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From:   "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To:     linux-mm@kvack.org, akpm@linux-foundation.org
Cc:     Wei Xu <weixugc@google.com>, Huang Ying <ying.huang@intel.com>,
        Yang Shi <shy828301@gmail.com>,
        Davidlohr Bueso <dave@stgolabs.net>,
        Tim C Chen <tim.c.chen@intel.com>,
        Michal Hocko <mhocko@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Hesham Almatary <hesham.almatary@huawei.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Alistair Popple <apopple@nvidia.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Johannes Weiner <hannes@cmpxchg.org>, jvgediya.oss@gmail.com,
        Bharata B Rao <bharata@amd.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Subject: [PATCH v15 07/10] mm/demotion: Drop memtier from memtype
Date:   Thu, 18 Aug 2022 18:40:39 +0530
Message-Id: <20220818131042.113280-8-aneesh.kumar@linux.ibm.com>
In-Reply-To: <20220818131042.113280-1-aneesh.kumar@linux.ibm.com>
References: <20220818131042.113280-1-aneesh.kumar@linux.ibm.com>
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Now that we track node-specific memtier in pg_data_t, we can drop
memtier from memtype.

Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 include/linux/memory-tiers.h |  1 -
 mm/memory-tiers.c            | 16 +++++++++-------
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
index 548e69f23727..108083d74557 100644
--- a/include/linux/memory-tiers.h
+++ b/include/linux/memory-tiers.h
@@ -28,7 +28,6 @@ struct memory_dev_type {
 	/* Nodes of same abstract distance */
 	nodemask_t nodes;
 	struct kref kref;
-	struct memory_tier *memtier;
 };
 
 #ifdef CONFIG_NUMA
diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index 2b7e91b45a75..455c104fab5d 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -100,17 +100,22 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty
 
 	lockdep_assert_held_once(&memory_tier_lock);
 
+	adistance = round_down(adistance, memtier_adistance_chunk_size);
 	/*
 	 * If the memtype is already part of a memory tier,
 	 * just return that.
 	 */
-	if (memtype->memtier)
-		return memtype->memtier;
+	if (!list_empty(&memtype->tier_sibiling)) {
+		list_for_each_entry(memtier, &memory_tiers, list) {
+			if (adistance == memtier->adistance_start)
+				return memtier;
+		}
+		WARN_ON(1);
+		return ERR_PTR(-EINVAL);
+	}
 
-	adistance = round_down(adistance, memtier_adistance_chunk_size);
 	list_for_each_entry(memtier, &memory_tiers, list) {
 		if (adistance == memtier->adistance_start) {
-			memtype->memtier = memtier;
 			list_add(&memtype->tier_sibiling, &memtier->memory_types);
 			return memtier;
 		} else if (adistance < memtier->adistance_start) {
@@ -130,7 +135,6 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty
 		list_add_tail(&new_memtier->list, &memtier->list);
 	else
 		list_add_tail(&new_memtier->list, &memory_tiers);
-	memtype->memtier = new_memtier;
 	list_add(&memtype->tier_sibiling, &new_memtier->memory_types);
 	return new_memtier;
 }
@@ -357,7 +361,6 @@ static bool clear_node_memory_tier(int node)
 		node_clear(node, memtype->nodes);
 		if (nodes_empty(memtype->nodes)) {
 			list_del(&memtype->tier_sibiling);
-			memtype->memtier = NULL;
 			if (list_empty(&memtier->memory_types))
 				destroy_memory_tier(memtier);
 		}
@@ -385,7 +388,6 @@ struct memory_dev_type *alloc_memory_type(int adistance)
 	memtype->adistance = adistance;
 	INIT_LIST_HEAD(&memtype->tier_sibiling);
 	memtype->nodes  = NODE_MASK_NONE;
-	memtype->memtier = NULL;
 	kref_init(&memtype->kref);
 	return memtype;
 }
-- 
2.37.2