mm, vmscan: add mm_vmscan_inactive_list_is_low tracepoint

Currently we have tracepoints for both active and inactive LRU lists
reclaim but we do not have any which would tell us why we we decided to
age the active list.  Without that it is quite hard to diagnose
active/inactive lists balancing.  Add mm_vmscan_inactive_list_is_low
tracepoint to tell us this information.

Link: http://lkml.kernel.org/r/20170104101942.4860-8-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 40 insertions, 0 deletions

diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h
index 08c1cd5af0d6..27e8a5c77579 100644
--- a/include/trace/events/vmscan.h
+++ b/include/trace/events/vmscan.h
@@ -15,6 +15,7 @@
 #define RECLAIM_WB_MIXED        0x0010u
 #define RECLAIM_WB_SYNC         0x0004u /* Unused, all reclaim async */
 #define RECLAIM_WB_ASYNC        0x0008u
+#define RECLAIM_WB_LRU          (RECLAIM_WB_ANON|RECLAIM_WB_FILE)
 
 #define show_reclaim_flags(flags)                               \
         (flags) ? __print_flags(flags, "|",                     \
@@ -426,6 +427,45 @@ TRACE_EVENT(mm_vmscan_lru_shrink_active,
                 show_reclaim_flags(__entry->reclaim_flags))
 );
 
+TRACE_EVENT(mm_vmscan_inactive_list_is_low,
+
+        TP_PROTO(int nid, int reclaim_idx,
+                unsigned long total_inactive, unsigned long inactive,
+                unsigned long total_active, unsigned long active,
+                unsigned long ratio, int file),
+
+        TP_ARGS(nid, reclaim_idx, total_inactive, inactive, total_active, active, ratio, file),
+
+        TP_STRUCT__entry(
+                __field(int, nid)
+                __field(int, reclaim_idx)
+                __field(unsigned long, total_inactive)
+                __field(unsigned long, inactive)
+                __field(unsigned long, total_active)
+                __field(unsigned long, active)
+                __field(unsigned long, ratio)
+                __field(int, reclaim_flags)
+        ),
+
+        TP_fast_assign(
+                __entry->nid = nid;
+                __entry->reclaim_idx = reclaim_idx;
+                __entry->total_inactive = total_inactive;
+                __entry->inactive = inactive;
+                __entry->total_active = total_active;
+                __entry->active = active;
+                __entry->ratio = ratio;
+                __entry->reclaim_flags = trace_shrink_flags(file) & RECLAIM_WB_LRU;
+        ),
+
+        TP_printk("nid=%d reclaim_idx=%d total_inactive=%ld inactive=%ld total_active=%ld active=%ld ratio=%ld flags=%s",
+                __entry->nid,
+                __entry->reclaim_idx,
+                __entry->total_inactive, __entry->inactive,
+                __entry->total_active, __entry->active,
+                __entry->ratio,
+                show_reclaim_flags(__entry->reclaim_flags))
+);
 #endif /* _TRACE_VMSCAN_H */
 
 /* This part must be outside protection */