[ATA] and re(4) stability issues

Pyun YongHyeon pyunyh at gmail.com
Tue Dec 9 22:36:49 PST 2008

On Tue, Dec 09, 2008 at 07:52:37PM +0100, Victor Balada Diaz wrote:
 > Hello,
 > I got various machines[1] at hetzner.de and I've been having problems
 > with interrupts on FreeBSD 7.0 and now FreeBSD 7.1 -BETA2 in amd64. I've
 > been trying to narrow the problem so someone more knowledgeable than me
 > is able to fix it. This mail is an other attempt to ask a question
 > with regards ATA code to see if this time i got something.
 > For the ones that don't actually know what happened:
 > With FreeBSD 7.0 -RELEASE for amd64 and default kernel
 > the system shared re0 interrupt with OHCI and this caused
 > re(4) to corrupt packets and create interrupt storms. Tried

re(4) in 7.0-RELEASE had bus_dma(9) bug which could be easily
triggered on systems with > 4GB memory. But I dont' know whether
this is related with interrupt storms.

 > updating to 7.1 -BETA2 and still had some problems with it.
 > I've opened the PR kern/128287[2] and Remko quickly answered
 > with a workaround: that workaround was removing USB support from
 > my kernel. I did it and re(4) wasn't sharing interrupts anylonger,
 > and the interrupt storms were gone. Now sometime later the interface
 > goes up and down from time to time, but less often. Also sometimes
 > the machine losts the network interface but continues to work.

It seems that your controller supports MSI so you can set a tunable
hw.re.msi_disable to 0 to enable MSI. With MSI you can remove
interrupt sharing(e.g. add hw.re.msi_disable="0" to
/boot/loader.conf file.) However there were several issues on re(4)
w.r.t MSI so it was off by default.

 > I know it continues to work because some days later i can see that
 > it tried to deliver the status reports but was unable to resolve the
 > aliases hostnames. I can't ping the machine and i know the network
 > is OK. If i reboot the machine everything is working again.

Recently I've made small changes to re(4) which may help to detect
link state change event. Would you try re(4) in HEAD?

Pyun YongHyeon

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