On Tue, Jan 29, 2019 at 11:29:37PM -0500, valdis.kletni...@vt.edu wrote: > On Tue, 29 Jan 2019 20:06:39 -0500, valdis.kletni...@vt.edu said: > > On Mon, 28 Jan 2019 10:16:27 +0100, Jan Kara said: > > > > > So my buffer_migrate_page_norefs() is certainly buggy in its current > > > incarnation (as a result block device page cache is not migratable at > > > all). > > > I've sent Andrew a patch over week ago but so far it got ignored. The > > > patch > > > is attached, can you give it a try whether it changes something for you? > > > Thanks! > > > > Been running with the patch for about 24 hours, haven't seen kcompactd > > misbehave. I even fired up a Chrome with a lot of tabs open, a Firefox, > > and a > > kernel build, intentionally drove the system into swapping, and kcompactd > > didn't make it into the top 10 on 'top'. > > > > I'm willing to say put a "tested-by:" on that one, it looks fixed from > > here. > > If there's any remaining bugs, they're ones I can't seem to trigger... > > Spoke too soon. Sitting here not stressing the laptop at all, plenty of free > memory, and ka-blam. > > Will keep my eyes open and do the data gathering Mel Gorban wanted - I > discovered > too late that trace-cmd wasn't installed, and things broke free by themselves > (probably > not coincidence that I launched a terminal window and then it cleared....) >
That's unfortunate. I also note that linux-next still has not been updated with the latest version of the compaction series. Nevertheless, it might be helpful to get the output of grep -r . /sys/kernel/mm/transparent_hugepage/* and the trace when the system is in normal use but kcompactd has not pegged at 100%. At minimum, I'd like to see what the sources of high-order allocations are and the likely causes of wakeups of kcompactd in case there are any hints there. Your Kconfig is also potentially useful. Thanks. -- Mel Gorman SUSE Labs
