On Wed, Jan 15, 2020 at 04:33:14PM +0100, David Hildenbrand wrote:
> This is the backport of the following fixes for 4.19-stable:
>
> - a31b264c2b41 ("mm/memory_hotplug: make
> unregister_memory_block_under_nodes() never fail")
> -- Turned out to not only be a cleanup but also a fix
> - 2c91f8fc6c99 ("mm/memory_hotplug: fix try_offline_node()")
> -- Automatic stable backport failed due to missing dependencies.
> - feee6b298916 ("mm/memory_hotplug: shrink zones when offlining memory")
> -- Was marked as stable 5.0+ due to the backport complexity,, but it's also
> relevant for 4.19/4.14. As I have to backport quite some cleanups
> already ...
>
> To minimize manual code changes, I decided to pull in quite some cleanups.
> Still some manual code changes are necessary (indicated in the individual
> patches). Especially missing arm64 hot(un)plug, missing sub-section hotadd
> support, and missing unification of mm/hmm.c and kernel/memremap.c requires
> care.
>
> Due to:
> - 4e0d2e7ef14d ("mm, sparse: pass nid instead of pgdat to
> sparse_add_one_section()")
> I need:
> - afe9b36ca890 ("mm/memunmap: don't access uninitialized memmap in
> memunmap_pages()")
>
> Please note that:
> - 4c4b7f9ba948 ("mm/memory_hotplug: remove memory block devices
> before arch_remove_memory()")
> Makes big (e.g., 32TB) machines boot up slower (e.g., 2h vs 10m). There is
> a performance fix in linux-next, but it does not seem to classify as a
> fix for current RC / stable.
>
> I did quite some testing with hot(un)plug, onlining/offlining of memory
> blocks and memory-less/CPU-less NUMA nodes under x86_64 - the same set of
> tests I run against upstream on a fairly regular basis. I compile-tested
> on PowerPC. I did not test any ZONE_DEVICE/HMM thingies.
>
> Let's see what people think - it's a lot of patches. If we want this,
> then I can try to prepare a similar set for 4.4-stable.
What bug(s) are these trying to fix here?
And why would 4.9 and 4.4 care about them?
thanks,
greg k-h
