Re: [REGRESSION v5.3] SUNRPC: Replace the queue timer with a delayed work function (7e0a0e38fcfe)

[Trond Myklebust <trondmy@hammerspace.com>]

On Tue, 2019-11-05 at 12:03 +0000, Jon Hunter wrote:
> Hi Trond,
> 
> Any feedback on this?

See the patch I sent this morning. I believe that ought to fix the
problem.
Sorry about the regression. As you saw from the original patch, it
predates your first bug report, and when I queued it up for submission,
I missed that it was copying the "deferrable" status that caused that
first bug.

Cheers
  Trond

> 
> Jon
> 
> On 25/10/2019 08:28, Jon Hunter wrote:
> > Hi Trond,
> > 
> > Similar to the change 431235818bc3 ("SUNRPC: Declare RPC timers as
> > TIMER_DEFERRABLE") I have been tracking down another suspend/NFS
> > related
> > issue where again I am seeing random delays exiting suspend. The
> > delays
> > can be up to a couple minutes in the worst case and this is causing
> > a
> > suspend test we have to fail. For example, with this change I see
> > ...
> > 
> > [  130.599520] PM: suspend entry (deep)
> > 
> > [  130.607267] Filesystems sync: 0.000 seconds
> > 
> > [  130.615800] Freezing user space processes ... (elapsed 0.001
> > seconds) done.
> > 
> > [  130.628247] OOM killer disabled.
> > 
> > [  130.635382] Freezing remaining freezable tasks ... (elapsed
> > 0.001 seconds) done.
> > 
> > [  130.648052] printk: Suspending console(s) (use
> > no_console_suspend to debug)
> > 
> > [  130.686015] Disabling non-boot CPUs ...
> > 
> > [  130.689568] IRQ 17: no longer affine to CPU2
> > 
> > [  130.693435] Entering suspend state LP1
> > 
> > [  130.693489] Enabling non-boot CPUs ...
> > 
> > [  130.697108] CPU1 is up
> > 
> > [  130.700602] CPU2 is up
> > 
> > [  130.704338] CPU3 is up
> > 
> > [  130.781259] mmc1: queuing unknown CIS tuple 0x80 (50 bytes)
> > 
> > [  130.789742] mmc1: queuing unknown CIS tuple 0x80 (7 bytes)
> > 
> > [  130.792793] mmc1: queuing unknown CIS tuple 0x80 (7 bytes)
> > 
> > [  130.820913] mmc1: queuing unknown CIS tuple 0x02 (1 bytes)
> > 
> > [  131.345569] OOM killer enabled.
> > 
> > [  131.352643] Restarting tasks ... done.
> > 
> > [  131.365480] PM: suspend exit
> > 
> > [  134.524261] asix 1-1:1.0 eth0: link up, 100Mbps, full-duplex,
> > lpa 0xCDE1
> > 
> > [  243.745788] nfs: server 192.168.99.1 not responding, still
> > trying
> > 
> > [  243.745811] nfs: server 192.168.99.1 not responding, still
> > trying
> > 
> > [  243.767939] nfs: server 192.168.99.1 not responding, still
> > trying
> > 
> > [  243.778233] nfs: server 192.168.99.1 OK
> > 
> > [  243.787058] nfs: server 192.168.99.1 OK
> > 
> > [  243.787542] nfs: server 192.168.99.1 OK
> > 
> > 
> > Running a git bisect I was able to track it down to the commit
> > referenced
> > in the $subject. Reverting this on top of the current mainline
> > fixes the
> > problem and I no longer see these long delays.
> > 
> > Cheers
> > Jon
> > 
-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com