On Fri 24-01-20 13:10:22, Fontenot, Nathan wrote: > It's been awhile since I've looked at the powerpc-utils drmgr command and > pseries DLPAR code but a quick scan makes and it appears that it hasn't changed > too much. Given that, some thoughts. > > The sysfs 'removable' file was a great help when memory DLPAR was driven > from userspace in the powerpc-utils drmgr command. Having this check did improve > performance though I can't point to any numbers. Do you still have an access to the HW to give it a try? > Currently, memory DLPAR is done completely in the kernel. The request is > initiated from drmgr writing to /sys/kernel/dlpar (for pHyp partitions) > or from a hotplug interrupt (for guests). I don't believe the 'removable' > sysfs file is used in either of these paths by drmgr. The only time it is > used is on older kernels that do not support in-kernel memory DLPAR. > > Given this, I don't think removing the 'removable' sysfs file would cause any > issues for the drmgr command. The only scenario I can think of is using an old > version of drmgr that does not support in-kernel memory DLPAR on a new kernel > where the 'removable' sysfs file has been removed. This doesn't seem likely > though and drmgr could be updated to detect this. Thanks for the information! -- Michal Hocko SUSE Labs
