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From: Octavian Purdila <opurdila-+zzKsuq53OdBDgjK7y7TUQ@public•gmane.org>
To: David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public•gmane.org>
Cc: amwang-H+wXaHxf7aLQT0dZR+AlfA@public•gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
	eric.dumazet-Re5JQEeQqe8AvxtiuMwx3w@public•gmane.org,
	linux-rdma-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
	netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
	nhorman-2XuSBdqkA4R54TAoqtyWWQ@public•gmane.org,
	linux-sctp-u79uwXL29TY76Z2rM5mHXA@public•gmane.org
Subject: Re: [RFC Patch] net: reserve ports for applications using fixed port numbers
Date: Thu, 4 Feb 2010 20:15:51 +0200	[thread overview]
Message-ID: <201002042015.51092.opurdila@ixiacom.com> (raw)
In-Reply-To: <20100204.094110.64247447.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>

On Thursday 04 February 2010 19:41:10 you wrote:

> From: Octavian Purdila <opurdila-+zzKsuq53OdBDgjK7y7TUQ@public•gmane.org>
> Date: Thu, 4 Feb 2010 14:44:01 +0200
> 
> > My concern is that we can have multiple applications that require a
> > fixed port and if those ports are significantly apart we will
> > decrease the port range available for connect. And that will hurt
> > the rate of which new connections can be opened.
> 
> I'm already uneasy about adding the simple check every time
> we loop around in the bind port allocator.
> 
> Adding an LSM hook to this spot?  I absolutely refuse to allow
> that, it will completely kill bind performance.
> 

I think Tetsuo was proposing the LSM hook, so I'll leave him the daunting task 
of convincing you of the benefit of that :) - I have no opinion on this due to 
massive lack of knowledge.

I was just proposing to use a discrete set of ports instead of a range. The 
check in the current patch:

int inet_is_reserved_local_port(int port)
{
       int min, max;

       inet_get_local_reserved_ports(&min, &max);
       if (min && max)
               return (port >= min && port <= max);
       return 0;
}

would become:

int inet_is_reserved_local_port(int port)
{
	if (test_bit(port, reserved_ports))
		return 1;
	return 0;
}

In theory it might be slower because of the reserved_ports bitmap will have a 
larger memory footprint than just a min/max, especially with random port 
allocation. But is this an issue in practice?
--
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  parent reply	other threads:[~2010-02-04 18:15 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-03  4:30 [RFC Patch] net: reserve ports for applications using fixed port numbers Amerigo Wang
     [not found] ` <20100203043332.3817.27932.sendpatchset-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org>
2010-02-03  4:39   ` Eric Dumazet
2010-02-03  5:15     ` Cong Wang
2010-02-03 11:12   ` Octavian Purdila
     [not found]     ` <201002031312.48531.opurdila-+zzKsuq53OdBDgjK7y7TUQ@public.gmane.org>
2010-02-04  3:23       ` Cong Wang
     [not found]         ` <4B6A3DBA.1000706-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2010-02-04 12:44           ` Octavian Purdila
     [not found]             ` <201002041444.01897.opurdila-+zzKsuq53OdBDgjK7y7TUQ@public.gmane.org>
2010-02-04 17:41               ` David Miller
     [not found]                 ` <20100204.094110.64247447.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
2010-02-04 18:15                   ` Octavian Purdila [this message]
     [not found]                     ` <201002042015.51092.opurdila-+zzKsuq53OdBDgjK7y7TUQ@public.gmane.org>
2010-02-04 18:21                       ` David Miller
2010-02-04 21:45                       ` Tetsuo Handa
     [not found]                         ` <201002050645.CEC95380.MLOtOVFFHSFOQJ-JPay3/Yim36HaxMnTkn67Xf5DAMn2ifp@public.gmane.org>
2010-02-04 21:56                           ` David Miller
2010-02-05  0:41                             ` Tetsuo Handa
2010-02-05  1:05                               ` Octavian Purdila
2010-02-05  6:01                                 ` Cong Wang
2010-02-05 12:28                                   ` Octavian Purdila
2010-02-05  4:45                     ` Cong Wang
     [not found]                       ` <4B6BA272.4090405-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2010-02-05 12:05                         ` Octavian Purdila
     [not found]                           ` <201002051405.54029.opurdila-+zzKsuq53OdBDgjK7y7TUQ@public.gmane.org>
2010-02-08  3:21                             ` Cong Wang
     [not found]                               ` <4B6F834E.4010801-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2010-02-08 16:51                                 ` Octavian Purdila
2010-02-05  7:11 ` Bart Van Assche
2010-02-05  7:25   ` Cong Wang
2010-02-05  9:08     ` [RFC Patch] net: reserve ports for applications using fixed portnumbers Tetsuo Handa

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