[PATCH 074/166] migrate: set PROT_NONE on the PTEs and let NUMA balancing

[Liu Jingqi]

Need to enable CONFIG_NUMA_BALANCING firstly.
Set PROT_NONE on the PTEs that map to the page,
and do the actual migration in the context of process which initiate migration.

Signed-off-by: Liu Jingqi <jingqi.liu@xxxxxxxxx>
Signed-off-by: Fengguang Wu <fengguang.wu@xxxxxxxxx>
---
 mm/migrate.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/mm/migrate.c b/mm/migrate.c
index b27a287081c2..d933f6966601 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1530,6 +1530,21 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr,
 	if (page_mapcount(page) > 1 && !migrate_all)
 		goto out_putpage;
 
+	if (flags & MPOL_MF_SW_YOUNG) {
+		unsigned long start, end;
+		unsigned long nr_pte_updates = 0;
+
+		start = max(addr, vma->vm_start);
+
+		/* TODO: if huge page  */
+		end = ALIGN(addr + (1 << PAGE_SHIFT), PAGE_SIZE);
+		end = min(end, vma->vm_end);
+		nr_pte_updates = change_prot_numa(vma, start, end);
+
+		err = 0;
+		goto out_putpage;
+	}
+
 	if (PageHuge(page)) {
 		if (PageHead(page)) {
 			/* Check if the page is software young. */
-- 
2.15.0


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Content-Disposition: attachment; filename="0075-migrate-consolidate-MPOL_MF_SW_YOUNG-behaviors.patch"