:18 ` Eric Dumazet
2009-06-26  1:50 ` Tejun Heo
2009-06-29  9:12 ` Andi Kleen
2009-06-29  9:24   ` Jiri Olsa
2009-06-29 16:59   ` Zan Lynx
2009-06-29 17:29     ` Andi Kleen
2009-07-01  3:39   ` Herbert Xu
2009-07-01  6:27     ` Andi Kleen
2009-07-01  7:03       ` Herbert Xu
2009-07-01  7:22         ` Andi Kleen
2009-07-01  8:31           ` Herbert Xu
2009-07-01  8:44             ` Jiri Olsa
2009-07-01 10:58               ` Herbert Xu
2009-07-01 13:07                 ` Herbert Xu

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