netdev - Re: [PATCH net-next] udp: do rmem bulk free even if the rx sk queue is empty

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Message-Id: <20170920.142914.865968677643614093.davem@davemloft.net>
Date:   Wed, 20 Sep 2017 14:29:14 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     pabeni@...hat.com
Cc:     netdev@...r.kernel.org, edumazet@...gle.com
Subject: Re: [PATCH net-next] udp: do rmem bulk free even if the rx sk
 queue is empty

From: Paolo Abeni <pabeni@...hat.com>
Date: Tue, 19 Sep 2017 12:11:43 +0200

> The commit 6b229cf77d68 ("udp: add batching to udp_rmem_release()")
> reduced greatly the cacheline contention between the BH and the US
> reader batching the rmem updates in most scenarios.
> 
> Such optimization is explicitly avoided if the US reader is faster
> then BH processing.
> 
> My fault, I initially suggested this kind of behavior due to concerns
> of possible regressions with small sk_rcvbuf values. Tests showed
> such concerns are misplaced, so this commit relaxes the condition
> for rmem bulk updates, obtaining small but measurable performance
> gain in the scenario described above.
> 
> Signed-off-by: Paolo Abeni <pabeni@...hat.com>

Applied, thanks Paolo.