[PATCH v2] mm/compaction: remove unused variable sysctl_compact_memory

[Pintu Kumar <pintu@codeaurora.org>]

The sysctl_compact_memory is mostly unused in mm/compaction.c
It just acts as a place holder for sysctl to store .data.

But the .data itself is not needed here.
So we can get ride of this variable completely and make .data as NULL.
This will also eliminate the extern declaration from header file.
No functionality is broken or changed this way.

Signed-off-by: Pintu Kumar <pintu@codeaurora.org>
Signed-off-by: Pintu Agarwal <pintu.ping@gmail.com>
---
v2: completely get rid of this variable and set .data to NULL
    Suggested-by: Vlastimil Babka <vbabka@suse.cz>

 include/linux/compaction.h | 1 -
 kernel/sysctl.c            | 2 +-
 mm/compaction.c            | 3 ---
 3 files changed, 1 insertion(+), 5 deletions(-)

diff --git a/include/linux/compaction.h b/include/linux/compaction.h
index ed4070e..4221888 100644
--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -81,7 +81,6 @@ static inline unsigned long compact_gap(unsigned int order)
 }
 
 #ifdef CONFIG_COMPACTION
-extern int sysctl_compact_memory;
 extern unsigned int sysctl_compaction_proactiveness;
 extern int sysctl_compaction_handler(struct ctl_table *table, int write,
 			void *buffer, size_t *length, loff_t *ppos);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c9fbdd8..07ef240 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2856,7 +2856,7 @@ static struct ctl_table vm_table[] = {
 #ifdef CONFIG_COMPACTION
 	{
 		.procname	= "compact_memory",
-		.data		= &sysctl_compact_memory,
+		.data		= NULL,
 		.maxlen		= sizeof(int),
 		.mode		= 0200,
 		.proc_handler	= sysctl_compaction_handler,
diff --git a/mm/compaction.c b/mm/compaction.c
index 190ccda..ede2886 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2650,9 +2650,6 @@ static void compact_nodes(void)
 		compact_node(nid);
 }
 
-/* The written value is actually unused, all memory is compacted */
-int sysctl_compact_memory;
-
 /*
  * Tunable for proactive compaction. It determines how
  * aggressively the kernel should compact memory in the
-- 
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