Date: Mon, 27 Jul 2020 02:09:21 +0200 From: Polytropon <freebsd@edvax.de> To: "Steve O'Hara-Smith" <steve@sohara.org> Cc: Valeri Galtsev <galtsev@kicp.uchicago.edu>, freebsd-questions@freebsd.org Subject: Re: Ask stupid questions and you'll get a stupid answers, was: Technological advantages over Linux Message-ID: <20200727020921.92e951f7.freebsd@edvax.de> In-Reply-To: <20200726213915.00772928e53bd4105872ee71@sohara.org> References: <CAEJNuHxC7i%2Bq7cq65=my6mJZDdiK4gpQsKjMU1nvsm=Ri4On%2Bg@mail.gmail.com> <ce61b5e9-b71c-e5b7-c64d-f79884c87435@watters.ws> <20200725152412.GJ92589@admin.sibptus.ru> <CAGBxaX=Ktr-pqtT8FU37ajkYonVLYT_WhSenn23Tj5b=i0d-8g@mail.gmail.com> <20200725162403.GA4721@admin.sibptus.ru> <CAGBxaXmBZcCWqAZFR9OSyRGrqGFU%2BqCAZ8CfOi=0oXAmf-2=tA@mail.gmail.com> <20200725182554.deffc63058a7c9f6d343ef06@sohara.org> <04df312d-9b2b-1873-2117-79a49e089bd9@kicp.uchicago.edu> <20200726063256.GA22924@admin.sibptus.ru> <20200726093909.ee5e14e643d31da4dad5c804@sohara.org> <20200726151835.GA35966@admin.sibptus.ru> <27ca8c6c-6b06-6ad4-7af0-2b88f51a3856@kicp.uchicago.edu> <20200726165212.a0ac28ce104b9dfd009cc4c5@sohara.org> <7290c25a-aaf3-b864-0ed8-ec9558777681@kicp.uchicago.edu> <20200726213915.00772928e53bd4105872ee71@sohara.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sun, 26 Jul 2020 21:39:15 +0100, Steve O'Hara-Smith wrote:
> On Sun, 26 Jul 2020 10:56:16 -0500
> Valeri Galtsev <galtsev@kicp.uchicago.edu> wrote:
>
> >
> >
> > On 7/26/20 10:52 AM, Steve O'Hara-Smith wrote:
> > > On Sun, 26 Jul 2020 10:39:16 -0500
> > > Valeri Galtsev <galtsev@kicp.uchicago.edu> wrote:
> > >
> > >> My understanding of Linux OOM killer lies along same lines though my
> > >> understanding is much more simplified: kill minimal number of processes
> > >> to recover maximum amount of resources.
> > >
> > > Not always the right thing to do though.
> > >
> > >> Another speculative way to say
> > >> it would be: process owning maximum amount of RAM that keeps allocating
> > >> more RAM is first candidate.
> > >
> > > What a pity if that is the heavy weight analytic program that
> > > has a run time of several hours/days and is the only thing that matters
> > > running on the system.
> > >
> >
> > And yes, I agreed with your sentiments (or judgement): killing a process
> > is a bad thing always. Agreed before writing any of my comments.
>
> The trouble is there really isn't anything else the OS can do
> because nobody ever thought to implement SIG_RELEASE_SOME_MEMORY_PLEASE
> which would probably be the ideal solution provided at least *some*
> programs responded to it.
As you mentioned, it depends on the problem programs ("apps") to
actually receive and act upon such a signal. "We don't need to
care for SIGMEM, because if _we_ need memore, we _need_ it, and
the fscking OS should pay attention to us and give us all that
memory!" ;-)
> Which leaves the only variable how to choose which process to kill
> and there are no general rules for a good choice.
The OS cannot guess what programs the user is interested in
keeping at a certain time, and what programs it could stop to
free resources, neither can it predict how programs will react
when some processes are killed from within a call hierarchy.
"If a subtask is killed, re-instantiate the task, but allocate
twice the memory it had before!" ;-)
So we're currently living with what is technically possible,
not with what we desire to happen...
--
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20200727020921.92e951f7.freebsd>