On Wed 18-03-20 21:05:17, Baoquan He wrote: > On 03/17/20 at 11:49am, David Hildenbrand wrote: > > Distributions nowadays use udev rules ([1] [2]) to specify if and > > how to online hotplugged memory. The rules seem to get more complex with > > many special cases. Due to the various special cases, > > CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE cannot be used. All memory hotplug > > is handled via udev rules. > > > > Everytime we hotplug memory, the udev rule will come to the same > > conclusion. Especially Hyper-V (but also soon virtio-mem) add a lot of > > memory in separate memory blocks and wait for memory to get onlined by user > > space before continuing to add more memory blocks (to not add memory faster > > than it is getting onlined). This of course slows down the whole memory > > hotplug process. > > > > To make the job of distributions easier and to avoid udev rules that get > > more and more complicated, let's extend the mechanism provided by > > - /sys/devices/system/memory/auto_online_blocks > > - "memhp_default_state=" on the kernel cmdline > > to be able to specify also "online_movable" as well as "online_kernel" > > This patch series looks good, thanks. Since Andrew has merged it to -mm again, > I won't add my Reviewed-by to bother. JFYI, Andrew usually adds R-b or A-b tags as they are posted. -- Michal Hocko SUSE Labs
