vmstat: Workaround for issue where dirty page count goes negative

popcornmix · popcornmix · commit 9172f3f1d128 · 2016-10-09T13:01:04.000+01:00
See: #617 http://www.spinics.net/lists/linux-mm/msg72236.html
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
@@ -222,7 +222,11 @@ 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
`@@ -222,7 +222,11 @@ static inline void __inc_zone_state(struct zone *zone, enum zone_stat_item item)`
`222`	`222`	`static inline void __dec_zone_state(struct zone *zone, enum zone_stat_item item)`
`223`	`223`	`{`
`224`	`224`	`atomic_long_dec(&zone->vm_stat[item]);`
	`225`	`+ if (item == NR_FILE_DIRTY && unlikely(atomic_long_read(&zone->vm_stat[item]) < 0))`
	`226`	`+ atomic_long_set(&zone->vm_stat[item], 0);`
`225`	`227`	`atomic_long_dec(&vm_stat[item]);`
	`228`	`+ if (item == NR_FILE_DIRTY && unlikely(atomic_long_read(&vm_stat[item]) < 0))`
	`229`	`+ atomic_long_set(&vm_stat[item], 0);`
`226`	`230`	`}`
`227`	`231`
`228`	`232`	`static inline void __inc_zone_page_state(struct page *page,`