Re: ppoll() stuck on POLLIN while TCP peer is sending

Eric Wong
2013-01-03T23:46:01Z

Eric Wong <normalperson@yhbt.net> wrote:
> Eric Dumazet <eric.dumazet@gmail.com> wrote:
> > With the following patch, I cant reproduce the 'apparent stuck'
>
> Right, the output is just an approximation and the logic there
> was bogus.
>
> Thanks for looking at this.

I'm still able to reproduce the issue under v3.8-rc2 with your patch
for toosleepy.

(As expected when blocked,) TCP send() will eventually return
ETIMEOUT when I forget to check (and toosleepy will abort from it)

I think this requires frequent dirtying/cycling of pages to reproduce.
(from copying large files around) to interact with compaction.
I'll see if I can reproduce the issue with read-only FS activity.

With 3.7.1 and compaction/THP disabled, I was able to run ~21 hours
and copy a few TB around without anything getting stuck.