Subject: Re: small RPS cache for fragments?

From: Andi Kleen <[email-masked]>
Date: Tue, 17 May 2011 15:03:56 -0700

Eric Dumazet <[email-masked]> writes:

>> They're not rwlocks, but especially if the locking was more finegrained
>> that's likely not needed anymore.
>
> Well, there is the rehashing stuff, and this locks the whole table.
>
> Not easy to switch to rcu or something like that.

No need to switch to RCU, just a more finegrained bucket lock.

If you move a chain between queues you just lock both for the move.
It sounds easy enough. I should probably just code it up.

>
> Anyway I hardly use frags here at work, so never considered it was a
> field to spend time ;)

Yes that's the problem. On the other hand most scalability problems hurt
sooner or later, so sometimes it's good to fix them in advance.

-Andi

-- 
[email-masked] -- Speaking for myself only