mhocko@xxxxxxxxxx sed in <20200217103335.GI31531@xxxxxxxxxxxxxx> >> On Fri 14-02-20 23:26:29, kkabe@xxxxxxxxxxx wrote: >> [...] >> > [root@localhost ~]# [ 302.391125] hv_balloon: Max. dynamic memory size: 1048576 MB >> >> Is this saying that the system might hotplug up to 1TB of memory on this >> 32b system? Probably. Hypervisor API uses 64-bit values, so that's why I added add_memory() printk to see if it's overflowing 4GB. I guessed drivers/hv/hv_balloon.c:hv_mem_hot_add() needs a check to not hot-add over 4GB memory on non-PAE systems and so on, but that's another story. >> Btw. the hotplug support on highmem systems is quite likely to be broken >> and/or full of corner cases. I seriously doubt this is something anybody >> should be running in production without a _lot_ of work. >> >> Is there any real usecase to run HyperV hotplug on 32b system? >> -- >> Michal Hocko >> SUSE Labs
