On Sun, 27 Jan 2019 17:00:27 +0100, Pavel Machek said: > > > I've noticed this as well on earlier kernels (next-20181224 to 20190115) > > > Some more info: > > > 1) echo 3 > /proc/sys/vm/drop_caches unwedges kcompactd in 1-3 seconds. > > This aspect is curious as it indicates that kcompactd could potentially > > be infinite looping but it's not something I've experienced myself. By > > any chance is there a preditable reproduction case for this? > > I seen it exactly once, so not sure how reproducible this is. x86-32 > machine, running chromium browser, so yes, there was some swapping > involved.
I don't have a surefire replicator, but my laptop (x86_64, so it's not a 32-bit only issue) triggers it fairly often, up to multiple times a day. Doesn't seem to be just the Chrome browser that triggers it - usually I'm doing other stuff as well, like a compile or similar. The fact that 'drop_caches' clears it makes me wonder if we're hitting a corner case where cache data isn't being automatically cleared and clogging something up. Any particular diagnostic info you want me to get next time it hits? (Am currently on next-20190125, if that matters).
