[dpdk-dev] [PATCH] mbuf: fix atomic refcnt update synchronization

[Linzhe Lee]

yes,stephen.

my config file here: http://pastebin.com/N0RKGArh

2016-09-03 0:51 GMT+08:00 Stephen Hemminger <stephen at networkplumber.org>:
> On Sat, 3 Sep 2016 00:31:50 +0800
> Linzhe Lee <slayercat.subscription at 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?