hugetlb: parallelize 1G hugetlb initialization

Optimizing the initialization speed of 1G huge pages through
parallelization.

1G hugetlbs are allocated from bootmem, a process that is already very
fast and does not currently require optimization.  Therefore, we focus on
parallelizing only the initialization phase in `gather_bootmem_prealloc`.

Here are some test results:
      test case       no patch(ms)   patched(ms)   saved
 ------------------- -------------- ------------- --------
  256c2T(4 node) 1G           4745          2024   57.34%
  128c1T(2 node) 1G           3358          1712   49.02%
     12T         1G          77000         18300   76.23%

[[email protected]: s/initialied/initialized/, per Alexey]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Gang Li <[email protected]>
Tested-by: David Rientjes <[email protected]>
Reviewed-by: Muchun Song <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Daniel Jordan <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Jane Chu <[email protected]>
Cc: Mike Kravetz <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Steffen Klassert <[email protected]>
Cc: Tim Chen <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions