Re: [PATCH 0/5] Re: [Intel-gfx] [BUG][REGRESSION] i915 gpu hangs under load

From: Martin Kepplinger
Date: Mon Apr 10 2017 - 06:15:44 EST


Am 07.04.2017 01:23 schrieb Andrea Arcangeli:
I'm also getting kernel hangs every couple of days. For me it's still
not fixed here in 4.11-rc5. It's hard to reproduce, the best
reproducer is to build lineageos 14.1 on host while running LTP in a
guest to stress the guest VM.

Initially I thought it was related to the fact I upgraded the xf86
intel driver just a few weeks ago (I deferred any upgrade of the
userland intel driver since last July because of a regression that
never got fixed and broke xterm for me). After I found a workaround
for the userland regression (appended at the end for reference) I
started getting kernel hangs but they are separate issues as far as I
can tell.

It's not well tested so beware... (it survived a couple of builds and
some VM reclaim but that's it).

The first patch 1/5 is the potential fix for the i915 kernel hang. The
rest are incremental improvements.

And I've no great solution for when the shrinker was invoked with the
struct_mutex held and and recurse on the lock. I don't think we can
possibly wait in such case (other than flush work that the second
patch does) but then practically it shouldn't be a big deal, the big
RAM eater is unlikely to be i915 when the system is low on memory.


FWIW without having insight here, -rc6 seems to be good.
No disturbing gpu hangs under load so far.