On Mon, Sep 16, 2019 at 11:17:37AM +0530, Anshuman Khandual wrote: > In add_memory_resource() the memory range to be hot added first gets into > the memblock via memblock_add() before arch_add_memory() is called on it. > Reverse sequence should be followed during memory hot removal which already > is being followed in add_memory_resource() error path. This now ensures > required re-order between memblock_[free|remove]() and arch_remove_memory() > during memory hot-remove. > > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: Oscar Salvador <osalvador@xxxxxxx> > Cc: Michal Hocko <mhocko@xxxxxxxx> > Cc: David Hildenbrand <david@xxxxxxxxxx> > Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> > Cc: Dan Williams <dan.j.williams@xxxxxxxxx> > Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> > --- > Original patch https://lkml.org/lkml/2019/9/3/327 > > Memory hot remove now works on arm64 without this because a recent commit > 60bb462fc7ad ("drivers/base/node.c: simplify unregister_memory_block_under_nodes()"). > > David mentioned that re-ordering should still make sense for consistency > purpose (removing stuff in the reverse order they were added). This patch > is now detached from arm64 hot-remove series. > > https://lkml.org/lkml/2019/9/3/326 > > mm/memory_hotplug.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index c73f09913165..355c466e0621 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -1770,13 +1770,13 @@ static int __ref try_remove_memory(int nid, u64 start, u64 size) > > /* remove memmap entry */ > firmware_map_remove(start, start + size, "System RAM"); > - memblock_free(start, size); > - memblock_remove(start, size); > > /* remove memory block devices before removing memory */ > remove_memory_block_devices(start, size); > > arch_remove_memory(nid, start, size, NULL); > + memblock_free(start, size); I don't see memblock_reserve() anywhere in memory_hotplug.c, so the memblock_free() call here seems superfluous. I think it can be simply dropped. > + memblock_remove(start, size); > __release_memory_resource(start, size); > > try_offline_node(nid); > -- > 2.20.1 > > -- Sincerely yours, Mike.
