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* [PATCH v2] mm: vmscan: add tracepoints for node reclaim
@ 2019-03-01  6:24 Yafang Shao
  2019-03-01  6:24 ` [PATCH] mm: vmscan: drop may_writepage and classzone_idx from direct reclaim begin template Yafang Shao
  2019-03-01  8:38 ` [PATCH v2] mm: vmscan: add tracepoints for node reclaim Souptick Joarder
  0 siblings, 2 replies; 6+ messages in thread
From: Yafang Shao @ 2019-03-01  6:24 UTC (permalink / raw)
  To: vbabka, mhocko, jrdr.linux
  Cc: akpm, linux-mm, linux-kernel, shaoyafang, Yafang Shao

In the page alloc fast path, it may do node reclaim, which may cause
latency spike.
We should add tracepoint for this event, and also measure the latency
it causes.

So bellow two tracepoints are introduced,
	mm_vmscan_node_reclaim_begin
	mm_vmscan_node_reclaim_end

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
 include/trace/events/vmscan.h | 32 ++++++++++++++++++++++++++++++++
 mm/vmscan.c                   |  6 ++++++
 2 files changed, 38 insertions(+)

diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h
index a1cb913..c1ddf28 100644
--- a/include/trace/events/vmscan.h
+++ b/include/trace/events/vmscan.h
@@ -465,6 +465,38 @@
 		__entry->ratio,
 		show_reclaim_flags(__entry->reclaim_flags))
 );
+
+TRACE_EVENT(mm_vmscan_node_reclaim_begin,
+
+	TP_PROTO(int nid, int order, gfp_t gfp_flags),
+
+	TP_ARGS(nid, order, gfp_flags),
+
+	TP_STRUCT__entry(
+		__field(int, nid)
+		__field(int, order)
+		__field(gfp_t, gfp_flags)
+	),
+
+	TP_fast_assign(
+		__entry->nid = nid;
+		__entry->order = order;
+		__entry->gfp_flags = gfp_flags;
+	),
+
+	TP_printk("nid=%d order=%d gfp_flags=%s",
+		__entry->nid,
+		__entry->order,
+		show_gfp_flags(__entry->gfp_flags))
+);
+
+DEFINE_EVENT(mm_vmscan_direct_reclaim_end_template, mm_vmscan_node_reclaim_end,
+
+	TP_PROTO(unsigned long nr_reclaimed),
+
+	TP_ARGS(nr_reclaimed)
+);
+
 #endif /* _TRACE_VMSCAN_H */
 
 /* This part must be outside protection */
diff --git a/mm/vmscan.c b/mm/vmscan.c
index ac4806f..2bee5d1 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4241,6 +4241,9 @@ static int __node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned in
 		.reclaim_idx = gfp_zone(gfp_mask),
 	};
 
+	trace_mm_vmscan_node_reclaim_begin(pgdat->node_id, order,
+					   sc.gfp_mask);
+
 	cond_resched();
 	fs_reclaim_acquire(sc.gfp_mask);
 	/*
@@ -4267,6 +4270,9 @@ static int __node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned in
 	current->flags &= ~PF_SWAPWRITE;
 	memalloc_noreclaim_restore(noreclaim_flag);
 	fs_reclaim_release(sc.gfp_mask);
+
+	trace_mm_vmscan_node_reclaim_end(sc.nr_reclaimed);
+
 	return sc.nr_reclaimed >= nr_pages;
 }
 
-- 
1.8.3.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2019-03-14 10:44 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-03-01  6:24 [PATCH v2] mm: vmscan: add tracepoints for node reclaim Yafang Shao
2019-03-01  6:24 ` [PATCH] mm: vmscan: drop may_writepage and classzone_idx from direct reclaim begin template Yafang Shao
2019-03-14  9:43   ` Yafang Shao
2019-03-14 10:19   ` Michal Hocko
2019-03-14 10:43     ` Yafang Shao
2019-03-01  8:38 ` [PATCH v2] mm: vmscan: add tracepoints for node reclaim Souptick Joarder

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