0001-mm-vmstat-Add-OOM-kill-count-in-vmstat-counter.patch

From 234207c00620535bfae7fe89c5c2190aa229809b Mon Sep 17 00:00:00 2001
From: Pintu Kumar <pintu.k@samsung.com>
Date: Thu, 24 Sep 2015 10:24:45 +0530
Subject: [PATCH] mm: vmstat: Add OOM kill count in vmstat counter

This patch maintains number of oom calls and number of oom kill
count in /proc/vmstat.
It is helpful during sluggish, aging or long duration tests.
Currently if the OOM happens, it can be only seen in kernel ring buffer.
But during long duration tests, all the dmesg and /var/log/messages* could
be overwritten.
So, just like other counters, the oom can also be mainted in /proc/vmstat.
It can be also seen if all logs are disabled in kernel.
A snapshot of the result of over night test is shown below:
$ cat /proc/vmstat
oom_stall 610
oom_kill_count 1763

Here, oom_stall indicates that there are 610 times, kernel entered into OOM
cases. However, there were around 1763 oom killing happens.

Change-Id: I316f8d86061ea2cc9fd3f993436bbe0984e1deee
Signed-off-by: Pintu Kumar <pintu.k@samsung.com>
---
 include/linux/vm_event_item.h | 2 ++
 mm/oom_kill.c                 | 2 ++
 mm/page_alloc.c               | 1 +
 mm/vmstat.c                   | 2 ++
 4 files changed, 7 insertions(+)

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 68412c3..4e3809b 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -54,6 +54,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 #ifdef CONFIG_HUGETLB_PAGE
 		HTLB_BUDDY_PGALLOC, HTLB_BUDDY_PGALLOC_FAIL,
 #endif
+		OOM_STALL,
+		OOM_KILL_COUNT,
 		UNEVICTABLE_PGCULLED,	/* culled to noreclaim list */
 		UNEVICTABLE_PGSCANNED,	/* scanned for reclaimability */
 		UNEVICTABLE_PGRESCUED,	/* rescued from noreclaim list */
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 13cc6c0..bd5a6e7 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -552,11 +552,13 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
 				task_pid_nr(p), p->comm);
 			task_unlock(p);
 			do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
+			count_vm_event(OOM_KILL_COUNT);
 		}
 	rcu_read_unlock();
 
 	set_thread_group_flag(victim, TIF_MEMDIE);
 	do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, true);
+	count_vm_event(OOM_KILL_COUNT);
 	put_task_struct(victim);
 }
 #undef K
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index f71c010..50a5960 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2230,6 +2230,7 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
 	 * See freeze_processes.
 	 */
 	note_oom_kill();
+	count_vm_event(OOM_STALL);
 
 	/*
 	 * Go through the zonelist yet one more time, keep very high watermark
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 66d8941..aab24bb 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -821,6 +821,8 @@ const char * const vmstat_text[] = {
 	"compact_fail",
 	"compact_success",
 #endif
+	"oom_stall",
+	"oom_kill_count",
 
 #ifdef CONFIG_HUGETLB_PAGE
 	"htlb_buddy_alloc_success",
-- 
1.9.1