All of lore.kernel.org
 help / color / mirror / Atom feed
From: Eric Dumazet <eric.dumazet@gmail.com>
To: Jarek Poplawski <jarkao2@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>,
	Tom Herbert <therbert@google.com>,
	Linux Netdev List <netdev@vger.kernel.org>
Subject: Re: [PATCH net-next-2.6] net: Xmit Packet Steering (XPS)
Date: Fri, 20 Nov 2009 23:21:08 +0100	[thread overview]
Message-ID: <4B071654.6040300@gmail.com> (raw)
In-Reply-To: <20091120220851.GA4717@ami.dom.local>

Jarek Poplawski a écrit :
> On Fri, Nov 20, 2009 at 10:43:55PM +0100, Eric Dumazet wrote:
>>> Hmm... Actually, why did I have to do lockdep's job...
>> In fact I could not find why irq masking is necessary, and lockdep is
>> fine with my code and my testings. Care to explain what problem you spotted ?
>>
> 
> CPU1						 CPU2
> net_rx_action()					 net_rx_action()
>  xps_flush()				  	  xps_flush()
>   q = &per_cpu(xps_pcpu_queue, cpu2)		   q = &per_cpu(xps_pcpu_queue, cpu1)
>   spin_lock(&q->list.lock of cpu2)		   spin_lock(&q->list.lock of cpu1)
> 
> <IPI>						 <IPI>
> remote_free_skb_list()				 remote_free_skb_list()
> waiting on spin_lock(&q->list.lock of cpu1)	 waiting on spin_lock(&q->list.lock of cpu2)
> 
> 
> IPIs triggerered e.g. by CPU3 (or/and CPU4...) doing net_rx_action as well.
> 

:) Now I am convinced :)

Thanks jarek



  reply	other threads:[~2009-11-20 22:21 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-19 23:46 [PATCH net-next-2.6] net: Xmit Packet Steering (XPS) Eric Dumazet
2009-11-20  2:12 ` Changli Gao
2009-11-20  4:58   ` Eric Dumazet
2009-11-20  5:11     ` Changli Gao
2009-11-20  5:24       ` Eric Dumazet
2009-11-20  5:34         ` Changli Gao
2009-11-20  5:42           ` Eric Dumazet
2009-11-20  5:50             ` Changli Gao
     [not found] ` <65634d660911191641o4210a797mf1e8168dd8dd8b60@mail.gmail.com>
2009-11-20  5:08   ` Eric Dumazet
2009-11-20 13:32 ` Jarek Poplawski
2009-11-20 14:45   ` Eric Dumazet
2009-11-20 20:04     ` Jarek Poplawski
2009-11-20 21:43       ` Eric Dumazet
2009-11-20 22:08         ` Jarek Poplawski
2009-11-20 22:21           ` Eric Dumazet [this message]
2009-11-20 20:51 ` Andi Kleen
2009-11-20 20:53   ` David Miller
2009-11-20 22:30   ` Eric Dumazet
2009-11-20 22:37     ` Andi Kleen
     [not found]       ` <65634d660911201642k3930dc78vd576e0e89dc0c794@mail.gmail.com>
2009-11-21  6:58         ` Eric Dumazet
2009-11-20 20:53 ` Jarek Poplawski
2009-11-20 21:35   ` Eric Dumazet
2009-11-20 21:43     ` Joe Perches
2009-11-20 21:49       ` David Miller
2009-11-20 22:01       ` Eric Dumazet
2009-11-20 22:34     ` David Miller
2009-11-20 22:32 ` David Miller
2009-11-20 22:36   ` Eric Dumazet

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4B071654.6040300@gmail.com \
    --to=eric.dumazet@gmail.com \
    --cc=davem@davemloft.net \
    --cc=jarkao2@gmail.com \
    --cc=netdev@vger.kernel.org \
    --cc=therbert@google.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.