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From:   Michal Hocko <mhocko@kernel.org>
To:     <linux-mm@kvack.org>
Cc:     Pingfan Liu <kernelfans@gmail.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Peter Zijlstra <peterz@infradead.org>, x86@kernel.org,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Tony Luck <tony.luck@intel.com>, linuxppc-dev@lists.ozlabs.org,
        linux-ia64@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@elte.hu>, Michal Hocko <mhocko@suse.com>
Subject: [PATCH v2 2/2] mm: be more verbose about zonelist initialization
Date:   Wed, 13 Feb 2019 10:40:34 +0100
Message-Id: <20190213094034.1341-1-mhocko@kernel.org>
In-Reply-To: <20190212095343.23315-3-mhocko@kernel.org>
References: <20190212095343.23315-3-mhocko@kernel.org>
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From: Michal Hocko <mhocko@suse.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@suse.com>
---
 mm/page_alloc.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2e097f336126..02c843f0db4f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5234,6 +5234,7 @@ 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;
 
 	/* NUMA-aware ordering of nodes */
 	local_node = pgdat->node_id;
@@ -5259,6 +5260,11 @@ 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