vmstat: Workaround for issue where dirty page count goes negative

popcornmix · popcornmix · commit 9c43a1c4012c · 2014-10-31T18:03:10.000Z
See: #617 http://www.spinics.net/lists/linux-mm/msg72236.html
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
@@ -241,7 +241,11 @@ static inline void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 static inline void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 {
 	atomic_long_dec(&zone->vm_stat[item]);
+	if (item == NR_FILE_DIRTY && unlikely(atomic_long_read(&zone->vm_stat[item]) < 0))
+		atomic_long_set(&zone->vm_stat[item], 0);
 	atomic_long_dec(&vm_stat[item]);
+	if (item == NR_FILE_DIRTY && unlikely(atomic_long_read(&vm_stat[item]) < 0))
+		atomic_long_set(&vm_stat[item], 0);
 }
 
 static inline void __inc_zone_page_state(struct page *page,

Original file line number	Diff line number	Diff line change
`@@ -241,7 +241,11 @@ static inline void __inc_zone_state(struct zone *zone, enum zone_stat_item item)`
`241`	`241`	`static inline void __dec_zone_state(struct zone *zone, enum zone_stat_item item)`
`242`	`242`	`{`
`243`	`243`	`atomic_long_dec(&zone->vm_stat[item]);`
	`244`	`+ if (item == NR_FILE_DIRTY && unlikely(atomic_long_read(&zone->vm_stat[item]) < 0))`
	`245`	`+ atomic_long_set(&zone->vm_stat[item], 0);`
`244`	`246`	`atomic_long_dec(&vm_stat[item]);`
	`247`	`+ if (item == NR_FILE_DIRTY && unlikely(atomic_long_read(&vm_stat[item]) < 0))`
	`248`	`+ atomic_long_set(&vm_stat[item], 0);`
`245`	`249`	`}`
`246`	`250`
`247`	`251`	`static inline void __inc_zone_page_state(struct page *page,`