[RFC v10 12/13] mm/damon/paddr: Separate commonly usable functions

[SeongJae Park <sjpark@amazon.com>]

From: SeongJae Park <sjpark@amazon.de>

This commit moves functions in the default physical address space
monitoring primitives that commonly usable from other use cases like
page granularity idleness monitoring to prmtv-common.

Signed-off-by: SeongJae Park <sjpark@amazon.de>
---
 mm/damon/paddr.c        | 122 ----------------------------------------
 mm/damon/prmtv-common.c | 122 ++++++++++++++++++++++++++++++++++++++++
 mm/damon/prmtv-common.h |   4 ++
 3 files changed, 126 insertions(+), 122 deletions(-)

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index b120f672cc57..143ddc0e5917 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -19,69 +19,6 @@
  * of the primitives.
  */
 
-/*
- * Get a page by pfn if it is in the LRU list.  Otherwise, returns NULL.
- *
- * The body of this function is stollen from the 'page_idle_get_page()'.  We
- * steal rather than reuse it because the code is quite simple.
- */
-static struct page *damon_pa_get_page(unsigned long pfn)
-{
-	struct page *page = pfn_to_online_page(pfn);
-	pg_data_t *pgdat;
-
-	if (!page || !PageLRU(page) ||
-	    !get_page_unless_zero(page))
-		return NULL;
-
-	pgdat = page_pgdat(page);
-	spin_lock_irq(&pgdat->lru_lock);
-	if (unlikely(!PageLRU(page))) {
-		put_page(page);
-		page = NULL;
-	}
-	spin_unlock_irq(&pgdat->lru_lock);
-	return page;
-}
-
-static bool __damon_pa_mkold(struct page *page, struct vm_area_struct *vma,
-		unsigned long addr, void *arg)
-{
-	damon_va_mkold(vma->vm_mm, addr);
-	return true;
-}
-
-static void damon_pa_mkold(unsigned long paddr)
-{
-	struct page *page = damon_pa_get_page(PHYS_PFN(paddr));
-	struct rmap_walk_control rwc = {
-		.rmap_one = __damon_pa_mkold,
-		.anon_lock = page_lock_anon_vma_read,
-	};
-	bool need_lock;
-
-	if (!page)
-		return;
-
-	if (!page_mapped(page) || !page_rmapping(page)) {
-		set_page_idle(page);
-		put_page(page);
-		return;
-	}
-
-	need_lock = !PageAnon(page) || PageKsm(page);
-	if (need_lock && !trylock_page(page)) {
-		put_page(page);
-		return;
-	}
-
-	rmap_walk(page, &rwc);
-
-	if (need_lock)
-		unlock_page(page);
-	put_page(page);
-}
-
 static void __damon_pa_prepare_access_check(struct damon_ctx *ctx,
 					    struct damon_region *r)
 {
@@ -101,65 +38,6 @@ void damon_pa_prepare_access_checks(struct damon_ctx *ctx)
 	}
 }
 
-struct damon_pa_access_chk_result {
-	unsigned long page_sz;
-	bool accessed;
-};
-
-static bool damon_pa_accessed(struct page *page, struct vm_area_struct *vma,
-		unsigned long addr, void *arg)
-{
-	struct damon_pa_access_chk_result *result = arg;
-
-	result->accessed = damon_va_young(vma->vm_mm, addr, &result->page_sz);
-
-	/* If accessed, stop walking */
-	return !result->accessed;
-}
-
-static bool damon_pa_young(unsigned long paddr, unsigned long *page_sz)
-{
-	struct page *page = damon_pa_get_page(PHYS_PFN(paddr));
-	struct damon_pa_access_chk_result result = {
-		.page_sz = PAGE_SIZE,
-		.accessed = false,
-	};
-	struct rmap_walk_control rwc = {
-		.arg = &result,
-		.rmap_one = damon_pa_accessed,
-		.anon_lock = page_lock_anon_vma_read,
-	};
-	bool need_lock;
-
-	if (!page)
-		return false;
-
-	if (!page_mapped(page) || !page_rmapping(page)) {
-		if (page_is_idle(page))
-			result.accessed = false;
-		else
-			result.accessed = true;
-		put_page(page);
-		goto out;
-	}
-
-	need_lock = !PageAnon(page) || PageKsm(page);
-	if (need_lock && !trylock_page(page)) {
-		put_page(page);
-		return NULL;
-	}
-
-	rmap_walk(page, &rwc);
-
-	if (need_lock)
-		unlock_page(page);
-	put_page(page);
-
-out:
-	*page_sz = result.page_sz;
-	return result.accessed;
-}
-
 /*
  * Check whether the region was accessed after the last preparation
  *
diff --git a/mm/damon/prmtv-common.c b/mm/damon/prmtv-common.c
index 6cdb96cbc9ef..6c2e760e086c 100644
--- a/mm/damon/prmtv-common.c
+++ b/mm/damon/prmtv-common.c
@@ -102,3 +102,125 @@ bool damon_va_young(struct mm_struct *mm, unsigned long addr,
 
 	return young;
 }
+
+/*
+ * Get a page by pfn if it is in the LRU list.  Otherwise, returns NULL.
+ *
+ * The body of this function is stollen from the 'page_idle_get_page()'.  We
+ * steal rather than reuse it because the code is quite simple.
+ */
+static struct page *damon_pa_get_page(unsigned long pfn)
+{
+	struct page *page = pfn_to_online_page(pfn);
+	pg_data_t *pgdat;
+
+	if (!page || !PageLRU(page) ||
+	    !get_page_unless_zero(page))
+		return NULL;
+
+	pgdat = page_pgdat(page);
+	spin_lock_irq(&pgdat->lru_lock);
+	if (unlikely(!PageLRU(page))) {
+		put_page(page);
+		page = NULL;
+	}
+	spin_unlock_irq(&pgdat->lru_lock);
+	return page;
+}
+
+static bool __damon_pa_mkold(struct page *page, struct vm_area_struct *vma,
+		unsigned long addr, void *arg)
+{
+	damon_va_mkold(vma->vm_mm, addr);
+	return true;
+}
+
+void damon_pa_mkold(unsigned long paddr)
+{
+	struct page *page = damon_pa_get_page(PHYS_PFN(paddr));
+	struct rmap_walk_control rwc = {
+		.rmap_one = __damon_pa_mkold,
+		.anon_lock = page_lock_anon_vma_read,
+	};
+	bool need_lock;
+
+	if (!page)
+		return;
+
+	if (!page_mapped(page) || !page_rmapping(page)) {
+		set_page_idle(page);
+		put_page(page);
+		return;
+	}
+
+	need_lock = !PageAnon(page) || PageKsm(page);
+	if (need_lock && !trylock_page(page)) {
+		put_page(page);
+		return;
+	}
+
+	rmap_walk(page, &rwc);
+
+	if (need_lock)
+		unlock_page(page);
+	put_page(page);
+}
+
+struct damon_pa_access_chk_result {
+	unsigned long page_sz;
+	bool accessed;
+};
+
+static bool damon_pa_accessed(struct page *page, struct vm_area_struct *vma,
+		unsigned long addr, void *arg)
+{
+	struct damon_pa_access_chk_result *result = arg;
+
+	result->accessed = damon_va_young(vma->vm_mm, addr, &result->page_sz);
+
+	/* If accessed, stop walking */
+	return !result->accessed;
+}
+
+bool damon_pa_young(unsigned long paddr, unsigned long *page_sz)
+{
+	struct page *page = damon_pa_get_page(PHYS_PFN(paddr));
+	struct damon_pa_access_chk_result result = {
+		.page_sz = PAGE_SIZE,
+		.accessed = false,
+	};
+	struct rmap_walk_control rwc = {
+		.arg = &result,
+		.rmap_one = damon_pa_accessed,
+		.anon_lock = page_lock_anon_vma_read,
+	};
+	bool need_lock;
+
+	if (!page)
+		return false;
+
+	if (!page_mapped(page) || !page_rmapping(page)) {
+		if (page_is_idle(page))
+			result.accessed = false;
+		else
+			result.accessed = true;
+		put_page(page);
+		goto out;
+	}
+
+	need_lock = !PageAnon(page) || PageKsm(page);
+	if (need_lock && !trylock_page(page)) {
+		put_page(page);
+		return NULL;
+	}
+
+	rmap_walk(page, &rwc);
+
+	if (need_lock)
+		unlock_page(page);
+	put_page(page);
+
+out:
+	*page_sz = result.page_sz;
+	return result.accessed;
+}
diff --git a/mm/damon/prmtv-common.h b/mm/damon/prmtv-common.h
index a66a6139b4fc..fbe9452bd040 100644
--- a/mm/damon/prmtv-common.h
+++ b/mm/damon/prmtv-common.h
@@ -10,6 +10,7 @@
 #include <linux/mmu_notifier.h>
 #include <linux/page_idle.h>
 #include <linux/random.h>
+#include <linux/rmap.h>
 #include <linux/sched/mm.h>
 #include <linux/slab.h>
 
@@ -19,3 +20,6 @@
 void damon_va_mkold(struct mm_struct *mm, unsigned long addr);
 bool damon_va_young(struct mm_struct *mm, unsigned long addr,
 			unsigned long *page_sz);
+
+void damon_pa_mkold(unsigned long paddr);
+bool damon_pa_young(unsigned long paddr, unsigned long *page_sz);
-- 
2.17.1