From: Eric Dumazet <eric.dumazet@gmail.com>
To: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Hannes Frederic Sowa <hannes@stressinduktion.org>,
netdev@vger.kernel.org
Subject: Re: [net-next PATCH 4/4] net: frag LRU list per CPU
Date: Wed, 24 Apr 2013 19:05:46 -0700 [thread overview]
Message-ID: <1366855546.8964.125.camel@edumazet-glaptop> (raw)
In-Reply-To: <1366849557.8964.110.camel@edumazet-glaptop>
On Wed, 2013-04-24 at 17:25 -0700, Eric Dumazet wrote:
> We know that a slow sender has no chance to complete a packet if the
> attacker can create new fragments fast enough : frag_evictor() will keep
> the attacker fragments in memory and throw away good fragments.
>
By the way, the frag_evictor() idea of cleaning 20% or 30% of the frags
simply doesn't scale to thousands of fragments.
It adds huge latencies in softirq context.
If we really want to evict old fragments before expiration timer, then
we can introduce a garbage collector in a work queue, and remove the
need of a timer per fragment.
next prev parent reply other threads:[~2013-04-25 2:05 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-24 15:47 [net-next PATCH 0/4] net: frag patchset for fixing LRU scalability issue Jesper Dangaard Brouer
2013-04-24 15:48 ` [net-next PATCH 1/4] Revert "inet: limit length of fragment queue hash table bucket lists" Jesper Dangaard Brouer
2013-04-25 0:00 ` Eric Dumazet
2013-04-25 13:10 ` Jesper Dangaard Brouer
2013-04-25 13:58 ` David Laight
2013-05-02 7:59 ` Jesper Dangaard Brouer
2013-05-02 15:16 ` Eric Dumazet
2013-05-03 9:15 ` Jesper Dangaard Brouer
2013-04-24 15:48 ` [net-next PATCH 2/4] net: increase frag hash size Jesper Dangaard Brouer
2013-04-24 22:09 ` Sergei Shtylyov
2013-04-25 10:13 ` Jesper Dangaard Brouer
2013-04-25 12:13 ` Sergei Shtylyov
2013-04-25 19:11 ` David Miller
2013-04-24 23:48 ` Eric Dumazet
2013-04-25 3:26 ` Hannes Frederic Sowa
2013-04-25 19:52 ` [net-next PATCH V2] " Jesper Dangaard Brouer
2013-04-29 17:44 ` David Miller
2013-04-24 15:48 ` [net-next PATCH 3/4] net: avoid false perf interpretations in frag code Jesper Dangaard Brouer
2013-04-24 23:48 ` Eric Dumazet
2013-04-24 23:54 ` David Miller
2013-04-25 10:57 ` Jesper Dangaard Brouer
2013-04-25 19:13 ` David Miller
2013-04-24 15:48 ` [net-next PATCH 4/4] net: frag LRU list per CPU Jesper Dangaard Brouer
2013-04-25 0:25 ` Eric Dumazet
2013-04-25 2:05 ` Eric Dumazet [this message]
2013-04-25 14:06 ` Jesper Dangaard Brouer
2013-04-25 14:37 ` Eric Dumazet
2013-04-25 13:59 ` Jesper Dangaard Brouer
2013-04-25 14:10 ` Eric Dumazet
2013-04-25 14:18 ` Eric Dumazet
2013-04-25 19:15 ` Jesper Dangaard Brouer
2013-04-25 19:22 ` Eric Dumazet
2013-04-24 16:21 ` [net-next PATCH 0/4] net: frag patchset for fixing LRU scalabilityissue David Laight
2013-04-25 11:39 ` Jesper Dangaard Brouer
2013-04-25 12:57 ` David Laight
2013-04-24 17:27 ` [net-next PATCH 0/4] net: frag patchset for fixing LRU scalability issue Hannes Frederic Sowa
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