Never mind, I was wrong. qdisc run will be invoked by cpu0; i.e: CPU0 CPU1 + grab qlock | | + find that return code is 0 | enq pkt X + release qdisc running | | + grab qdisc running | ==> outta here | call qdisc_run + release qlock
Should have looked at my netconf slides first ;-> cheers, jamal On Thu, 2007-10-05 at 08:21 -0400, jamal wrote: > On Thu, 2007-10-05 at 04:55 -0700, David Miller wrote: > > From: Herbert Xu <[EMAIL PROTECTED]> > > Date: Thu, 10 May 2007 21:50:39 +1000 > > > > > T_SCHED]: Rationalise return value of qdisc_restart > > > > > > The current return value scheme and associated comment was invented > > > back in the 20th century when we still had that tbusy flag. Things > > > have changed quite a bit since then (even Tony Blair is moving on > > > now, not to mention the new French president). > > > > > > All we need to indicate now is whether the caller should continue > > > processing the queue. Therefore it's sufficient if we return 0 if > > > we want to stop and non-zero otherwise. > > > > > > This is based on a patch by Krishna Kumar. > > > > > > Signed-off-by: <[EMAIL PROTECTED]> > > > > Fair enough, patch applied :-) > > Ok, see if this makes sense: > > CPU0 CPU1 (holding qdisc running) > . | > . | > . + grab qlock > . | > . | deq pkt > . + release qlock > . + grab txlock > . | send pkt > . + release txlock > . + grab qlock > has pktX | (NEW: qlen = 0); return 0 instead of -1 > waiting for qlock + release qlock > + grab qlock | > | + find that return code is 0 > | enq pkt X + release qdisc running > | | > + release qlock | ==> outta here > > pkt X is stuck unless some event happens such as a new pkt arrival. > In other words it sits there for an indeterminate period. > > cheers, > jamal - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
