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Date: Wed, 8 Nov 2023 10:49:22 -0800
From: Tyler Retzlaff <roretzla@linux.microsoft.com>
To: Thomas Monjalon <thomas@monjalon.net>
Cc: dev@dpdk.org, Bruce Richardson <bruce.richardson@intel.com>,
 David Hunt <david.hunt@intel.com>,
 Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>,
 Jerin Jacob <jerinj@marvell.com>,
 Konstantin Ananyev <konstantin.v.ananyev@yandex.ru>,
 Sameh Gobriel <sameh.gobriel@intel.com>,
 Sunil Kumar Kori <skori@marvell.com>,
 Vladimir Medvedkin <vladimir.medvedkin@intel.com>,
 Yipeng Wang <yipeng1.wang@intel.com>
Subject: Re: [PATCH 0/5] use rte atomic thread fence
Message-ID: <20231108184922.GB21615@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
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 <2796747.XrmoMso0CX@thomas>
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On Wed, Nov 08, 2023 at 06:04:47PM +0100, Thomas Monjalon wrote:
> 02/11/2023 04:04, Tyler Retzlaff:
> > Replace use of __atomic_thread_fence with __rte_atomic_thread_fence.
> > 
> > It may be appropriate to use rte_atomic_thread_fence instead but it
> > will be up to maintainers to evaluate and make the change if appropriate.
> 
> I don't understand the use of __rte_atomic_thread_fence
> which is supposed to be EAL-internal only, isn't it?
> 
> On x86, we have this:
> static __rte_always_inline void
> rte_atomic_thread_fence(rte_memory_order memorder)
> {
>     if (memorder == rte_memory_order_seq_cst)
>         rte_smp_mb();
>     else
>         __rte_atomic_thread_fence(memorder);
> }
> 
> This is skipped if you use __rte_atomic_thread_fence() directly.

correct. that is on purpose because the original code was skipping
condition by using __atomic_thread_fence directly.

this series intends no functional change which is why the replacements
are __rte_atomic_thread_fence instead of to rte_atomic_thread_fence.

i would encourage the maintainers to evaluate whether the code can use
rte_atomic_thread_fence directly without functional regression.

ty