linux-kernel - [PATCH v8 41/63] mm: Convert huge

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Message-Id: <20180306192413.5499-42-willy@infradead.org>
Date:   Tue,  6 Mar 2018 11:23:51 -0800
From:   Matthew Wilcox <willy@...radead.org>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Matthew Wilcox <mawilcox@...rosoft.com>,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        linux-fsdevel@...r.kernel.org,
        Ryusuke Konishi <konishi.ryusuke@....ntt.co.jp>,
        linux-nilfs@...r.kernel.org, linux-btrfs@...r.kernel.org
Subject: [PATCH v8 41/63] mm: Convert huge_memory to XArray

From: Matthew Wilcox <mawilcox@...rosoft.com>

Quite a straightforward conversion.

Signed-off-by: Matthew Wilcox <mawilcox@...rosoft.com>
---
 mm/huge_memory.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 89737c0e0d34..354b7f768d0f 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2442,13 +2442,13 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 	ClearPageCompound(head);
 	/* See comment in __split_huge_page_tail() */
 	if (PageAnon(head)) {
-		/* Additional pin to radix tree of swap cache */
+		/* Additional pin to swap cache */
 		if (PageSwapCache(head))
 			page_ref_add(head, 2);
 		else
 			page_ref_inc(head);
 	} else {
-		/* Additional pin to radix tree */
+		/* Additional pin to page cache */
 		page_ref_add(head, 2);
 		xa_unlock(&head->mapping->i_pages);
 	}
@@ -2560,7 +2560,7 @@ bool can_split_huge_page(struct page *page, int *pextra_pins)
 {
 	int extra_pins;
 
-	/* Additional pins from radix tree */
+	/* Additional pins from page cache */
 	if (PageAnon(page))
 		extra_pins = PageSwapCache(page) ? HPAGE_PMD_NR : 0;
 	else
@@ -2656,17 +2656,14 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 	spin_lock_irqsave(zone_lru_lock(page_zone(head)), flags);
 
 	if (mapping) {
-		void **pslot;
+		XA_STATE(xas, &mapping->i_pages, page_index(head));
 
-		xa_lock(&mapping->i_pages);
-		pslot = radix_tree_lookup_slot(&mapping->i_pages,
-				page_index(head));
 		/*
-		 * Check if the head page is present in radix tree.
+		 * Check if the head page is present in page cache.
 		 * We assume all tail are present too, if head is there.
 		 */
-		if (radix_tree_deref_slot_protected(pslot,
-					&mapping->i_pages.xa_lock) != head)
+		xa_lock(&mapping->i_pages);
+		if (xas_load(&xas) != head)
 			goto fail;
 	}
 
-- 
2.16.1