mm: move node_reclaim_distance to fix NUMA without SMP

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>

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 4e8698e62f0754a39a0662a920b1a601814c00ae..738ee7fa79724c7d2974aa8860a0c5d5c28e4e61 100644 (file)
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1481,7 +1481,6 @@ 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 1eab16b4006d8f672066029cd8f58f59d0be635e..e4aef907abe9db5369416b71aa37b2fa9ede5b19 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3960,6 +3960,8 @@ 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)) <=