kswapd0 freezing the system for a few seconds once a while
by Lockywolf from LinuxQuestions.org on (#5BDHH)
Hello, everyone.
This started happening since I moved to a different laptop with the same Slackware on an SSD. The hardware configuration is very different from what I have been using before (/home is on and SSD now, intel video card).
I still have a swap partition on sdb2.
So what started happening on the new laptop: the system periodically freezes for a few seconds, with iotop showing high IO (>95%); READ and WRITE stay small, an order of kilobytes. This happens regardless of memory consumption, it may be that there is still >4Gb memory free.
Freezes disappear if swap is turned off, but I do use swap extensively, both for running a lot of software at the boot time (restoring from swap is faster than launching) and for hibernation.
How to debug this?
UPDATE:
I found part of the cause. My /tmp is on tmpfs, and the FS was constantly swapping out.
The problem is that it is slowing the system! weird. I'd expect the least used files in tmpfs to be swapped out.
This started happening since I moved to a different laptop with the same Slackware on an SSD. The hardware configuration is very different from what I have been using before (/home is on and SSD now, intel video card).
I still have a swap partition on sdb2.
So what started happening on the new laptop: the system periodically freezes for a few seconds, with iotop showing high IO (>95%); READ and WRITE stay small, an order of kilobytes. This happens regardless of memory consumption, it may be that there is still >4Gb memory free.
Freezes disappear if swap is turned off, but I do use swap extensively, both for running a lot of software at the boot time (restoring from swap is faster than launching) and for hibernation.
How to debug this?
UPDATE:
I found part of the cause. My /tmp is on tmpfs, and the FS was constantly swapping out.
The problem is that it is slowing the system! weird. I'd expect the least used files in tmpfs to be swapped out.