netdev - Re: [net-next PATCH] igb: update adapter stats when reading /proc/net/dev.

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Date:	Tue, 05 Oct 2010 23:01:19 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Jesper Dangaard Brouer <hawk@...x.dk>
Cc:	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
	Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: Re: [net-next PATCH] igb: update adapter stats when reading
 /proc/net/dev.

Le mardi 05 octobre 2010 à 17:19 +0200, Eric Dumazet a écrit :
> Le mardi 05 octobre 2010 à 16:53 +0200, Jesper Dangaard Brouer a écrit :
> 
> > Its already racy, because "ethtool -S" reads out the stats immediately,
> > and thus races with the timer.
> > 
> > See: igb_ethtool.c
> >  igb_get_ethtool_stats() invoke igb_update_stats(adapter);
> > 
> 
> You would be surprised how many bugs are waiting to be found and
> fixed ;)
> 
> 

I took a look at igb stats, and it appears they also are racy on 32bit
arches. igb uses u64 counters, with no synchronization between
producers(writers) and consumers(readers).

Some fixes are needed ;)



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