On Mon, Sep 17, 2018 at 10:19 AM, <mcatanzaro(a)gnome.org> wrote:
On Mon, Sep 17, 2018 at 9:07 AM, Matthew Miller
> I think the issue is that it's it's _possible_ that a out-of-control
> could suddenly eat up a bunch of memory and go to swap right at the wrong
> time. If there's enough space, this is unlikely in practical use. I'm not
> super worried, because realistically that out-of-control processes and
> runaway swap thrashing was going to take your system down or at the very
> least trigger OOM killing *anyway*.
Matthew, this happens *all the time* to me and to other developers I work
with when building software. All the time. I fine-tune my ninjaargs to
figure out the highest -j I can use when building without killing my
desktop. We shouldn't have to do this. We're not talking about out of
control processes, we're talking about running make or ninja exactly as
designed: it's expected to spawn a huge number of GCC subprocesses (4, 8,
32...), each one will want 1-2 GB of RAM... the Fedora desktop should remain
smooth and performant under this load and throttle ninja as needed, not
If zram or zswap will help such that the desktop doesn't freeze up, then
great, let's try that.
[root@f29h ~]# cat /proc/sys/vm/swappiness
This is now widely regarded as sabotage, because it's simply too
aggressive for the amount of RAM we have these days compared to 4MB of
RAM. Upstream is unlikely to change it, they've been beaten over the
head for years about it.
# echo 1 > /proc/sys/vm/swappiness
Now do whatever normally blows things up, and report back. I'm kinda
curious. If the problem is simply too aggressive swapping, then
neither zram nor zswap will make that much of a difference (it will
moderate the transition to depending on swap, but once it's
pathological, you'll still be screwed if this is really just a
workload for which swappiness 60 is flat out bad).