mm,vmacache: count number of system-wide flushes
These flushes deal with sequence number overflows, such as for long lived
threads. These are rare, but interesting from a debugging PoV. As such,
display the number of flushes when vmacache debugging is enabled.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 730334c..9246d32 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -90,6 +90,7 @@
#ifdef CONFIG_DEBUG_VM_VMACACHE
VMACACHE_FIND_CALLS,
VMACACHE_FIND_HITS,
+ VMACACHE_FULL_FLUSHES,
#endif
NR_VM_EVENT_ITEMS
};
diff --git a/mm/vmacache.c b/mm/vmacache.c
index 9f25af8..b6e3662 100644
--- a/mm/vmacache.c
+++ b/mm/vmacache.c
@@ -17,6 +17,8 @@
{
struct task_struct *g, *p;
+ count_vm_vmacache_event(VMACACHE_FULL_FLUSHES);
+
/*
* Single threaded tasks need not iterate the entire
* list of process. We can avoid the flushing as well
diff --git a/mm/vmstat.c b/mm/vmstat.c
index b090e9e..1284f89 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -900,6 +900,7 @@
#ifdef CONFIG_DEBUG_VM_VMACACHE
"vmacache_find_calls",
"vmacache_find_hits",
+ "vmacache_full_flushes",
#endif
#endif /* CONFIG_VM_EVENTS_COUNTERS */
};