From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: Zoltan Kiss <zoltan.kiss@schaman.hu>
Cc: dev@dpdk.org, Olivier Matz <olivier.matz@6wind.com>,
Zoltan Kiss <zoltan.kiss@linaro.org>,
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 23:16:21 +0200 [thread overview]
Message-ID: <5162614.6uImdtqVO2@xps13> (raw)
In-Reply-To: <1e8aa5d1-b83e-5e35-e382-b0cc685ffb56@6wind.com>
2016-07-21 16:25, Olivier Matz:
> On 07/21/2016 03:47 PM, Zoltan Kiss wrote:
> > On 21/07/16 14:40, Olivier Matz wrote:
> >> 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!
>
> Ok, looks fair, thanks for the clarification.
>
> Acked-by: Olivier Matz <olivier.matz@6wind.com>
Applied, thanks
next prev parent reply other threads:[~2016-07-21 21:16 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
2016-07-21 14:25 ` Olivier Matz
2016-07-21 21:16 ` Thomas Monjalon [this message]
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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