From: Zoltan Kiss <zoltan.kiss@linaro.org>
To: Olivier Matz <olivier.matz@6wind.com>,
Zoltan Kiss <zoltan.kiss@schaman.hu>,
dev@dpdk.org
Cc: Bruce Richardson <bruce.richardson@intel.com>
Subject: Re: [dpdk-dev] [PATCH v2] mempool: adjust name string size in related data types
Date: Thu, 21 Jul 2016 14:47:48 +0100 [thread overview]
Message-ID: <34eb5f3b-307a-3072-d262-e46a6437eea7@linaro.org> (raw)
In-Reply-To: <edb8a833-c1fa-a8c8-f156-d515f67cf3a2@6wind.com>
On 21/07/16 14:40, Olivier Matz wrote:
> Hi Zoltan,
>
>
> On 07/20/2016 07:16 PM, Zoltan Kiss wrote:
>> A recent patch brought up an issue about the size of the 'name' fields:
>>
>> 85cf0079 mem: avoid memzone/mempool/ring name truncation
>>
>> These relations should be observed:
>>
>> 1. Each ring creates a memzone with a prefixed name:
>> RTE_RING_NAMESIZE <= RTE_MEMZONE_NAMESIZE - strlen(RTE_RING_MZ_PREFIX)
>>
>> 2. There are some mempool handlers which create a ring with a prefixed
>> name:
>> RTE_MEMPOOL_NAMESIZE <= RTE_RING_NAMESIZE - strlen(RTE_MEMPOOL_MZ_PREFIX)
>>
>> 3. A mempool can create up to RTE_MAX_MEMZONE pre and postfixed memzones:
>> sprintf(postfix, "_%d", RTE_MAX_MEMZONE)
>> RTE_MEMPOOL_NAMESIZE <= RTE_MEMZONE_NAMESIZE -
>> strlen(RTE_MEMPOOL_MZ_PREFIX) - strlen(postfix)
>>
>> Setting all of them to 32 hides this restriction from the application.
>> This patch decreases the mempool and ring string size to accommodate for
>> these prefixes, but it doesn't apply the 3rd constraint. Applications
>> relying on these constants need to be recompiled, otherwise they'll run
>> into ENAMETOOLONG issues.
>> The size of the arrays are kept 32 for ABI compatibility, it can be
>> decreased next time the ABI changes.
>>
>> Signed-off-by: Zoltan Kiss <zoltan.kiss@schaman.hu>
>
> Looks like to be a good compromise for the 16.07 release. One question
> however: why not taking in account the 3rd constraint? Because it may
> not completly fix the issue if the mempool is fragmented.
>
> We could define RTE_MEMPOOL_NAMESIZE to 24
> = 32 - len('mp_') - len('_0123'))
I was trying to figure out a compile time macro for strlen(postfix), but
I could not. Your suggestion would work only until someone increases
RTE_MAX_MEMZONE above 9999. As the likelihood of fragmenting a pool over
99 memzones seems small, I did not bother to fix this with an ugly hack,
but if you think we should include it, let me know!
>
> Thanks,
> Olivier
>
next prev parent reply other threads:[~2016-07-21 13:47 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-19 14:37 [dpdk-dev] [PATCH] mempool: fix lack of free() registration Zoltan Kiss
2016-07-19 14:37 ` [dpdk-dev] [PATCH] mempool: adjust name string size in related data types Zoltan Kiss
2016-07-19 15:37 ` Olivier Matz
2016-07-19 15:59 ` Zoltan Kiss
2016-07-19 16:17 ` Olivier Matz
2016-07-20 12:41 ` Zoltan Kiss
2016-07-20 13:37 ` Olivier Matz
2016-07-20 14:01 ` Richardson, Bruce
2016-07-20 17:20 ` Zoltan Kiss
2016-07-20 17:16 ` [dpdk-dev] [PATCH v2] " Zoltan Kiss
2016-07-21 13:40 ` Olivier Matz
2016-07-21 13:47 ` Zoltan Kiss [this message]
2016-07-21 14:25 ` Olivier Matz
2016-07-21 21:16 ` Thomas Monjalon
2016-07-19 15:26 ` [dpdk-dev] [PATCH] mempool: fix lack of free() registration Olivier Matz
2016-07-19 16:17 ` Zoltan Kiss
2016-07-20 17:14 ` [dpdk-dev] [PATCH v2] mempool: fix lack of free registration Zoltan Kiss
2016-07-21 21:04 ` Thomas Monjalon
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