[PATCH] mm/damon: add MADV_COLLAPSE support in damos_action

[Xin Hao <xhao@linux.alibaba.com>]

MADV_COLLAPSE has large different with MDVA_HUGE in dealing with huge
pages, it doesn't need to rely on 'khugepage' thread to create THP.
So combining with it will give damon users more options.

Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
---
 include/linux/damon.h | 1 +
 mm/damon/vaddr.c      | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 016b6c9c03d6..c44f9410d997 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -97,6 +97,7 @@ enum damos_action {
 	DAMOS_PAGEOUT,
 	DAMOS_HUGEPAGE,
 	DAMOS_NOHUGEPAGE,
+	DAMOS_COLLAPSE,
 	DAMOS_LRU_PRIO,
 	DAMOS_LRU_DEPRIO,
 	DAMOS_STAT,		/* Do nothing but only record the stat */
diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index c2c08c1b316b..58c0d068563d 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -655,6 +655,9 @@ static unsigned long damon_va_apply_scheme(struct damon_ctx *ctx,
 	case DAMOS_NOHUGEPAGE:
 		madv_action = MADV_NOHUGEPAGE;
 		break;
+	case DAMOS_COLLAPSE:
+		madv_action = MADV_COLLAPSE;
+		break;
 	case DAMOS_STAT:
 		return 0;
 	default:
-- 
2.31.0