netdev - Re: [RFC] net/core/dst.c : Should'nt dst_run_gc() be more scalable and friendly ?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 17 Aug 2007 16:15:22 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Eric Dumazet <dada1@...mosbay.com>
Cc:	netdev@...r.kernel.org
Subject: Re: [RFC] net/core/dst.c : Should'nt dst_run_gc() be more scalable and friendly ?

On Fri, Aug 17, 2007 at 10:10:30AM +0200, Eric Dumazet wrote:
>
> Will a workqueue react the same in case of a DDOS situation, 
> where softirq could use all CPU cycles to handle incoming
> packets and feed the GC list, and GC would never
> have a chance to scan and free some items ?

Well when that happens the softirqs will be deferred to
ksoftirqd which should share the CPU fairly with the
workqueue.

> About chunk processing, I did it on purpose, to not throw away
> all CPU cache. Goal is to process entries, but not all of them
> in a row, especially if we find many yet referenced entries
> (and thus not candidates to freeing)

I agree that chunks are desirable for a timer since you'd
be hogging the CPU otherwise.  However, if you went to a
workqueue then it's less of a concern and would simplify
things.  In particular, you won't have to pick a good
chunk size :)

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html