Re: malloc message with nfs transfer

From: cosmin <cosmin_at_nacom.phy.uic.edu>
Date: Thu, 21 Aug 2003 15:46:52 -0500
On Thu, Aug 21, 2003 at 02:37:34PM -0400, Robert Watson wrote:
> 
> On Thu, 21 Aug 2003, cosmin wrote:
> 
> > malloc() of "64" with the following non-sleepable locks held:  exclusive
> > sleep mutex inpr = 0 (0xc4444ef0) locked _at_
> > /usr/src/sys/netinet/udp_usrreq.c:378 exclusive sleep mutex netisr lock
> > r = 0 (0xc061be80) locked _at_ /usr/src/sys/net/netisr.c:215
> > 
> > I'm getting those on the console, and it seems that they only happen
> > when users start an nfs transfer to the nfs exported filesystem.  The
> > exported filesystem is a vinum raid5 array but I don't know if that has
> > anything to do with the messages.
> 
> Sorry, just to be clear -- is the message you're getting on the NFS
> client, or the NFS server?  Could you turn on debug.witness_ddb and get a
> stack trace for the warning?

This is on the NFS server.  I turned on debug.witness_ddb, but I'm not sure if this will help, because the system isn't locking up, or otherwise stopping.  I have tried setting a breakpoint in ddb for 0xc4444ef0, but it starts breaking right away.  The malloc() messages are many minutes apart.

I'm not sure if these messages indicate anything critical.  I was mainly concerned with the nfs performance.

I tried reading the developer's handbook to figure out how to make it break only when there's a malloc message but right now I'm stuck.

> 
> > Before I upgraded from 4.8, I used to be able to send at about 8mb/s to
> > the nfs exported raid5.  After upgrading to 5.1-CURRENT, the maximum
> > speed has been only 4mb/s.  I'm wondering if the messages above have
> > anything to do with the performance drop. 
> 
> You appear to have the kernel debugging features turned to high (which
> will be useful for resolving this problem :-).  Turn off WITNESS and
> INVARIANTS and you should see a substantial performance improvement.  It
> may not be back up to 4.x levels -- we hope that with ongoing network
> stack locking work we'll be back to 4.x (and exceed them) in the next few
> months.
> 
> Thanks,
> 
> Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
> robert_at_fledge.watson.org      Network Associates Laboratories
> 
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Received on Thu Aug 21 2003 - 11:46:56 UTC

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