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Sender: "yuzhao via sendgmr" <yuzhao@yuzhao.bld.corp.google.com>
Date:   Fri, 22 Jan 2021 15:05:53 -0700
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Message-Id: <20210122220600.906146-4-yuzhao@google.com>
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References: <20210122220600.906146-1-yuzhao@google.com>
Subject: [PATCH v2 03/10] mm: don't pass "enum lru_list" to lru list addition functions
From:   Yu Zhao <yuzhao@google.com>
To:     Andrew Morton <akpm@linux-foundation.org>,
        Hugh Dickins <hughd@google.com>,
        Alex Shi <alex.shi@linux.alibaba.com>
Cc:     Michal Hocko <mhocko@kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Roman Gushchin <guro@fb.com>, Vlastimil Babka <vbabka@suse.cz>,
        Matthew Wilcox <willy@infradead.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Yu Zhao <yuzhao@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

The "enum lru_list" parameter to add_page_to_lru_list() and
add_page_to_lru_list_tail() is redundant in the sense that it can
be extracted from the "struct page" parameter by page_lru().

A caveat is that we need to make sure PageActive() or
PageUnevictable() is correctly set or cleared before calling
these two functions. And they are indeed.

Link: https://lore.kernel.org/linux-mm/20201207220949.830352-4-yuzhao@google.com/
Signed-off-by: Yu Zhao <yuzhao@google.com>
---
 include/linux/mm_inline.h |  8 ++++++--
 mm/swap.c                 | 15 +++++++--------
 mm/vmscan.c               |  6 ++----
 3 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index 2889741f450a..130ba3201d3f 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -106,15 +106,19 @@ static __always_inline enum lru_list page_lru(struct page *page)
 }
 
 static __always_inline void add_page_to_lru_list(struct page *page,
-				struct lruvec *lruvec, enum lru_list lru)
+				struct lruvec *lruvec)
 {
+	enum lru_list lru = page_lru(page);
+
 	update_lru_size(lruvec, lru, page_zonenum(page), thp_nr_pages(page));
 	list_add(&page->lru, &lruvec->lists[lru]);
 }
 
 static __always_inline void add_page_to_lru_list_tail(struct page *page,
-				struct lruvec *lruvec, enum lru_list lru)
+				struct lruvec *lruvec)
 {
+	enum lru_list lru = page_lru(page);
+
 	update_lru_size(lruvec, lru, page_zonenum(page), thp_nr_pages(page));
 	list_add_tail(&page->lru, &lruvec->lists[lru]);
 }
diff --git a/mm/swap.c b/mm/swap.c
index 490553f3f9ef..4b058ef37add 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -231,7 +231,7 @@ static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec)
 	if (!PageUnevictable(page)) {
 		del_page_from_lru_list(page, lruvec, page_lru(page));
 		ClearPageActive(page);
-		add_page_to_lru_list_tail(page, lruvec, page_lru(page));
+		add_page_to_lru_list_tail(page, lruvec);
 		__count_vm_events(PGROTATED, thp_nr_pages(page));
 	}
 }
@@ -313,8 +313,7 @@ static void __activate_page(struct page *page, struct lruvec *lruvec)
 
 		del_page_from_lru_list(page, lruvec, lru);
 		SetPageActive(page);
-		lru += LRU_ACTIVE;
-		add_page_to_lru_list(page, lruvec, lru);
+		add_page_to_lru_list(page, lruvec);
 		trace_mm_lru_activate(page);
 
 		__count_vm_events(PGACTIVATE, nr_pages);
@@ -543,14 +542,14 @@ static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec)
 		 * It can make readahead confusing.  But race window
 		 * is _really_ small and  it's non-critical problem.
 		 */
-		add_page_to_lru_list(page, lruvec, lru);
+		add_page_to_lru_list(page, lruvec);
 		SetPageReclaim(page);
 	} else {
 		/*
 		 * The page's writeback ends up during pagevec
 		 * We moves tha page into tail of inactive.
 		 */
-		add_page_to_lru_list_tail(page, lruvec, lru);
+		add_page_to_lru_list_tail(page, lruvec);
 		__count_vm_events(PGROTATED, nr_pages);
 	}
 
@@ -570,7 +569,7 @@ static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec)
 		del_page_from_lru_list(page, lruvec, lru + LRU_ACTIVE);
 		ClearPageActive(page);
 		ClearPageReferenced(page);
-		add_page_to_lru_list(page, lruvec, lru);
+		add_page_to_lru_list(page, lruvec);
 
 		__count_vm_events(PGDEACTIVATE, nr_pages);
 		__count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE,
@@ -595,7 +594,7 @@ static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec)
 		 * anonymous pages
 		 */
 		ClearPageSwapBacked(page);
-		add_page_to_lru_list(page, lruvec, LRU_INACTIVE_FILE);
+		add_page_to_lru_list(page, lruvec);
 
 		__count_vm_events(PGLAZYFREE, nr_pages);
 		__count_memcg_events(lruvec_memcg(lruvec), PGLAZYFREE,
@@ -1005,7 +1004,7 @@ static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec)
 			__count_vm_events(UNEVICTABLE_PGCULLED, nr_pages);
 	}
 
-	add_page_to_lru_list(page, lruvec, lru);
+	add_page_to_lru_list(page, lruvec);
 	trace_mm_lru_insertion(page, lru);
 }
 
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 19875660e8f8..09e4f97488c9 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1867,7 +1867,7 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 		 * inhibits memcg migration).
 		 */
 		VM_BUG_ON_PAGE(!lruvec_holds_page_lru_lock(page, lruvec), page);
-		add_page_to_lru_list(page, lruvec, page_lru(page));
+		add_page_to_lru_list(page, lruvec);
 		nr_pages = thp_nr_pages(page);
 		nr_moved += nr_pages;
 		if (PageActive(page))
@@ -4282,12 +4282,10 @@ void check_move_unevictable_pages(struct pagevec *pvec)
 
 		lruvec = relock_page_lruvec_irq(page, lruvec);
 		if (page_evictable(page) && PageUnevictable(page)) {
-			enum lru_list lru = page_lru_base_type(page);
-
 			VM_BUG_ON_PAGE(PageActive(page), page);
 			ClearPageUnevictable(page);
 			del_page_from_lru_list(page, lruvec, LRU_UNEVICTABLE);
-			add_page_to_lru_list(page, lruvec, lru);
+			add_page_to_lru_list(page, lruvec);
 			pgrescued += nr_pages;
 		}
 		SetPageLRU(page);
-- 
2.30.0.280.ga3ce27912f-goog