From: Kurt Van Dijck <kurt.van.dijck-/BeEPy95v10@public.gmane.org>
To: Oliver Hartkopp <socketcan-fJ+pQTUTwRTk1uMJSBkQmQ@public.gmane.org>
Cc: socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org,
netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Eric Dumazet
<eric.dumazet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [RFC v3 3/6] can: make struct proto const
Date: Tue, 15 Mar 2011 23:12:53 +0100 [thread overview]
Message-ID: <20110315221253.GA380@e-circ.dyndns.org> (raw)
In-Reply-To: <4D7FD9ED.1080004-fJ+pQTUTwRTk1uMJSBkQmQ@public.gmane.org>
On Tue, Mar 15, 2011 at 10:28:13PM +0100, Oliver Hartkopp wrote:
> On 14.03.2011 18:17, Kurt Van Dijck wrote:
> > On Mon, Mar 14, 2011 at 05:42:23PM +0100, Eric Dumazet wrote:
> >> Le lundi 14 mars 2011 à 16:02 +0100, Kurt Van Dijck a écrit :
> >>
> >>> I see your point.
> >>> The reason I modified this was, as described, checkpatch.pl was complaining.
> >>> Anyway, this sequence was protected by a spinlock 'proto_tab_lock'.
> >>> I don't think it was a race.
> >>>
> >>> Did I miss something?
> >>
> >> As soon as proto_tab[proto] = cp; is done, another thread on another cpu
> >> can read the pointer and follow it.
> >>
> >> Hmm, I missed can_create() also uses the spinlock protection, so you're
> >> probably right.
> >>
> >> It seems a bit overkill :(
> >> phonet uses RCU for example.
>
> Hello Eric,
>
> the RCU code in phonet is worth to consider. But loading and removing of
> protocols is far away from being a hot path ... what would be the advantages
> to move to RCU here?
Does RCU avoid a spinlock?
>
> > I'll keep that in mind.
> > Switching CAN protos to RCU is far beyond to goal of this patch :-)
>
> Anyway making the struct proto a const (and set the default defines in the CAN
> protocols) is a nice cleanup. Let's wait for the feedback about the RCU from
> Eric ... then this patch could be put into mainline independently from the
> j1939 protocol.
ack.
Kurt
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next prev parent reply other threads:[~2011-03-15 22:12 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-14 13:20 [RFC v3 0/6] CAN: add SAE J1939 protocol Kurt Van Dijck
[not found] ` <20110314132004.GA333-MxZ6Iy/zr/UdbCeoMzGj59i2O/JbrIOy@public.gmane.org>
2011-03-14 13:24 ` [RFC v3 1/6] can: extend sockaddr_can to include j1939 members Kurt Van Dijck
2011-03-14 14:15 ` Eric Dumazet
2011-03-14 14:53 ` Kurt Van Dijck
2011-03-14 13:26 ` [RFC v3 2/6] can: add rtnetlink support Kurt Van Dijck
2011-03-14 13:47 ` [RFC v3 3/6] can: make struct proto const Kurt Van Dijck
2011-03-14 14:09 ` Eric Dumazet
2011-03-14 15:02 ` Kurt Van Dijck
2011-03-14 16:42 ` Eric Dumazet
2011-03-14 17:17 ` Kurt Van Dijck
2011-03-15 21:28 ` Oliver Hartkopp
[not found] ` <4D7FD9ED.1080004-fJ+pQTUTwRTk1uMJSBkQmQ@public.gmane.org>
2011-03-15 22:12 ` Kurt Van Dijck [this message]
2011-03-15 22:19 ` Eric Dumazet
2011-03-14 13:56 ` [RFC v3 4/6] j1939: initial import of SAE J1939 Kurt Van Dijck
2011-03-14 13:59 ` [RFC v3 5/6] j1939: add documentation and MAINTAINERS Kurt Van Dijck
[not found] ` <20110314135917.GF333-MxZ6Iy/zr/UdbCeoMzGj59i2O/JbrIOy@public.gmane.org>
2011-03-20 15:56 ` Oliver Hartkopp
[not found] ` <4D8623BE.2080807-fJ+pQTUTwRTk1uMJSBkQmQ@public.gmane.org>
2011-03-25 13:55 ` Kurt Van Dijck
2011-03-29 14:29 ` SAE J1939: update Kurt Van Dijck
2011-03-29 19:41 ` Oliver Hartkopp
2011-04-13 4:49 ` [RFC v3 5/6] j1939: rename NAME to UUID? Kurt Van Dijck
[not found] ` <20110413044928.GA289-ozGf4kBk5synFtIcQ8t7k3L8HoS0Hn3T@public.gmane.org>
2011-04-15 17:57 ` Oliver Hartkopp
[not found] ` <4DA88705.5040203-fJ+pQTUTwRTk1uMJSBkQmQ@public.gmane.org>
2011-04-20 7:10 ` Kurt Van Dijck
2011-04-20 7:24 ` Kurt Van Dijck
[not found] ` <20110420072439.GB332-ozGf4kBk5synFtIcQ8t7k3L8HoS0Hn3T@public.gmane.org>
2011-04-20 10:59 ` Oliver Hartkopp
[not found] ` <4DAEBC94.5020009-fJ+pQTUTwRTk1uMJSBkQmQ@public.gmane.org>
2011-04-21 6:54 ` Kurt Van Dijck
2011-04-22 14:18 ` Kurt Van Dijck
[not found] ` <20110422141832.GB334-ozGf4kBk5synFtIcQ8t7k3L8HoS0Hn3T@public.gmane.org>
2011-04-22 15:14 ` Oliver Hartkopp
[not found] ` <4DB19B46.4000306-fJ+pQTUTwRTk1uMJSBkQmQ@public.gmane.org>
2011-04-23 5:51 ` Kurt Van Dijck
2011-03-14 14:05 ` [RFC v3 6/6] iproute2: add CAN and J1939 rtnetlink support Kurt Van Dijck
2011-03-15 9:23 ` [RFC v3 0/6] CAN: add SAE J1939 protocol Kurt Van Dijck
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