linux-kernel - [PATCH v2 4/5] ksm: show ksmd status for auto mode

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Message-Id: <20220812101223.41641-1-xu.xin16@zte.com.cn>
Date:   Fri, 12 Aug 2022 10:12:23 +0000
From:   cgel.zte@...il.com
To:     akpm@...ux-foundation.org, willy@...radead.org
Cc:     hughd@...gle.com, izik.eidus@...ellosystems.com,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        xu.xin16@....com.cn, CGEL <cgel.zte@...il.com>
Subject: [PATCH v2 4/5] ksm: show ksmd status for auto mode

From: xu xin <xu.xin16@....com.cn>

Add a sysfs interface of ksmd_status to show some details related
with auto-mode.

Signed-off-by: xu xin <xu.xin16@....com.cn>
Signed-off-by: CGEL <cgel.zte@...il.com>
---
 mm/ksm.c | 42 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/mm/ksm.c b/mm/ksm.c
index c5fd4f520f4a..478bcf26bfcd 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -307,6 +307,9 @@ unsigned int ksm_auto_threshold = 20;
 /* Work in auto-mode. Whether trigger ksmd to compare and merge pages */
 static bool auto_triggered;
 
+/* Count of times that ksmd is triggered due to low free memory */
+static unsigned long triggered_times;
+
 #ifdef CONFIG_NUMA
 /* Zeroed when merging across nodes is not allowed */
 static unsigned int ksm_merge_across_nodes = 1;
@@ -2487,8 +2490,10 @@ static bool should_trigger_ksmd_to_merge(void)
 
 static inline void trigger_ksmd_to_merge(void)
 {
-	if (!auto_triggered)
+	if (!auto_triggered) {
+		triggered_times++;
 		auto_triggered = true;
+	}
 }
 
 static inline void stop_ksmd_to_merge(void)
@@ -3118,6 +3123,40 @@ static ssize_t run_store(struct kobject *kobj, struct kobj_attribute *attr,
 }
 KSM_ATTR(run);
 
+static ssize_t ksmd_status_show(struct kobject *kobj,
+				struct kobj_attribute *attr, char *buf)
+{
+	int len = 0;
+	unsigned int mergeable_mms = 0;
+	struct list_head *pos;
+
+	list_for_each(pos, &ksm_mm_head.mm_list)
+		mergeable_mms++;
+
+	if (ksm_run & KSM_RUN_AUTO) {
+		len += sysfs_emit_at(buf, len, "mode: auto\n");
+		len += sysfs_emit_at(buf, len, "auto_triggered: %d\n",
+						      auto_triggered);
+		len += sysfs_emit_at(buf, len, "mergeable_mms: %u\n",
+						       mergeable_mms);
+		len += sysfs_emit_at(buf, len, "scanning_factor: %u\n",
+						       scanning_factor);
+		len += sysfs_emit_at(buf, len, "triggered_times: %lu\n",
+						       triggered_times);
+	} else if (ksm_run & KSM_RUN_MERGE) {
+		len += sysfs_emit_at(buf, len, "mode: on\n");
+		len += sysfs_emit_at(buf, len, "mergeable_mms: %u\n",
+							mergeable_mms);
+	} else if (ksm_run & KSM_RUN_UNMERGE)
+		len += sysfs_emit_at(buf, len, "mode: unmerge\n");
+	else
+		len += sysfs_emit_at(buf, len, "mode: off\n");
+
+
+	return len;
+}
+KSM_ATTR_RO(ksmd_status);
+
 static ssize_t auto_threshold_show(struct kobject *kobj,
 						struct kobj_attribute *attr, char *buf)
 {
@@ -3355,6 +3394,7 @@ static struct attribute *ksm_attrs[] = {
 	&pages_to_scan_attr.attr,
 	&max_scanning_factor_attr.attr,
 	&run_attr.attr,
+	&ksmd_status_attr.attr,
 	&auto_threshold_attr.attr,
 	&pages_shared_attr.attr,
 	&pages_sharing_attr.attr,
-- 
2.25.1