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From:   SeongJae Park <sj@kernel.org>
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     damon@lists.linux.dev, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, SeongJae Park <sj@kernel.org>
Subject: [RFC PATCH 02/11] mm/damon/paddr: support DAMOS filters
Date:   Thu, 24 Nov 2022 21:21:05 +0000
Message-Id: <20221124212114.136863-3-sj@kernel.org>
In-Reply-To: <20221124212114.136863-1-sj@kernel.org>
References: <20221124212114.136863-1-sj@kernel.org>
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Implement support of the DAMOS filters in the physical address space
monitoring operations set, for all DAMOS actions that it supports
including 'pageout', 'lru_prio', and 'lru_deprio'.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/paddr.c | 71 ++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 62 insertions(+), 9 deletions(-)

diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index e1a4315c4be6..ebd1905eed6f 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -202,7 +202,47 @@ static unsigned int damon_pa_check_accesses(struct damon_ctx *ctx)
 	return max_nr_accesses;
 }
 
-static unsigned long damon_pa_pageout(struct damon_region *r)
+static bool __damos_pa_filter_out(struct damos_filter *filter,
+		struct page *page)
+{
+	bool matched = false;
+	struct mem_cgroup *memcg;
+
+	switch (filter->type) {
+	case DAMOS_FILTER_TYPE_ANON:
+		matched = PageAnon(page);
+		break;
+	case DAMOS_FILTER_TYPE_MEMCG:
+		rcu_read_lock();
+		memcg = page_memcg_check(page);
+		if (!memcg)
+			matched = false;
+		else
+			matched = filter->memcg_id == mem_cgroup_id(memcg);
+		rcu_read_unlock();
+		break;
+	default:
+		break;
+	}
+
+	return matched == filter->matching;
+}
+
+/*
+ * damos_pa_filter_out - Return true if the page should be filtered out.
+ */
+static bool damos_pa_filter_out(struct damos *scheme, struct page *page)
+{
+	struct damos_filter *filter;
+
+	damos_for_each_filter(filter, scheme) {
+		if (__damos_pa_filter_out(filter, page))
+			return true;
+	}
+	return false;
+}
+
+static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s)
 {
 	unsigned long addr, applied;
 	LIST_HEAD(page_list);
@@ -213,6 +253,11 @@ static unsigned long damon_pa_pageout(struct damon_region *r)
 		if (!page)
 			continue;
 
+		if (damos_pa_filter_out(s, page)) {
+			put_page(page);
+			continue;
+		}
+
 		ClearPageReferenced(page);
 		test_and_clear_page_young(page);
 		if (isolate_lru_page(page)) {
@@ -232,7 +277,7 @@ static unsigned long damon_pa_pageout(struct damon_region *r)
 }
 
 static inline unsigned long damon_pa_mark_accessed_or_deactivate(
-		struct damon_region *r, bool mark_accessed)
+		struct damon_region *r, struct damos *s, bool mark_accessed)
 {
 	unsigned long addr, applied = 0;
 
@@ -241,6 +286,12 @@ static inline unsigned long damon_pa_mark_accessed_or_deactivate(
 
 		if (!page)
 			continue;
+
+		if (damos_pa_filter_out(s, page)) {
+			put_page(page);
+			continue;
+		}
+
 		if (mark_accessed)
 			mark_page_accessed(page);
 		else
@@ -251,14 +302,16 @@ static inline unsigned long damon_pa_mark_accessed_or_deactivate(
 	return applied * PAGE_SIZE;
 }
 
-static unsigned long damon_pa_mark_accessed(struct damon_region *r)
+static unsigned long damon_pa_mark_accessed(struct damon_region *r,
+	struct damos *s)
 {
-	return damon_pa_mark_accessed_or_deactivate(r, true);
+	return damon_pa_mark_accessed_or_deactivate(r, s, true);
 }
 
-static unsigned long damon_pa_deactivate_pages(struct damon_region *r)
+static unsigned long damon_pa_deactivate_pages(struct damon_region *r,
+	struct damos *s)
 {
-	return damon_pa_mark_accessed_or_deactivate(r, false);
+	return damon_pa_mark_accessed_or_deactivate(r, s, false);
 }
 
 static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx,
@@ -267,11 +320,11 @@ static unsigned long damon_pa_apply_scheme(struct damon_ctx *ctx,
 {
 	switch (scheme->action) {
 	case DAMOS_PAGEOUT:
-		return damon_pa_pageout(r);
+		return damon_pa_pageout(r, scheme);
 	case DAMOS_LRU_PRIO:
-		return damon_pa_mark_accessed(r);
+		return damon_pa_mark_accessed(r, scheme);
 	case DAMOS_LRU_DEPRIO:
-		return damon_pa_deactivate_pages(r);
+		return damon_pa_deactivate_pages(r, scheme);
 	case DAMOS_STAT:
 		break;
 	default:
-- 
2.25.1