linux-kernel - Re: [bug, 4.8] /proc/meminfo: counter values are very wrong

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Message-ID: <20160804123458.GL2799@techsingularity.net>
Date:	Thu, 4 Aug 2016 13:34:58 +0100
From:	Mel Gorman <mgorman@...hsingularity.net>
To:	Dave Chinner <david@...morbit.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [bug, 4.8] /proc/meminfo: counter values are very wrong

On Thu, Aug 04, 2016 at 01:24:09PM +0100, Mel Gorman wrote:
> On Thu, Aug 04, 2016 at 03:10:51PM +1000, Dave Chinner wrote:
> > Hi folks,
> > 
> > I just noticed a whacky memory usage profile when running some basic
> > IO tests on a current 4.8 tree. It looked like there was a massive
> > memory leak from my monitoring graphs - doing buffered IO was
> > causing huge amounts of memory to be considered used, but the cache
> > size was not increasing.
> > 
> > Looking at /proc/meminfo:
> > 
> > $ cat /proc/meminfo
> > MemTotal:       16395408 kB
> > MemFree:           79424 kB
> > MemAvailable:    2497240 kB
> > Buffers:            4372 kB
> > Cached:           558744 kB
> > SwapCached:           48 kB
> > Active:          2127212 kB
> > Inactive:         100400 kB
> > Active(anon):      25348 kB
> > Inactive(anon):    79424 kB
> > Active(file):    2101864 kB
> > Inactive(file):    20976 kB
> > Unevictable:    13612980 kB	<<<<<<<<<
> 
> This? Very quickly done, no boot testing
> 

Or better yet, this. This is aimed at the proc reporting only.

diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index 09e18fdf61e5..b9a8c813e5e6 100644
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -46,7 +46,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
 		cached = 0;
 
 	for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
-		pages[lru] = global_page_state(NR_LRU_BASE + lru);
+		pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
 
 	available = si_mem_available();
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index fb975cec3518..baa97da3687d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4064,7 +4064,7 @@ long si_mem_available(void)
 	int lru;
 
 	for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
-		pages[lru] = global_page_state(NR_LRU_BASE + lru);
+		pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
 
 	for_each_zone(zone)
 		wmark_low += zone->watermark[WMARK_LOW];

-- 
Mel Gorman
SUSE Labs