linux-kernel - [PATCH 3/3] mm/vmalloc: switch to "propagate()" callback

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Message-Id: <20200527205054.1696-3-urezki@gmail.com>
Date:   Wed, 27 May 2020 22:50:54 +0200
From:   "Uladzislau Rezki (Sony)" <urezki@...il.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm@...ck.org, LKML <linux-kernel@...r.kernel.org>,
        Uladzislau Rezki <urezki@...il.com>,
        Hillf Danton <hdanton@...a.com>,
        Michal Hocko <mhocko@...e.com>,
        Matthew Wilcox <willy@...radead.org>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...ymobile.com>,
        Steven Rostedt <rostedt@...dmis.org>
Subject: [PATCH 3/3] mm/vmalloc: switch to "propagate()" callback

An augment_tree_propagate_from() function uses its own
implementation that populates a tree from the specified
node toward a root node.

>From the other hand the RB_DECLARE_CALLBACKS_MAX macro
provides the "propagate()" callback that does exactly
the same. Having two similar functions does not make
sense and is redundant.

Reuse "built in" functionality to the macros. So the
code size gets reduced.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
---
 mm/vmalloc.c | 25 ++++++-------------------
 1 file changed, 6 insertions(+), 19 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 62d48f5e7105..e3d5b8d1f987 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -633,25 +633,12 @@ augment_tree_propagate_check(void)
 static __always_inline void
 augment_tree_propagate_from(struct vmap_area *va)
 {
-	struct rb_node *node = &va->rb_node;
-	unsigned long new_va_sub_max_size;
-
-	while (node) {
-		va = rb_entry(node, struct vmap_area, rb_node);
-		new_va_sub_max_size = compute_subtree_max_size(va);
-
-		/*
-		 * If the newly calculated maximum available size of the
-		 * subtree is equal to the current one, then it means that
-		 * the tree is propagated correctly. So we have to stop at
-		 * this point to save cycles.
-		 */
-		if (va->subtree_max_size == new_va_sub_max_size)
-			break;
-
-		va->subtree_max_size = new_va_sub_max_size;
-		node = rb_parent(&va->rb_node);
-	}
+	/*
+	 * Populate the tree from bottom towards the root until
+	 * the calculated maximum available size of checked node
+	 * is equal to its current one.
+	 */
+	free_vmap_area_rb_augment_cb_propagate(&va->rb_node, NULL);
 
 #if DEBUG_AUGMENT_PROPAGATE_CHECK
 	augment_tree_propagate_check();
-- 
2.20.1