On Wed, Aug 23, 2006 at 06:55:04PM +0900, Pyun YongHyeon wrote: P> On Wed, Aug 23, 2006 at 01:37:41PM +0400, Gleb Smirnoff wrote: P> > On Tue, Aug 22, 2006 at 01:20:23PM +0900, Pyun YongHyeon wrote: P> > P> After fixing em(4) watchdog bug, I looked over bge(4) and I think P> > P> bge(4) may suffer from the same issue. So if you have seen occasional P> > P> watchdog timeout errors on bge(4) please give the attached patch a try. P> > P> The patch does fix false watchdog timeout error only. P> > P> Typical pheonoma for false watchdog timeout error are P> > P> o polling(4) fix the issue P> > P> o random watchdog error P> > P> P> > P> If my patch fix the issue you could see the following messages. P> > P> "missing Tx completion interrupt!" or "link lost -- resetting" P> > P> > I still think that this fix is incorrect. It is just a more gentle P> > recovery from a fake watchdog timeout. P> P> Its sole purpose is to reinitialize hardware for real watchdog P> timeouts. It's not fix for general watchdog timeouts. As I said other P> mails, the fake watchdog timeout(losing Tx interrupts) for hardwares P> with Tx interrupt moderation capability could be normal thing. So I P> just want to know bge(4) also has the same feature(bug). According to several emails about em(4) fake watchdog timeouts, the problem can be fixed by setting debug.mpsafenet=0. This makes me think that the problem isn't caused by TX interrupt moderation, but some race in the kernel. Really, if_slowtimo() doesn't acquire driver lock before checking and modifying the if_timer field. Afaik, NIC drivers that can do interrupt moderation should set a timer to a sane value, based on interrupt moderation settings, so that the watchdog won't be ever called fakely. P> > The more I think, the more I doubt that we really need the P> > watchdog infrastructure that comes from old days. P> P> Would you give other way to recover from Tx stuck condition without P> using watchdog? May be driver should take care of that theirselves, why not? At least the callout routine will have access to the driver mutex, contrary to if_slowtimo(). -- Totus tuus, Glebius. GLEBIUS-RIPN GLEB-RIPEReceived on Wed Aug 23 2006 - 08:04:36 UTC
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