Zaz's questions

Most of the time when my computer starts to need swap, I see a massive spike in CPU usage (kswapd0 is consistently using 99%-100% CPU). According to top, the time is spent in sy (system/kernel) not wa (IO wait).

I am running Linux 4.0.4-2-ARCH on a C720 with 2GB RAM, and 6GB swap on an SSD.

I seem to have this problem with or without discard pages (TRIM) turned on.

Are there any setting I should inspect or tweak to see if I can fix this?

Is there any way to debug the problem? Something like strace for kernel threads?

Running with default Arch Linux settings:

/proc/sys/vm/swappiness = 60
/proc/sys/vm/vfs_cache_pressure = 100
/sys/kernel/mm/transparent_hugepage/enabled = [always] madvise never

I'm running a local test-server (on Ubuntu 10.04), but for some reason I don't seem to be seeing my custom 403/404 error messages. Here's some command output:

[ /var/www ] # ls -al:

drwxr-xr-x  5 www-data www-data 4096 2010-07-31 18:40 .
drwxr-xr-x 16 root     root     4096 2010-05-14 19:56 ..
-rwxr-xr-x  1 www-data www-data  493 2010-07-31 18:32 403.html
-rwxr-xr-x  1 www-data www-data  493 2010-07-31 18:10 404.html
-rwxr-xr-x  1 www-data www-data   56 2010-07-31 18:25 .htaccess

[ /var/www ] # cat .htaccess:

ErrorDocument 404 /404.html
ErrorDocument 403 /403.html

I'm completely stumped - can't find any info through Google either.