[RFC PATCH v1 2/4] mm/damon: Support for synchrounous huge pages collapse

[<gutierrez.asier@huawei-partners.com>]

From: Asier Gutierrez <gutierrez.asier@huawei-partners.com>

* Support for huge pages collapse, which will be used by
  dynamic_hugepages module.

* Include the new module for compilation

Signed-off-by: Asier Gutierrez <gutierrez.asier@huawei-partners.com>
Co-developed-by: Anatoly Stepanov <stepanov.anatoly@huawei.com>
---
 include/linux/damon.h | 1 +
 mm/damon/Kconfig      | 7 +++++++
 mm/damon/Makefile     | 1 +
 mm/damon/vaddr.c      | 3 +++
 4 files changed, 12 insertions(+)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 3813373a9200..de5a994f92c2 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -142,6 +142,7 @@ enum damos_action {
 	DAMOS_LRU_DEPRIO,
 	DAMOS_MIGRATE_HOT,
 	DAMOS_MIGRATE_COLD,
+	DAMOS_COLLAPSE,
 	DAMOS_STAT,		/* Do nothing but only record the stat */
 	NR_DAMOS_ACTIONS,
 };
diff --git a/mm/damon/Kconfig b/mm/damon/Kconfig
index 8c868f7035fc..2355aacb6d12 100644
--- a/mm/damon/Kconfig
+++ b/mm/damon/Kconfig
@@ -110,4 +110,11 @@ config DAMON_STAT_ENABLED_DEFAULT
 	  Whether to enable DAMON_STAT by default.  Users can disable it in
 	  boot or runtime using its 'enabled' parameter.
 
+config DAMON_HOT_HUGEPAGE
+	bool "Build DAMON-based collapse of hot regions (DAMON_HOT_HUGEPAGES)"
+	depends on DAMON_VADDR
+	help
+	 Collapse hot region into huge pages. Hot regions are determined by
+	 DAMON-based sampling
+
 endmenu
diff --git a/mm/damon/Makefile b/mm/damon/Makefile
index d8d6bf5f8bff..998bddc17819 100644
--- a/mm/damon/Makefile
+++ b/mm/damon/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_DAMON_SYSFS)	+= sysfs-common.o sysfs-schemes.o sysfs.o
 obj-$(CONFIG_DAMON_RECLAIM)	+= modules-common.o reclaim.o
 obj-$(CONFIG_DAMON_LRU_SORT)	+= modules-common.o lru_sort.o
 obj-$(CONFIG_DAMON_STAT)	+= modules-common.o stat.o
+obj-$(CONFIG_DAMON_HOT_HUGEPAGE)	+= modules-common.o dynamic_hugepages.o
diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c
index 23ed738a0bd6..4acbc1a6a5be 100644
--- a/mm/damon/vaddr.c
+++ b/mm/damon/vaddr.c
@@ -970,6 +970,9 @@ 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_MIGRATE_HOT:
 	case DAMOS_MIGRATE_COLD:
 		return damos_va_migrate(t, r, scheme, sz_filter_passed);
-- 
2.43.0