From 9a8d9aea4462a9efaff35f838d96d6df4f5741de Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: Fri, 5 Nov 2021 13:40:24 -0700
Subject: [PATCH] mm: move node_reclaim_distance to fix NUMA without SMP

References: bsc#1190208 (MM functional and performance backports)
Patch-mainline: v5.16-rc1
Git-commit: 61bb6cd2f765b90cfc5f0f91696889c366a6a13d

Patch series "Fix NUMA without SMP".

SuperH is the only architecture which still supports NUMA without SMP,
for good reasons (various memories scattered around the address space,
each with varying latencies).

This series fixes two build errors due to variables and functions used
by the NUMA code being provided by SMP-only source files or sections.

This patch (of 2):

If CONFIG_NUMA=y, but CONFIG_SMP=n (e.g. sh/migor_defconfig):

    sh4-linux-gnu-ld: mm/page_alloc.o: in function `get_page_from_freelist':
    page_alloc.c:(.text+0x2c24): undefined reference to `node_reclaim_distance'

Fix this by moving the declaration of node_reclaim_distance from an
SMP-only to a generic file.

Link: https://lkml.kernel.org/r/cover.1631781495.git.geert+renesas@glider.be
Link: https://lkml.kernel.org/r/6432666a648dde85635341e6c918cee97c97d264.1631781495.git.geert+renesas@glider.be
Fixes: a55c7454a8c887b2 ("sched/topology: Improve load balancing on AMD EPYC systems")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Suggested-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yoshinori Sato <ysato@users.osdn.me>
Cc: Rich Felker <dalias@libc.org>
Cc: Gon Solo <gonsolo@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
 kernel/sched/topology.c | 1 -
 mm/page_alloc.c         | 2 ++
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 2652f9749801..481d10d177c7 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1507,7 +1507,6 @@ static int			sched_domains_curr_level;
 int				sched_max_numa_distance;
 static int			*sched_domains_numa_distance;
 static struct cpumask		***sched_domains_numa_masks;
-int __read_mostly		node_reclaim_distance = RECLAIM_DISTANCE;
 
 static unsigned long __read_mostly *sched_numa_onlined_nodes;
 #endif
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 46eb7049e9d1..2eeef0e91f8a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3968,6 +3968,8 @@ bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
 }
 
 #ifdef CONFIG_NUMA
+int __read_mostly node_reclaim_distance = RECLAIM_DISTANCE;
+
 static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
 {
 	return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <=