Subject: Re: 100 network limit

From: Ben Greear <[email-masked]>
Date: Thu, 28 Aug 2003 14:46:39 -0700

Andi Kleen wrote:
> On Fri, 29 Aug 2003 04:00:19 +1000
> Anton Blanchard <[email-masked]> wrote:
> 
> 
> 
>>Anyway as a short term fix Jamal suggested making a sysctl for this
>>maximum. If fixing this all properly is out of the question for 2.6,
>>would the sysctl approach be satisfactory? The other option is to just
>>bump the limit and recognise that the user is on his own if performance
>>sucks.
> 
> 
> You could just add a bitmap with a reasonable upper limit (1024?) and use 
> find_first_zero_bit()  I doubt doing that would be very intrusive.
> 
> -Andi

Since you can rename devices, that might not work.  A long time ago I
hashed the devices, both by name and by index...that gives good lookup performance, at least.  As for
create-time issues, that is definately slow path, and even searching linearly
4 or 8k devices is not a big deal (in my opinion).  So, why not make the hard-coded
100 limit be more like 8196 or something really large?  (It could still be adjustable
if needed.)

Ben

-- 
Ben Greear <[email-masked]>
Candela Technologies Inc  http://www.candelatech.com