[systemd-devel] Antw: Re: is the watchdog useful?

[Ulrich Windl]

>>> Pekka Paalanen <ppaalanen at gmail.com> schrieb am 22.10.2019 um 08:54 in
Nachricht <20191022095431.7230c5c7 at eldfell.localdomain>:
> On Mon, 21 Oct 2019 17:50:44 +0000
> Zbigniew Jędrzejewski-Szmek <zbyszek at in.waw.pl> wrote:
> 
>> In principle, the watchdog for services is nice. But in practice it seems
>> be bring only grief. The Fedora bugtracker is full of automated reports of

> ABRTs,
>> and of those that were fired by the watchdog, pretty much 100% are bogus,
in 
> 
>> the sense that the machine was resource starved and the watchdog fired.
> 
> Hi,
> 
> just curious, is that resource starvation caused by something big, e.g.
> a browser, using too much memory which leads to the kernel reclaiming
> also pages of program text sections because they can be reloaded from
> disk at any time, however those pages are needed again immediately
> after when some CPU core switches process context, leading to something
> that looks like a hard freeze to a user, while the kernel is furiously
> loading pages from disk just to drop them again, and can take from
> minutes to hours before any progress is visible?
> 
> It has happened to me on Fedora in the past. I could probably dig up
> discussions about the problem in general if you want, they explain it
> better than I ever could.
> 
> Does Fedora prevent that situation by tuning some kernel knobs nowadays
> for desktops?

It's easy to restrict the allowable VM size (memory.limit_in_bytes) using
cgroups.

> 
> 
> Thanks,
> pq