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 <[email protected]>
---
include/linux/vm_event_item.h | 1 +
mm/vmacache.c | 2 ++
mm/vmstat.c | 1 +
3 files changed, 4 insertions(+)
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 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
#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 @@ void vmacache_flush_all(struct mm_struct *mm)
{
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 1b12d39..10d7403 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -898,6 +898,7 @@ const char * const vmstat_text[] = {
#ifdef CONFIG_DEBUG_VM_VMACACHE
"vmacache_find_calls",
"vmacache_find_hits",
+ "vmacache_full_flushes",
#endif
#endif /* CONFIG_VM_EVENTS_COUNTERS */
};
--
1.8.4.5