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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Jarek Poplawski <jarkao2@gmail.com>,
	Stephen Hemminger <shemminger@vyatta.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
	David Miller <davem@davemloft.net>,
	netdev@vger.kernel.org
Subject: [RFC] gro: Is it ok to share a single napi from several devs ?
Date: Sat, 28 Aug 2010 12:54:06 +0200	[thread overview]
Message-ID: <1282992846.2277.15.camel@edumazet-laptop> (raw)
In-Reply-To: <20100828094433.GA3110@del.dom.local>

In commit f2bde7328633269ee935d9ed96535ade15cc348f
Author: Stephen Hemminger <shemminger@vyatta.com>

    net: allow multiple dev per napi with GRO
    
    GRO assumes that there is a one-to-one relationship between NAPI
    structure and network device. Some devices like sky2 share multiple
    devices on a single interrupt so only have one NAPI handler. Rather than
    split GRO from NAPI, just have GRO assume if device changes that
    it is a different flow.
   

It was assumed a napi could be shared by several devs, but I dont really
understand, since we have an unique ->dev pointer inside "napi_struct",
this one is set once, and never change.

This pointer is currently used from napi_get_frags() [but that could be
avoided], and from netpoll_poll_lock().

The netpoll_poll_lock() case is problematic.

static inline void *netpoll_poll_lock(struct napi_struct *napi)
{
        struct net_device *dev = napi->_dev;

        if (dev && dev->npinfo) {
                spin_lock(&napi->poll_lock);

Maybe we should remove 'dev' field from napi_struct and replace it by a
npinfo pointer ?





  reply	other threads:[~2010-08-28 10:54 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-27 20:50 [PATCH] net: Fix vlan_gro_frags vs netpoll and bonding paths Jarek Poplawski
2010-08-28  0:13 ` Herbert Xu
2010-08-28  9:44   ` Jarek Poplawski
2010-08-28 10:54     ` Eric Dumazet [this message]
2010-08-28 14:31       ` [RFC] gro: Is it ok to share a single napi from several devs ? Jarek Poplawski
2010-08-28 14:48         ` Eric Dumazet
2010-08-28 15:16           ` Jarek Poplawski
2010-08-28 17:14           ` Stephen Hemminger
2010-08-28 21:41             ` David Miller
2010-08-28 22:31               ` Stephen Hemminger
2010-08-28 22:33                 ` David Miller
2010-08-29  9:59               ` Jarek Poplawski
2010-08-29 17:06                 ` David Miller
2010-08-29 18:39                   ` Eric Dumazet
2010-08-30  6:42                     ` Jarek Poplawski
2010-08-30 15:57                       ` Stephen Hemminger
2010-08-30 16:50                         ` David Miller
2010-08-30 17:51                           ` [PATCH] sky2: don't do GRO on second port Stephen Hemminger
2010-08-30 19:09                             ` Jarek Poplawski
2010-09-01 21:51                               ` David Miller
2010-09-01 21:55                                 ` Stephen Hemminger
2010-09-02  9:18                                   ` Jarek Poplawski
2010-09-02 12:53                                     ` Jarek Poplawski
2010-09-02 16:30                                       ` David Miller
2010-09-02 16:48                                         ` Jarek Poplawski
2010-09-02  8:33                                 ` Jarek Poplawski
2010-09-02  9:31                                   ` Eric Dumazet
2010-09-02  9:55                                     ` Jarek Poplawski
2010-09-02 10:41                                       ` Eric Dumazet
2010-09-02 11:02                                         ` Jarek Poplawski
2010-09-02 12:09                                           ` Eric Dumazet
2010-09-02 12:28                                             ` Jarek Poplawski
2010-09-02 17:08                                         ` David Miller
2010-09-02 21:26                                         ` Herbert Xu
2010-09-03  5:23                                           ` Eric Dumazet
2010-09-02  9:32                                   ` Jarek Poplawski
2010-08-30 18:36                           ` [RFC] gro: Is it ok to share a single napi from several devs ? Jarek Poplawski
2010-08-30 19:59                             ` [RFC] netpoll: " Eric Dumazet
2010-08-30 20:12                               ` Stephen Hemminger
2010-08-30 20:19                                 ` Eric Dumazet
2010-08-29  4:07 [RFC] gro: " Stephen Hemminger

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