Date: Fri, 27 Jan 2006 16:43:08 -0800
From: Andrew Morton <akpm@osdl.org>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: kiran@scalex86.org, davem@davemloft.net, linux-kernel@vger.kernel.org,
       shai@scalex86.org, netdev@vger.kernel.org, pravins@calsoftinc.com
Subject: Re: [patch 3/4] net: Percpufy frequently used variables --
 proto.sockets_allocated
Message-Id: <20060127164308.1ea4c3e5.akpm@osdl.org>
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Eric Dumazet <dada1@cosmosbay.com> wrote:
>
> > 
> > An advantage of retaining a spinlock in percpu_counter is that if accuracy
> > is needed at a low rate (say, /proc reading) we can take the lock and then
> > go spill each CPU's local count into the main one.  It would need to be a
> > very low rate though.   Or we make the cpu-local counters atomic too.
> 
> We might use atomic_long_t only (and no spinlocks)

Yup, that's it.

> Something like this ?
> 

It'd be a lot neater if we had atomic_long_xchg().

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