ksm: Add showmem notifier

KSM is yet another framework which may obfuscate some memory
problems. Use the showmem notifier to show how KSM is being
used to give some insight into potential issues or non-issues.

Change-Id: If82405dc33f212d085e6847f7c511fd4d0a32a10
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/mm/ksm.c b/mm/ksm.c
index 1ba25cfb94ab..4bf14d0e3a8a 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -37,6 +37,7 @@
 #include <linux/freezer.h>
 #include <linux/oom.h>
 #include <linux/numa.h>
+#include <linux/show_mem_notifier.h>
 
 #include <asm/tlbflush.h>
 #include "internal.h"
@@ -250,6 +251,20 @@ static DEFINE_SPINLOCK(ksm_mmlist_lock);
 		sizeof(struct __struct), __alignof__(struct __struct),\
 		(__flags), NULL)
 
+static int ksm_show_mem_notifier(struct notifier_block *nb,
+				unsigned long action,
+				void *data)
+{
+	pr_info("ksm_pages_sharing: %lu\n", ksm_pages_sharing);
+	pr_info("ksm_pages_shared: %lu\n", ksm_pages_shared);
+
+	return 0;
+}
+
+static struct notifier_block ksm_show_mem_notifier_block = {
+	.notifier_call = ksm_show_mem_notifier,
+};
+
 static int __init ksm_slab_init(void)
 {
 	rmap_item_cache = KSM_KMEM_CACHE(rmap_item, 0);
@@ -2415,6 +2430,8 @@ static int __init ksm_init(void)
 	/* There is no significance to this priority 100 */
 	hotplug_memory_notifier(ksm_memory_callback, 100);
 #endif
+
+	show_mem_notifier_register(&ksm_show_mem_notifier_block);
 	return 0;
 
 out_free: