From: ebiederm@xmission•com (Eric W. Biederman)
To: Cong Wang <amwang@redhat•com>
Cc: netdev@vger•kernel.org, "David S. Miller" <davem@davemloft•net>
Subject: Re: [Patch net-next v2] pktgen: support net namespace
Date: Mon, 28 Jan 2013 19:33:58 -0800 [thread overview]
Message-ID: <877gmwirx5.fsf@xmission.com> (raw)
In-Reply-To: <1359428563.20729.12.camel@cr0> (Cong Wang's message of "Tue, 29 Jan 2013 11:02:43 +0800")
Cong Wang <amwang@redhat•com> writes:
> On Mon, 2013-01-28 at 18:36 -0800, Eric W. Biederman wrote:
>> Cong Wang <amwang@redhat•com> writes:
>>
>> > From: Cong Wang <amwang@redhat•com>
>> >
>> > v2: remove a useless check
>> >
>> > This patch add net namespace to pktgen, so that
>> > we can use pktgen in different namespaces.
>> >
>> > Cc: Eric W. Biederman <ebiederm@xmission•com>
>> > Cc: David S. Miller <davem@davemloft•net>
>> > Signed-off-by: Cong Wang <amwang@redhat•com>
>> >
>> > ---
>> > net/core/pktgen.c | 123 +++++++++++++++++++++++++++++++++++------------------
>> > 1 files changed, 81 insertions(+), 42 deletions(-)
>>
>> Skiming through this again I have spotted what looks like a pretty
>> major bug. You are limiting yourself to one network device per network
>> namespace when the actual limit is one network device per thread.
>>
>> I think you can just kill the dev member of pktgen_net and the two or
>> three lines of code that touch it.
>
> Good point!
>
> It is used by pktgen_device_event() to check if the device generates the
> event is the one in our namespace.
Which of course is trivial with dev_net()...;
> It is safe to continue the search even if it is not in our namespace,
> but it is not efficient. Probably we need to make pktgen_threads list
> per-namespace.
Having looked at the code a bit more I think the solution really is to
make the proc files per network namespace as you are doing, but to leave
the threads per cpu. Then it is just a matter of adding for_each_net
loops in the in the paths that add and remove the proc files.
The per interface proc files would of course only show up in a single
network namespace.
It is still a proc file per network namespace and per cpu but that is
better than threads that try and consume cpu resources. Especially
since the threads when runnign try and consume 100% of the cpu for
transmitting packets.
Eric
next prev parent reply other threads:[~2013-01-29 3:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-29 1:53 [Patch net-next v2] pktgen: support net namespace Cong Wang
2013-01-29 2:36 ` Eric W. Biederman
2013-01-29 3:02 ` Cong Wang
2013-01-29 3:33 ` Eric W. Biederman [this message]
2013-01-29 3:54 ` Cong Wang
2013-01-29 4:17 ` Eric W. Biederman
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