linux-kernel - [PATCH v3 2/2] mm: be more verbose about zonelist initialization

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Message-Id: <20190213094315.3504-1-mhocko@kernel.org>
Date:   Wed, 13 Feb 2019 10:43:15 +0100
From:   Michal Hocko <mhocko@...nel.org>
To:     <linux-mm@...ck.org>
Cc:     Pingfan Liu <kernelfans@...il.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Peter Zijlstra <peterz@...radead.org>, x86@...nel.org,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Tony Luck <tony.luck@...el.com>, linuxppc-dev@...ts.ozlabs.org,
        linux-ia64@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...e.hu>, Michal Hocko <mhocko@...e.com>
Subject: [PATCH v3 2/2] mm: be more verbose about zonelist initialization

From: Michal Hocko <mhocko@...e.com>

We have seen several bugs where zonelists have not been initialized
properly and it is not really straightforward to track those bugs down.
One way to help a bit at least is to dump zonelists of each node when
they are (re)initialized.

Signed-off-by: Michal Hocko <mhocko@...e.com>
---

Sorry for spamming. I have screwed up ammending the previous version.

 mm/page_alloc.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2e097f336126..52e54d16662a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5234,6 +5234,8 @@ static void build_zonelists(pg_data_t *pgdat)
 	int node, load, nr_nodes = 0;
 	nodemask_t used_mask;
 	int local_node, prev_node;
+	struct zone *zone;
+	struct zoneref *z;
 
 	/* NUMA-aware ordering of nodes */
 	local_node = pgdat->node_id;
@@ -5259,6 +5261,11 @@ static void build_zonelists(pg_data_t *pgdat)
 
 	build_zonelists_in_node_order(pgdat, node_order, nr_nodes);
 	build_thisnode_zonelists(pgdat);
+
+	pr_info("node[%d] zonelist: ", pgdat->node_id);
+	for_each_zone_zonelist(zone, z, &pgdat->node_zonelists[ZONELIST_FALLBACK], MAX_NR_ZONES-1)
+		pr_cont("%d:%s ", zone_to_nid(zone), zone->name);
+	pr_cont("\n");
 }
 
 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
-- 
2.20.1