Date: Sun, 06 Jan 2008 23:10:40 -0800 (PST)
Message-Id: <20080106.231040.222338659.davem@davemloft.net>
To: ebiederm@xmission.com
Cc: bcrl@kvack.org, linux-kernel@vger.kernel.org,
       torvalds@linux-foundation.org
Subject: Re: regression: sysctl_check changes in 2.6.24 are O(n) resulting
 in slow creation of 10000 network interfaces
From: David Miller <davem@davemloft.net>
In-Reply-To: <m1ir26ktqi.fsf@ebiederm.dsl.xmission.com>
References: <20080106220307.GU28570@kvack.org>
	<m1ir26ktqi.fsf@ebiederm.dsl.xmission.com>
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From: ebiederm@xmission.com (Eric W. Biederman)
Date: Sun, 06 Jan 2008 23:57:57 -0700

> Why do we need 10000 interfaces?  Why isn't network device creation a
> slow path?

Because people create virtual devices like mad.

> So is this a bug report telling me that there are users with
> 10k or 100k interfaces that care.  So we need to fix sysctl.

Unquestionably, we do, it's a major regression.

People create thousands of VLAN devices, as one of many examples, all
the time.

That's why we even bother hashing network devices in the network code.
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