Re: [PATCH -v3 0/13] mm: make movable onlining suck less

[Dan Williams]

On Fri, Apr 21, 2017 at 5:05 AM, Michal Hocko <mhocko@xxxxxxxxxx> wrote:
> Hi,
> The last version of this series has been posted here [1]. It has seen
> some more testing (thanks to Reza Arbab and Igor Mammedov[2]), Jerome's
> and Vlastimil's review resulted in few fixes mostly folded in their
> respected patches.
> There are 4 more patches (patch 6+ in this series).  I have checked the
> most prominent pfn walkers to skip over offline holes and now and I feel
> more comfortable to have this merged. All the reported issues should be
> fixed
>
> There is still a lot of work on top - namely this implementation doesn't
> support reonlining to a different zone on the zones boundaries but I
> will do that in a separate series because this one is getting quite
> large already and it should work reasonably well now.
>
> Joonsoo had some worries about pfn_valid and suggested to change its
> semantic to return false on offline holes but I would be rally worried
> to change a established semantic used by a lot of code and so I have
> introuduced pfn_to_online_page helper instead. If this is seen as a
> controversial point I would rather drop pfn_to_online_page and related
> patches as they are not stictly necessary because the code would be
> similarly broken as now wrt. offline holes.
>
> This is a rebase on top of linux-next (next-20170418) and the full
> series is in git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git
> try attempts/rewrite-mem_hotplug branch.
>
[..]
> Any thoughts, complains, suggestions?
>
> As a bonus we will get a nice cleanup in the memory hotplug codebase.
>  arch/ia64/mm/init.c            |  11 +-
>  arch/powerpc/mm/mem.c          |  12 +-
>  arch/s390/mm/init.c            |  32 +--
>  arch/sh/mm/init.c              |  10 +-
>  arch/x86/mm/init_32.c          |   7 +-
>  arch/x86/mm/init_64.c          |  11 +-
>  drivers/base/memory.c          |  79 +++----
>  drivers/base/node.c            |  58 ++----
>  include/linux/memory_hotplug.h |  40 +++-
>  include/linux/mmzone.h         |  44 +++-
>  include/linux/node.h           |  35 +++-
>  kernel/memremap.c              |   6 +-
>  mm/compaction.c                |   5 +-
>  mm/memory_hotplug.c            | 455 ++++++++++++++---------------------------
>  mm/page_alloc.c                |  13 +-
>  mm/page_isolation.c            |  26 ++-
>  mm/sparse.c                    |  48 ++++-
>  17 files changed, 407 insertions(+), 485 deletions(-)
>
> Shortlog says:
> Michal Hocko (13):
>       mm: remove return value from init_currently_empty_zone
>       mm, memory_hotplug: use node instead of zone in can_online_high_movable
>       mm: drop page_initialized check from get_nid_for_pfn
>       mm, memory_hotplug: get rid of is_zone_device_section
>       mm, memory_hotplug: split up register_one_node
>       mm, memory_hotplug: consider offline memblocks removable
>       mm: consider zone which is not fully populated to have holes
>       mm, compaction: skip over holes in __reset_isolation_suitable
>       mm: __first_valid_page skip over offline pages
>       mm, memory_hotplug: do not associate hotadded memory to zones until online
>       mm, memory_hotplug: replace for_device by want_memblock in arch_add_memory
>       mm, memory_hotplug: fix the section mismatch warning
>       mm, memory_hotplug: remove unused cruft after memory hotplug rework
>
> [1] http://lkml.kernel.org/r/20170410110351.12215-1-mhocko@xxxxxxxxxx
> [2] http://lkml.kernel.org/r/20170410162749.7d7f31c1@xxxxxxxxxxxxxxxxxxx
>
>

The latest "attempts/rewrite-mem_hotplug" branch passes my regression
testing if I cherry-pick the following x86/mm fixes from mainline:

e6ab9c4d4377 x86/mm/64: Fix crash in remove_pagetable()
71389703839e mm, zone_device: Replace {get, put}_zone_device_page()
with a single reference to fix pmem crash

You can add:

Tested-by: Dan Williams <dan.j.williams@xxxxxxxxx>