On Mon, 3 Apr 2023, Lennart Poettering wrote:
> On Sa, 01.04.23 06:16, Michael Chapman (m...@very.puzzling.org) wrote:
>
> > > Well, in larger environments the goal is typically to saturate all
> > > hosts, but not overload them. i.e. maximizing your ROI. No need to
> > > fall from one extreme
On Sa, 01.04.23 06:16, Michael Chapman (m...@very.puzzling.org) wrote:
> > Well, in larger environments the goal is typically to saturate all
> > hosts, but not overload them. i.e. maximizing your ROI. No need to
> > fall from one extreme into the other. Today's Linux can actually
> > achieve
On Fr, 31.03.23 13:34, Christoph Anton Mitterer (cales...@scientia.org) wrote:
> Hey.
>
> Just for better understanding:
>
> AFAIU, the main idea of having swap despite enough memory was the
> following:
>
> Unless when processes explicitly release memory (or get stopped), the
> kernel can mostly
On Sat, 1 Apr 2023, Uoti Urpala wrote:
> On Sat, 2023-04-01 at 06:16 +1100, Michael Chapman wrote:
> > On Fri, 31 Mar 2023, Lennart Poettering wrote:
> > [...]
> > > Presumably your system mmaps ELF binaries, VM images, and similar
> > > stuff into memory. if you don't allow anonymous memory to
On Sat, 2023-04-01 at 06:16 +1100, Michael Chapman wrote:
> On Fri, 31 Mar 2023, Lennart Poettering wrote:
> [...]
> > Presumably your system mmaps ELF binaries, VM images, and similar
> > stuff into memory. if you don't allow anonymous memory to backed out
> > onto swap, then you basically
On Fri, 31 Mar 2023, Lennart Poettering wrote:
[...]
> Presumably your system mmaps ELF binaries, VM images, and similar
> stuff into memory. if you don't allow anonymous memory to backed out
> onto swap, then you basically telling the kernel "please page out
> my program code out instead". Which
On Fri, 2023-03-31 at 12:50 +0200, Lennart Poettering wrote:
> On Do, 30.03.23 13:16, Phillip Susi (ph...@thesusis.net) wrote:
>
> >
> > Lennart Poettering writes:
> >
> > > oomd/PSI looks at memory allocation latencies to determine memory
> > > pressure. Since you disallow anonymous memory to
On Fr, 31.03.23 21:54, Michael Chapman (m...@very.puzzling.org) wrote:
> > because otherwise you just remove the latencies from anonymous memory
> > but you amplify the latencies on file-backed memory. Which is overall
> > worse, not better.
>
> The host isn't doing much IO. Just a bit of logging
Hey.
Just for better understanding:
AFAIU, the main idea of having swap despite enough memory was the
following:
Unless when processes explicitly release memory (or get stopped), the
kernel can mostly reclaim only cached memory,... but if swap is
available it can also reclaim anonymous memory.
On Fri, 31 Mar 2023, Lennart Poettering wrote:
> On Fr, 31.03.23 07:57, Michael Chapman (m...@very.puzzling.org) wrote:
>
> > On Fri, 31 Mar 2023, Luca Boccassi wrote:
> > [...]
> > > No, it does not make "little difference", there are entire subsystems
> > > which are much worse off, if not
On Fri, 31 Mar 2023, Lennart Poettering wrote:
> On Fr, 31.03.23 18:24, Michael Chapman (m...@very.puzzling.org) wrote:
>
> > On Fri, 31 Mar 2023, Barry wrote:
> > [...]
> > > If you want to run in ram only then you must turn off the kernel
> > > overcommit.
> > > Have you done that? If not then
On Do, 30.03.23 13:16, Phillip Susi (ph...@thesusis.net) wrote:
>
> Lennart Poettering writes:
>
> > oomd/PSI looks at memory allocation latencies to determine memory
> > pressure. Since you disallow anonymous memory to be paged out and thus
> > increase IO on file backed memory you increase the
On Fr, 31.03.23 07:57, Michael Chapman (m...@very.puzzling.org) wrote:
> On Fri, 31 Mar 2023, Luca Boccassi wrote:
> [...]
> > No, it does not make "little difference", there are entire subsystems
> > which are much worse off, if not completely useless, without swap.
> > Post-cgroupsv2 memory
On Fr, 31.03.23 18:24, Michael Chapman (m...@very.puzzling.org) wrote:
> On Fri, 31 Mar 2023, Barry wrote:
> [...]
> > If you want to run in ram only then you must turn off the kernel overcommit.
> > Have you done that? If not then you risk processes getting SEGV signals.
>
> Seriously. It's
On Fri, 31 Mar 2023, Lennart Poettering wrote:
> On Do, 30.03.23 18:56, Michael Chapman (m...@very.puzzling.org) wrote:
>
> > On Thu, 30 Mar 2023, Lennart Poettering wrote:
> > > On Mi, 29.03.23 13:53, Christoph Anton Mitterer (cales...@scientia.org)
> > > wrote:
> > >
> > > > > > That's a bad
On Do, 30.03.23 18:56, Michael Chapman (m...@very.puzzling.org) wrote:
> On Thu, 30 Mar 2023, Lennart Poettering wrote:
> > On Mi, 29.03.23 13:53, Christoph Anton Mitterer (cales...@scientia.org)
> > wrote:
> >
> > > > > That's a bad idea btw. I'd advise you not to do that: on modern
> > > > >
On Do, 30.03.23 01:39, Christoph Anton Mitterer (cales...@scientia.org) wrote:
> Well that's clear, it's just that on my systems (both servers and
> workstations) I've never really run into the need to reclaim lots of
> anonymous memory.
It's the Linux kernel that reclaims memory for you. You
On Fri, 31 Mar 2023, Tomasz Torcz wrote:
> On Fri, Mar 31, 2023 at 06:24:09PM +1100, Michael Chapman wrote:
> > On Fri, 31 Mar 2023, Barry wrote:
> > [...]
> > > If you want to run in ram only then you must turn off the kernel
> > > overcommit.
> > > Have you done that? If not then you risk
On Fri, Mar 31, 2023 at 06:24:09PM +1100, Michael Chapman wrote:
> On Fri, 31 Mar 2023, Barry wrote:
> [...]
> > If you want to run in ram only then you must turn off the kernel overcommit.
> > Have you done that? If not then you risk processes getting SEGV signals.
>
> Seriously. It's almost as
On Fri, 31 Mar 2023, Barry wrote:
[...]
> If you want to run in ram only then you must turn off the kernel overcommit.
> Have you done that? If not then you risk processes getting SEGV signals.
Seriously. It's almost as if nobody here is actually reading anything of
what I've written!
> On 31 Mar 2023, at 00:51, Michael Chapman wrote:
>
> On Fri, 31 Mar 2023, Phillip Susi wrote:
>>
>> Michael Chapman writes:
>>
>>> What specifically is the difference between:
>>>
>>> * swap does not exist at all;
>>> * swap is full of data that will not be swapped in for weeks or
On Fri, 31 Mar 2023, Phillip Susi wrote:
>
> Michael Chapman writes:
>
> > What specifically is the difference between:
> >
> > * swap does not exist at all;
> > * swap is full of data that will not be swapped in for weeks or months;
>
> That's the wrong question.
Nevertheless it was the
Michael Chapman writes:
> What specifically is the difference between:
>
> * swap does not exist at all;
> * swap is full of data that will not be swapped in for weeks or months;
That's the wrong question. The question is, what is the difference
between having NO swap, and having some swap
On Fri, 31 Mar 2023, Luca Boccassi wrote:
[...]
> No, it does not make "little difference", there are entire subsystems
> which are much worse off, if not completely useless, without swap.
> Post-cgroupsv2 memory controller things are considerably different on
> this front, and old "common wisdom"
Lennart Poettering writes:
> oomd/PSI looks at memory allocation latencies to determine memory
> pressure. Since you disallow anonymous memory to be paged out and thus
> increase IO on file backed memory you increase the latencies
> unnecessarily, thus making oomd trigger earlier.
Did this
On Thu, 30 Mar 2023 at 11:09, Michael Chapman wrote:
>
> On Thu, 30 Mar 2023, Luca Boccassi wrote:
> > On Thu, 30 Mar 2023 at 10:15, Michael Chapman
> > wrote:
> > >
> > > On Thu, 30 Mar 2023, Lennart Poettering wrote:
> > > > On Mi, 29.03.23 13:53, Christoph Anton Mitterer
On Thu, 30 Mar 2023, Greg KH wrote:
> On Thu, Mar 30, 2023 at 09:09:19PM +1100, Michael Chapman wrote:
> > On Thu, 30 Mar 2023, Luca Boccassi wrote:
> > > On Thu, 30 Mar 2023 at 10:15, Michael Chapman
> > > wrote:
> > > >
> > > > On Thu, 30 Mar 2023, Lennart Poettering wrote:
> > > > > On Mi,
On Thu, Mar 30, 2023 at 09:09:19PM +1100, Michael Chapman wrote:
> On Thu, 30 Mar 2023, Luca Boccassi wrote:
> > On Thu, 30 Mar 2023 at 10:15, Michael Chapman
> > wrote:
> > >
> > > On Thu, 30 Mar 2023, Lennart Poettering wrote:
> > > > On Mi, 29.03.23 13:53, Christoph Anton Mitterer
On Thu, 30 Mar 2023, Luca Boccassi wrote:
> On Thu, 30 Mar 2023 at 10:15, Michael Chapman wrote:
> >
> > On Thu, 30 Mar 2023, Lennart Poettering wrote:
> > > On Mi, 29.03.23 13:53, Christoph Anton Mitterer (cales...@scientia.org)
> > > wrote:
> > >
> > > > > > That's a bad idea btw. I'd advise
On Thu, 30 Mar 2023 at 10:15, Michael Chapman wrote:
>
> On Thu, 30 Mar 2023, Lennart Poettering wrote:
> > On Mi, 29.03.23 13:53, Christoph Anton Mitterer (cales...@scientia.org)
> > wrote:
> >
> > > > > That's a bad idea btw. I'd advise you not to do that: on modern
> > > > > systems you want
On Thu, 30 Mar 2023, Lennart Poettering wrote:
> On Mi, 29.03.23 13:53, Christoph Anton Mitterer (cales...@scientia.org) wrote:
>
> > > > That's a bad idea btw. I'd advise you not to do that: on modern
> > > > systems you want swap, since it makes anonymous memory reclaimable.
> > > > I
> > > >
Hey Lennart.
On Wed, 2023-03-29 at 16:35 +0200, Lennart Poettering wrote:
> In almost all scenarios you want swap, regardless if little RAM or a
> lot. For specialist cases where you run everything from memory, and
> not even programs are backed by disk there might be exceptions.
Similar to the
On Mi, 29.03.23 14:07, Christoph Anton Mitterer (cales...@scientia.org) wrote:
> When I use
>systemd.log_level=debug systemd.log_target=console
> in the kernel parameters, and then do systemctl hibernate during the
> system I get:
> Mar 29 12:04:48 hbt systemd-logind[780]: Got message
On Mi, 29.03.23 13:53, Christoph Anton Mitterer (cales...@scientia.org) wrote:
> > > That's a bad idea btw. I'd advise you not to do that: on modern
> > > systems you want swap, since it makes anonymous memory reclaimable.
> > > I
> > > am not sure where you are getting this idea from that swap
When I use
systemd.log_level=debug systemd.log_target=console
in the kernel parameters, and then do systemctl hibernate during the
system I get:
Mar 29 12:04:48 hbt systemd-logind[780]: Got message type=method_call
sender=:1.9 destination=org.freedesktop.login1 path=/org/freedesktop/login1
Hey.
On Wed, 2023-03-29 at 10:20 +0200, Lennart Poettering wrote:
> > That's a bad idea btw. I'd advise you not to do that: on modern
> > systems you want swap, since it makes anonymous memory reclaimable.
> > I
> > am not sure where you are getting this idea from that swap was
> > bad.
Well I
On Mi, 29.03.23 04:43, Christoph Anton Mitterer (cales...@scientia.org) wrote:
Hi!
> I guess many people nowadays will run without any swap for the normal
> paging use, but only have it for hibernation (at least on laptops).
That's a bad idea btw. I'd advise you not to do that: on modern
Hey folks.
I guess many people nowadays will run without any swap for the normal
paging use, but only have it for hibernation (at least on laptops).
Since there's nothing yet like [0] I wanted to set up systemd to
automatically start/stop the swap right before/after hibernate/resume.
And I also
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