From: xu xin <xu.xin16@zte.com.cn>

There are two performance optimization patches for rmap_walk_ksm.

The patch [1/2] move the initializaion of addr from the position inside
loop to the position before the loop, since the variable will not change
in the loop.

The patch [2/2] optimize rmap_walk_ksm by passing a suitable page offset
range to the anon_vma_interval_tree_foreach loop to reduce ineffective
checks.

The metric performance and reproducer can be found at patch[2/2].

Changes in v3:
- Fix some typos in commit description
- Replace "pgoff_start" and 'pgoff_end' by 'pgoff'.

Changes in v2:
- Use const variable to initialize 'addr'  "pgoff_start" and 'pgoff_end'
- Let pgoff_end = pgoff_start, since KSM folios are always order-0 (Suggested by David)

xu xin (2):
  ksm: Initialize the addr only once in rmap_walk_ksm
  ksm: Optimize rmap_walk_ksm by passing a suitable address range

 mm/ksm.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

-- 
2.25.1