Date: Tue, 19 Apr 2005 16:03:24 +0400 From: Gleb Smirnoff <glebius@FreeBSD.org> To: Andre Oppermann <andre@FreeBSD.org> Cc: net@FreeBSD.org Subject: Re: if_link_state_change() patch for review Message-ID: <20050419120324.GA5862@cell.sick.ru> In-Reply-To: <4264D430.D39B81D0@freebsd.org> References: <20050419064747.GC734@cell.sick.ru> <4264D430.D39B81D0@freebsd.org>
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Andre, On Tue, Apr 19, 2005 at 11:49:36AM +0200, Andre Oppermann wrote: A> > we are working on fixing LORs in if_link_state_change() path, and A> > adding possibility to call if_link_state_change() pseudorecursively, A> > when link of interface depends on link of the other. A> > A> > I'm posting this patch for wider review. An important point about it A> > is that, if several link events occur VERY quickly, only the last one A> > will be processed. I don't know of any software that will be broken by A> > such behavoir. If you know some, please tell me. A> A> I assume this is per interface and not for all interfaces together. Yes, sure. A> You have to be careful here indeed. If the link is rapidly flapping A> then you only want to report changes in status. For example when A> it going down, up, down and all these events got queued it doesn't A> make sense to report down->down. This could indeed confuse some A> tools and isn't very useful. Either you check the first event vs. A> the last one if there is a change in state or you just take the events A> as trigger to have a look at the interface status when the ithread A> runs. There however you'd have to track the previous state to detect A> changes. I do not know any applications which would be confused, yet. Also, while event coalescing is possible theoretically, I failed to reproduce it. I've added a debugging printf, so we will see if anyone experiences these coalescing events at all. -- Totus tuus, Glebius. GLEBIUS-RIPN GLEB-RIPE
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