From 132bb8cfc9e081238e7e2fd0c37c8c75ad0d2963 Mon Sep 17 00:00:00 2001
From: Yafang Shao <laoar.shao@gmail.com>
Date: Mon, 13 May 2019 17:17:53 -0700
Subject: [PATCH] mm/vmscan: add tracepoints for node reclaim
The page alloc fast path it may perform node reclaim, which may cause a
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
Link: http://lkml.kernel.org/r/1551421452-5385-1-git-send-email-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: <shaoyafang@didiglobal.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
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 cb2add69301a..b8b9d42944f9 100644
--- a/include/trace/events/vmscan.h
+++ b/include/trace/events/vmscan.h
@@ -469,6 +469,38 @@ TRACE_EVENT(mm_vmscan_inactive_list_is_low,
__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 40ff747e0b33..39912c6b7181 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4111,6 +4111,9 @@ 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);
/*
@@ -4137,6 +4140,9 @@ 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;
}
--
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