mm: vmalloc: remove global vmap_area_root rb-tree

Store allocated objects in a separate nodes.  A va->va_start address is
converted into a correct node where it should be placed and resided.  An
addr_to_node() function is used to do a proper address conversion to
determine a node that contains a VA.

Such approach balances VAs across nodes as a result an access becomes
scalable.  Number of nodes in a system depends on number of CPUs.

Please note:

1. As of now allocated VAs are bound to a node-0. It means the
   patch does not give any difference comparing with a current
   behavior;

2. The global vmap_area_lock, vmap_area_root are removed as there
   is no need in it anymore. The vmap_area_list is still kept and
   is _empty_. It is exported for a kexec only;

3. The vmallocinfo and vread() have to be reworked to be able to
   handle multiple nodes.

[[email protected]: mark vmap_init_free_space() with __init tag]
  Link: https://lkml.kernel.org/r/[email protected]
[[email protected]: fix a wrong value passed to __find_vmap_area()]
  Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Uladzislau Rezki (Sony) <[email protected]>
Reviewed-by: Baoquan He <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Anshuman Khandual <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Joel Fernandes (Google) <[email protected]>
Cc: Kazuhito Hagio <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Oleksiy Avramchenko <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions