Comment # 4 on bug 1129214 from Michal Hocko

(In reply to Christian Wittmer from comment #3)
> (In reply to Michal Hocko from comment #2)
> > These all seem to be temporary allocation stalls 3 hitting one window Mar 8
> > and one mar 13. One hitting xfs, 2 skb and one vfs allocation paths. So
> > nothing really systematic. Checking the free memory proves that the memory
> > was mostly used.
> > 
> > I am strongly suspecting that some part of the memory reclaim (shrinkers
> > probably) took excessive amount of time to make a forward progress. We would
> > need vmsacan tracepoints data to know better though.
> 
> How can I provide such info about 'vmsacan tracepoints data' ?

There are two ways. You can either mount tracefs and enable
$TRACEFS_MNT/events/vmscan/{mm_vmscan_direct_reclaim_begin,mm_vmscan_direct_reclaim_end,mm_shrink_slab_start,mm_shrink_slab_end}
and read the output from $TRACE_MNT/trace_pipe or use trace-cmd to do the same.


Btw. is this reproducible?