Re: UVM behavior under memory pressure

[Frank Kardel <kardel%netbsd.org@localhost>]

This reminds me of a major cleanup Andrew Doran did in -current.

 PR kern/54209: NetBSD 8 large memory performance extremely low
 PR kern/54210: NetBSD-8 processes presumably not exiting
 PR kern/54727: writing a large file causes unreasonable system behaviour

The logic in -current has dramatically changed so that we didn't opt
for backporting that to -9 and -8.

Have you tried the with -current?

Best regards,
  Frank


On 04/01/21 21:03, Manuel Bouyer wrote:
> hello
> on a system running netbsd-9 from mid-august, I ended up in a state where
> the system has little free memory, no free swap and almost 40% of RAM used
> by the file cache:
>
> load averages:  9.00,  5.02,  2.86;               up 0+11:30:56        20:57:39
> 97 processes: 2 runnable, 91 sleeping, 1 stopped, 3 on CPU
> CPU states:  0.7% user,  0.0% nice, 96.5% system,  0.0% interrupt,  2.6% idle
> Memory: 4987M Act, 2436M Inact, 123M Wired, 198M Exec, 2918M File, 4216K Free
> Swap: 520M Total, 520M Used, 4K Free
>
>    PID USERNAME PRI NICE   SIZE   RES STATE      TIME   WCPU    CPU COMMAND
>      0 root       0    0     0K   30M CPU/3     11:27  0.00%   122% [system]
>   1009 bouyer    43    0  2978M  275M parked/0   9:32 27.78% 27.78% firefox68
>   1519 bouyer    26    0  2583M  141M RUN/0      0:37 20.90% 20.90% firefox68
>   1243 bouyer    25    0  2912M  350M RUN/2      2:56 60.96% 20.12% firefox68
>   7341 bouyer    26    0  3221M 2807M CPU/2      5:07 17.09% 17.09% openscad
>    729 bouyer    76    0   202M   39M select/3  26:03 16.65% 16.65% X
>
> Of course the system is very slow
> Shouldn't UVM choose, in this case, to reclaim pages from the file cache
> for the process data ?
> I'm using the default vm.* sysctl values.