Re: [PATCH] virtio-net: fix a race on 32bit arches

On Wed, Jun 06, 2012 at 09:35:04PM +0100, Ben Hutchings wrote:

On Wed, 2012-06-06 at 23:16 +0300, Michael S. Tsirkin wrote:

quoted

On Wed, Jun 06, 2012 at 10:08:09PM +0200, Eric Dumazet wrote:

quoted

On Wed, 2012-06-06 at 22:58 +0300, Michael S. Tsirkin wrote:

quoted

Absolutely, I am talking about virtio here.  I'm not kicking
u64_stats_sync idea I am just saying that simple locking
would work for virtio and might be better as it
gives us a way to get counters atomically.

Which lock do you own in the RX path ?

We can just disable napi, everything is updated from napi callback.

Seriously, though: don't do that; this is going to hurt performance for
minimal benefit.

Ben.

Yea, it doesn't work anyway. Maybe take a xmit lock for tx and keep
using the per-cpu counters for rx. Or does this sound too disruptive
too?

quoted

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You'll have to add a lock in fast path. This sounds really a bad choice
to me.

.ndo_get_stats64 is not data path though, is it?

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.