[1]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?i
d=facdaa917c4d5a376d09d25865f5a863f906234a

Signed-off-by: Charan Teja Reddy <redacted>
---
changes in V2:
    - remove /proc interface trigger for proactive compaction
    - Intention is same that add a way to trigger proactive compaction by user.

changes in V1:
    -
https://lore.kernel.org/lkml/1619098678-8501-1-git-send-email-charante@co
deaurora.org/

 include/linux/compaction.h |  2 ++
 include/linux/mmzone.h     |  1 +
 kernel/sysctl.c            |  2 +-
 mm/compaction.c            | 35
++++++++++++++++++++++++++++++++---
 4 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/include/linux/compaction.h b/include/linux/compaction.h index

4221888..04d5d9f 100644

--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h

@@ -84,6 +84,8 @@ static inline unsigned long compact_gap(unsigned int

order)  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);
+extern int compaction_proactiveness_sysctl_handler(struct ctl_table *table,
+		int write, void *buffer, size_t *length, loff_t *ppos);
 extern int sysctl_extfrag_threshold;
 extern int sysctl_compact_unevictable_allowed;

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index

0d53eba..9455809 100644

--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h

@@ -815,6 +815,7 @@ typedef struct pglist_data {
 	enum zone_type kcompactd_highest_zoneidx;
 	wait_queue_head_t kcompactd_wait;
 	struct task_struct *kcompactd;
+	bool proactive_compact_trigger;
 #endif
 	/*
 	 * This is a per-node reserve of pages that are not available diff --git

a/kernel/sysctl.c b/kernel/sysctl.c index 14edf84..bed2fad 100644

--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c

@@ -2840,7 +2840,7 @@ static struct ctl_table vm_table[] = {
 		.data		= &sysctl_compaction_proactiveness,
 		.maxlen		= sizeof(sysctl_compaction_proactiveness),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= compaction_proactiveness_sysctl_handler,
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= &one_hundred,
 	},

diff --git a/mm/compaction.c b/mm/compaction.c index 84fde27..9056693

100644

--- a/mm/compaction.c
+++ b/mm/compaction.c

@@ -2708,6 +2708,30 @@ static void compact_nodes(void)
  */
 unsigned int __read_mostly sysctl_compaction_proactiveness = 20;

+int compaction_proactiveness_sysctl_handler(struct ctl_table *table, int

write,
+		void *buffer, size_t *length, loff_t *ppos) {
+	int rc, nid;
+
+	rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
+	if (rc)
+		return rc;
+
+	if (write && sysctl_compaction_proactiveness) {
+		for_each_online_node(nid) {
+			pg_data_t *pgdat = NODE_DATA(nid);
+
+			if (pgdat->proactive_compact_trigger)
+				continue;
+
+			pgdat->proactive_compact_trigger = true;
+			wake_up_interruptible(&pgdat->kcompactd_wait);
+		}
+	}
+
+	return 0;
+}
+
 /*
  * This is the entry point for compacting all nodes via
  * /proc/sys/vm/compact_memory

@@ -2752,7 +2776,8 @@ void compaction_unregister_node(struct node

*node)

 static inline bool kcompactd_work_requested(pg_data_t *pgdat)  {
-	return pgdat->kcompactd_max_order > 0 || kthread_should_stop();
+	return pgdat->kcompactd_max_order > 0 || kthread_should_stop() ||
+		pgdat->proactive_compact_trigger;
 }

 static bool kcompactd_node_suitable(pg_data_t *pgdat) @@ -2905,7
+2930,8 @@ static int kcompactd(void *p)
 		trace_mm_compaction_kcompactd_sleep(pgdat->node_id);
 		if (wait_event_freezable_timeout(pgdat->kcompactd_wait,
 			kcompactd_work_requested(pgdat),
-			msecs_to_jiffies(HPAGE_FRAG_CHECK_INTERVAL_MSEC))) {
+			msecs_to_jiffies(HPAGE_FRAG_CHECK_INTERVAL_MSEC)) &&
+			!pgdat->proactive_compact_trigger) {

 			psi_memstall_enter(&pflags);
 			kcompactd_do_work(pgdat);

@@ -2919,7 +2945,7 @@ static int kcompactd(void *p)

 			if (proactive_defer) {
 				proactive_defer--;
-				continue;
+				goto loop;
 			}
 			prev_score = fragmentation_score_node(pgdat);
 			proactive_compact_node(pgdat);

@@ -2931,6 +2957,9 @@ static int kcompactd(void *p)
 			proactive_defer = score < prev_score ?
 					0 : 1 << COMPACT_MAX_DEFER_SHIFT;
 		}
+loop:
+		if (pgdat->proactive_compact_trigger)
+			pgdat->proactive_compact_trigger = false;
 	}

 	return 0;
--

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