From mboxrd@z Thu Jan  1 00:00:00 1970
From: Olivier MATZ <olivier.matz@6wind.com>
Subject: Re: [PATCH,
 v2] mempool: avoid memory waste with large pagesize
Date: Thu, 10 Mar 2016 12:12:12 +0100
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References: <1457557926-4056-1-git-send-email-stephen@networkplumber.org>
 <56E1325C.2030206@6wind.com> <56E150FD.2090403@intel.com>
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>> It still does not work. When CONFIG_RTE_LIBRTE_MEMPOOL_DEBUG=y:
>>
>> mp = rte_mempool_create("test", 128,
>> 	64, 0, 0, NULL, NULL, NULL, NULL, SOCKET_ID_ANY, 0);
>> rte_mempool_dump(stdout, mp);
>>
>>   populated_size=128
>>   header_size=64
>>   elt_size=64
>>   trailer_size=64
>>   total_obj_size=192
>>
> With --no-huge (since patch updates that part), it gives:
>   header_size=64
>   elt_size=64
>   trailer_size=0
>   total_obj_size=128
>   private_data_size=3904
> 
> 1- private_data still rounds to page size, not sure if this is a problem.
> 2- with MEMPOOL_DEBUG=y, trailer_size is 0, comment in code says it
> should keep cookie, not sure if this is a problem.

Yes the trailer should at least be 8 bytes to store the cookie.