Re: multipath patches

From: Trond Myklebust <trondmy@hammerspace.com>
To: "aglo@umich.edu" <aglo@umich.edu>
Cc: "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
	"neilb@suse.com" <neilb@suse.com>
Subject: Re: multipath patches
Date: Thu, 11 Jul 2019 21:13:34 +0000	[thread overview]
Message-ID: <f614be728542c2cb9dd026a5e97b78d4e74a30af.camel@hammerspace.com> (raw)
In-Reply-To: <CAN-5tyG0jdyn8C11v6b8=v3d1p=WoMAhXrAw8mWGEUn-TVXJ=g@mail.gmail.com>

On Thu, 2019-07-11 at 16:33 -0400, Olga Kornievskaia wrote:
> On Thu, Jul 11, 2019 at 3:29 PM Trond Myklebust <
> trondmy@hammerspace.com> wrote:
> > On Thu, 2019-07-11 at 15:06 -0400, Olga Kornievskaia wrote:
> > > Hi Trond,
> > > 
> > > I see that you have nconnect patches in your testing branch (as
> > > well
> > > as your linux-next and I assume they are the same).  There is
> > > something wrong with that version. A mount hangs the machine.
> > > 
> > > [  132.143379] watchdog: BUG: soft lockup - CPU#0 stuck for 23s!
> > > [mount.nfs:2624]
> > > 
> > > I don't have such problems with the patch series that Neil has
> > > posted.
> > > 
> > > Thank you.
> > 
> > How are the patchsets different? As far as I know, all I did was
> > apply
> > the 3 patches that Neil added to my existing branch.
> 
> I'm not sure. I had a problem with your "multipath" branch before and
> I recall what I did is went back and redownloaded your posted
> patches.
> That was when I was testing performance. So if you haven't touched
> that branch and just used it I think it's the same problem.
> 
> In the current testing branch I don't see several patches that Neil
> has added (posted) to the mailing list. So I'm not sure what you mean
> you added 3 of his patches on top of yours. At most I can say maybe
> you added 2 of his (one that allows for v2 and v3 and another that
> does state operations on a single connection. There are no patches
> for
> sunrpc stats that were posted).
> 
> What I know is that if I revert your branch to
> bf11fbdb20b385157b046ea7781f04d0c62554a3 before patches and apply
> Neils patches. All is fine. I really don't want to debug a non-
> working
> version when there is one that works.

Sure, but that is not really an option given the rules for how trees in
linux-next are supposed to work. They are considered to be more or less
stable.

Anyhow, I think I've found the bug. Neil had silently fixed it in one
of my patches, so I've added an incremental patch that does more or
less what he did.

-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com