Re: Anyone recall the dreaded tstile issue?

[Patrick Welche <prlw1%talktalk.net@localhost>]

Having not seen the dreaded turnstile issue in ages, a NetBSD-9.99.99/amd64
got stuck on shutdown last night with:

db{0}> ps
PID    LID S CPU     FLAGS       STRUCT LWP *               NAME WAIT
4761  4761 3   0         0   ffff83a478576940               sync tstile
5499  5499 3   1        40   ffff83a486cb2740               halt tstile
5262  5262 3   0       180   ffff83a4862ecac0             pickup kqueue
4060  4060 3   0        40   ffff83a486cb2300               halt tstile
...

Today's very unusual use pattern was that I created several 5GB
files in its large tmpfs /tmp and then moved them to a ZFS partition.

As I recollect, I then did a git log in github/netbsd/src, and nothing
happened. top showed pagedaemon at 100%. ^C in the git xterm eventually
returned, so no more git process.

From memory, doing a bt/a on pgdaemon's *lwp just showed
uvm_pageout
uvm_availmem

Things carried on for a while, and a subsequent git log worked, but
then mutt got stuck in tstile. AFAIR it was the only process in
tstile. I then shutdown -p now. Wondered why not much was happening.
Repeated the shutdown in the same xterm which was still responsive.
ddb then showed me the above. Evenutally I hit the power-off switch.

So for me, no PUFFS was involved, but git, tmpfs, ZFS were.


Cheers,

Patrick