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Date: Fri, 2 Sep 2016 09:51:43 -0700
From: Stephen Hemminger <stephen@networkplumber.org>
To: Linzhe Lee <slayercat.subscription@gmail.com>
Cc: dev@dpdk.org
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Subject: Re: [dpdk-dev] [PATCH] mbuf: fix atomic refcnt update
 synchronization
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On Sat, 3 Sep 2016 00:31:50 +0800
Linzhe Lee <slayercat.subscription@gmail.com> wrote:

> Thanks for reply, Stephen.
> 
> 
> 
> I'm in x86-64, my cpu is `Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz`.
> 
> 
> 
> When allocation mbuf in program1, and transfer it to program2 for free
> via ring, the program1 might meet assert in allocate mbuf sometimes.
> (`RTE_ASSERT(rte_mbuf_refcnt_read(m) == 0);`)
> 
> 
> 
> but when I using gdb to check it, the refcnt field of mbuf is already
> zero. so I believe the problem came from the cache line problem or
> incorrect optimization.
> 
> 
> 
> When apply this patch, the problem seems solved. I'm submitting it for
> your comments.

Are you sure you have REFCNT_ATOMIC set?