Re: guix --container is RAM hungry

[Ricardo Wurmus]

raingloom@riseup.net writes:

> On 2024-03-21 22:44, Edouard Klein wrote:
>> Dear Guixers,
>> 
>> I'm a huge fan of guix --container, and I created a system to use those
>> by default for network services. But the VPS these services run on has
>> only 2GB of RAM, and I just realized that a container, by default,
>> requires at least 200MB.
>> 
>> Try it:
>> guix shell time which -- bash -c "$(which time) -v guix shell
>> --container"
>> 
>> Then Ctrl-D, and look for this line:
>>      Maximum resident set size (kbytes): 291300
>> 
>> 291MB of RAM to run bash.
>> 
>> 
>> By contrast, removing the --container option from above yields:
>>      Maximum resident set size (kbytes): 64496
>> 
>> 64MB, still a lot, but I can live with that.
[...]
> My first guess is that the Guile process is hanging around waiting for
> the process it launched, instead of exec-ing into it directly.

In (@@ (guix scripts environment) launch-environment) we use execlp;
launch-environment is used by both launch-environment/fork as well as
launch-environment/container.  There is, however, an awful lot of
forking going on.

launch-environment/container uses call-with-container, which ends in
using launch-environment.  call-with-container forks, and
launch-environment also forks.

The Guile process that was started when launching Guix probably doesn't
get replaced in this case, as raingloom guessed.

-- 
Ricardo