netdev - Re: [PATCH net-next] net: updating dst lastusage is an unlikely event.

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Message-Id: <20171027.115354.2129010929524093978.davem@davemloft.net>
Date:   Fri, 27 Oct 2017 11:53:54 +0900 (KST)
From:   David Miller <davem@...emloft.net>
To:     pabeni@...hat.com
Cc:     netdev@...r.kernel.org, weiwan@...gle.com, kafai@...com,
        hannes@...essinduktion.org
Subject: Re: [PATCH net-next] net: updating dst lastusage is an unlikely
 event.

From: Paolo Abeni <pabeni@...hat.com>
Date: Tue, 24 Oct 2017 12:41:01 +0200

> Since commit 0da4af00b2ed ("ipv6: only update __use and lastusetime
> once per jiffy at most"), updating the dst lastuse field is an
> unlikely action: it happens at most once per jiffy, out of
> potentially millions of calls per second.
> 
> Mark explicitly the code as such, and let the compiler generate
> better code.
> 
> Note: gcc 7.2 and several older versions do actually generate
> different - better - code when the unlikely() hint is in place,
> avoid jump in the fast path and keeping better code locality.
> 
> Signed-off-by: Paolo Abeni <pabeni@...hat.com>

Applied, thanks.