On Thu, Apr 06, 2017 at 06:21:55PM +0200, Michal Hocko wrote: > On Thu 06-04-17 10:46:53, Reza Arbab wrote: > > On Thu, Apr 06, 2017 at 05:41:28PM +0200, Michal Hocko wrote: > > >On Thu 06-04-17 10:24:49, Reza Arbab wrote: > > >>On Thu, Apr 06, 2017 at 03:08:46PM +0200, Michal Hocko wrote: > > >>>OK, so after recent change mostly driven by testing from Reza Arbab > > >>>(thanks again) I believe I am getting to a working state finally. All I > > >>>currently have is > > >>>in git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git tree > > >>>attempts/rewrite-mem_hotplug-WIP branch. I will highly appreciate more > > >>>testing of course and if there are no new issues found I will repost the > > >>>series for the review. > > >> > > >>Looking good! I can do my add/remove/repeat test and things seem fine. > > >> > > >>One thing--starting on the second iteration, I am seeing the WARN in > > >>free_area_init_node(); > > >> > > >>add_memory > > >> add_memory_resource > > >> hotadd_new_pgdat > > >> free_area_init_node > > >> WARN_ON(pgdat->nr_zones || pgdat->kswapd_classzone_idx); > > > > > >Have you tested with my attempts/rewrite-mem_hotplug-WIP mentioned > > >elsewhere? Because I suspect that "mm: get rid of zone_is_initialized" > > >might cause this. > > > > This was my first time using your git branch instead of applying the patches > > from this thread to v4.11-rc5 myself. > > OK, so this looks like another thing to resolve. I have seen this > warning as well but I didn't consider it relevant because I had to tweak > the code make the node go offline (removed check_and_unmap_cpu_on_node > from try_offline_node) so I thought it was a fallout from there. > > But let's have a look. hotadd_new_pgdat does for an existing pgdat > /* Reset the nr_zones, order and classzone_idx before reuse */ > pgdat->nr_zones = 0; > pgdat->kswapd_order = 0; > pgdat->kswapd_classzone_idx = MAX_NR_ZONES; > > so free_area_init_node absolutely has to hit this warning. This is not > in the Linus tree because it is still in Andrew's mmotm coming from > http://www.ozlabs.org/~akpm/mmotm/broken-out/mm-vmscan-prevent-kswapd-sleeping-prematurely-due-to-mismatched-classzone_idx.patch > > So yay, finally that doesn't come from me. Mel, I guess that either > hotadd_new_pgdat should keep its kswapd_classzone_idx = 0 or the warning > should be updated. > Almost certainly the case that the warning should be updated. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
