netdev - Re: [PATCH v2 2/3] mac80211: mesh: improve path resolving time

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Message-ID: <1470921732.12075.18.camel@sipsolutions.net>
Date:	Thu, 11 Aug 2016 15:22:12 +0200
From:	Johannes Berg <johannes@...solutions.net>
To:	Bob Copeland <me@...copeland.com>, Yaniv Machani <yanivma@...com>
Cc:	linux-kernel@...r.kernel.org, Maital Hahn <maitalm@...com>,
	"David S. Miller" <davem@...emloft.net>,
	linux-wireless@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: [PATCH v2 2/3] mac80211: mesh: improve path resolving time

On Tue, 2016-07-19 at 08:36 -0400, Bob Copeland wrote:
> On Wed, Jul 13, 2016 at 02:45:25PM +0300, Yaniv Machani wrote:
> > 
> > When a packet is received for transmission,
> > a PREQ frame is sent to resolve the appropriate path to the desired
> > destination.
> > After path was established, any sequential PREQ will be sent only
> > after
> > dot11MeshHWMPpreqMinInterval, which usually set to few seconds.
> > 
> > This implementation has an impact in cases where we would like to
> > resolve the path quickly.
> > A clear example is when a peer was disconnected from us,
> > while he acted as a hop to our destination.
> > Although the path table will be cleared, the next PREQ frame will
> > be sent only after reaching the MinInterval.
> > This will cause unwanted delay, possibly of few seconds until the
> > traffic will resume.
> > 
> >  	if (!(mpath->flags & MESH_PATH_RESOLVING))
> > -		mesh_queue_preq(mpath, PREQ_Q_F_START);
> > +		mesh_queue_preq(mpath, PREQ_Q_F_START, true);
> 
> What about something like this here instead:
> 
>     if (!(mpath->flags & MESH_PATH_RESOLVING)) {
>         /* force next preq to be sent without delay */
>         ifmsh->last_preq = jiffies - min_preq_int_jiff(sdata) - 1;
>         mesh_queue_preq(mpath, PREQ_Q_F_START);
>     }
> 

Yaniv, did you disagree with this for some strong reason, or were you
going to resend?

Having a smaller patch seems nicer too.

johannes