[PATCH v7 42/61] mm: Convert khugepaged_scan_shmem to XArray

From: Matthew Wilcox
Date: Mon Feb 19 2018 - 14:52:27 EST


From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>

Slightly shorter and easier to read code.

Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
---
mm/khugepaged.c | 17 +++++------------
1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index a1b1a714aff9..5c96452090ec 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1533,8 +1533,7 @@ static void khugepaged_scan_shmem(struct mm_struct *mm,
pgoff_t start, struct page **hpage)
{
struct page *page = NULL;
- struct radix_tree_iter iter;
- void **slot;
+ XA_STATE(xas, &mapping->pages, start);
int present, swap;
int node = NUMA_NO_NODE;
int result = SCAN_SUCCEED;
@@ -1543,17 +1542,11 @@ static void khugepaged_scan_shmem(struct mm_struct *mm,
swap = 0;
memset(khugepaged_node_load, 0, sizeof(khugepaged_node_load));
rcu_read_lock();
- radix_tree_for_each_slot(slot, &mapping->pages, &iter, start) {
- if (iter.index >= start + HPAGE_PMD_NR)
- break;
-
- page = radix_tree_deref_slot(slot);
- if (radix_tree_deref_retry(page)) {
- slot = radix_tree_iter_retry(&iter);
+ xas_for_each(&xas, page, start + HPAGE_PMD_NR - 1) {
+ if (xas_retry(&xas, page))
continue;
- }

- if (radix_tree_exception(page)) {
+ if (xa_is_value(page)) {
if (++swap > khugepaged_max_ptes_swap) {
result = SCAN_EXCEED_SWAP_PTE;
break;
@@ -1592,7 +1585,7 @@ static void khugepaged_scan_shmem(struct mm_struct *mm,
present++;

if (need_resched()) {
- slot = radix_tree_iter_resume(slot, &iter);
+ xas_pause(&xas);
cond_resched_rcu();
}
}
--
2.16.1