On Sun, Nov 29, 2020 at 11:56:55AM +0100, Mike Galbraith wrote: > On Sun, 2020-11-29 at 10:21 +0100, Mike Galbraith wrote: > > On Sun, 2020-11-29 at 08:48 +0100, Mike Galbraith wrote: > > > On Sun, 2020-11-29 at 07:41 +0100, Mike Galbraith wrote: > > > > On Sat, 2020-11-28 at 15:27 +0100, Oleksandr Natalenko wrote: > > > > > > > > > > > > Shouldn't the list manipulation be protected with > > > > > > > local_lock+this_cpu_ptr instead of get_cpu_ptr+spin_lock? > > > > > > > > > > Totally untested: > > > > > > > > Hrm, the thing doesn't seem to care deeply about preemption being > > > > disabled, so adding another lock may be overkill. It looks like you > > > > could get the job done via migrate_disable()+this_cpu_ptr(). > > > > > > There is however an ever so tiny chance that I'm wrong about that :) > > > > Or not, your local_lock+this_cpu_ptr version exploded too. > > > > Perhaps there's a bit of non-rt related racy racy going on in zswap > > thingy that makes swap an even less wonderful idea for RT than usual. > > Raciness seems to be restricted to pool compressor. "zbud" seems to be > solid, virgin "zsmalloc" explodes, as does "z3fold" regardless which of > us puts his grubby fingerprints on it. > > Exploding compressors survived zero runs of runltp -f mm, I declared > zbud to be at least kinda sorta stable after box survived five runs. Ummm so do compressors explode under non-rt kernel in your tests as well, or it is just -rt that triggers this? I've never seen that on both -rt and non-rt, thus asking. -- Oleksandr Natalenko (post-factum)
