Received-SPF: pass (google.com: domain of linux-kernel+bounces-132281-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
From: "Ho-Ren (Jack) Chuang" <horenchuang@bytedance.com>
To: "Jonathan Cameron" <Jonathan.Cameron@Huawei.com>,
	"Huang, Ying" <ying.huang@intel.com>,
	"Gregory Price" <gourry.memverge@gmail.com>,
	aneesh.kumar@linux.ibm.com,
	mhocko@suse.com,
	tj@kernel.org,
	john@jagalactic.com,
	"Eishan Mirakhur" <emirakhur@micron.com>,
	"Vinicius Tavares Petrucci" <vtavarespetr@micron.com>,
	"Ravis OpenSrc" <Ravis.OpenSrc@micron.com>,
	"Alistair Popple" <apopple@nvidia.com>,
	"Srinivasulu Thanneeru" <sthanneeru@micron.com>,
	"SeongJae Park" <sj@kernel.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	nvdimm@lists.linux.dev,
	linux-cxl@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-mm@kvack.org
Cc: "Ho-Ren (Jack) Chuang" <horenc@vt.edu>,
	"Ho-Ren (Jack) Chuang" <horenchuang@bytedance.com>,
	"Ho-Ren (Jack) Chuang" <horenchuang@gmail.com>,
	qemu-devel@nongnu.org
Subject: [PATCH v11 1/2] memory tier: dax/kmem: introduce an abstract layer for finding, allocating, and putting memory types
Date: Fri,  5 Apr 2024 00:07:05 +0000
Message-Id: <20240405000707.2670063-2-horenchuang@bytedance.com>
In-Reply-To: <20240405000707.2670063-1-horenchuang@bytedance.com>
References: <20240405000707.2670063-1-horenchuang@bytedance.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

Since different memory devices require finding, allocating, and putting
memory types, these common steps are abstracted in this patch,
enhancing the scalability and conciseness of the code.

Signed-off-by: Ho-Ren (Jack) Chuang <horenchuang@bytedance.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
---
 drivers/dax/kmem.c           | 30 ++++--------------------------
 include/linux/memory-tiers.h | 13 +++++++++++++
 mm/memory-tiers.c            | 29 +++++++++++++++++++++++++++++
 3 files changed, 46 insertions(+), 26 deletions(-)

diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index 42ee360cf4e3..4fe9d040e375 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -55,36 +55,14 @@ static LIST_HEAD(kmem_memory_types);
 
 static struct memory_dev_type *kmem_find_alloc_memory_type(int adist)
 {
-	bool found = false;
-	struct memory_dev_type *mtype;
-
-	mutex_lock(&kmem_memory_type_lock);
-	list_for_each_entry(mtype, &kmem_memory_types, list) {
-		if (mtype->adistance == adist) {
-			found = true;
-			break;
-		}
-	}
-	if (!found) {
-		mtype = alloc_memory_type(adist);
-		if (!IS_ERR(mtype))
-			list_add(&mtype->list, &kmem_memory_types);
-	}
-	mutex_unlock(&kmem_memory_type_lock);
-
-	return mtype;
+	guard(mutex)(&kmem_memory_type_lock);
+	return mt_find_alloc_memory_type(adist, &kmem_memory_types);
 }
 
 static void kmem_put_memory_types(void)
 {
-	struct memory_dev_type *mtype, *mtn;
-
-	mutex_lock(&kmem_memory_type_lock);
-	list_for_each_entry_safe(mtype, mtn, &kmem_memory_types, list) {
-		list_del(&mtype->list);
-		put_memory_type(mtype);
-	}
-	mutex_unlock(&kmem_memory_type_lock);
+	guard(mutex)(&kmem_memory_type_lock);
+	mt_put_memory_types(&kmem_memory_types);
 }
 
 static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
index 69e781900082..0d70788558f4 100644
--- a/include/linux/memory-tiers.h
+++ b/include/linux/memory-tiers.h
@@ -48,6 +48,9 @@ int mt_calc_adistance(int node, int *adist);
 int mt_set_default_dram_perf(int nid, struct access_coordinate *perf,
 			     const char *source);
 int mt_perf_to_adistance(struct access_coordinate *perf, int *adist);
+struct memory_dev_type *mt_find_alloc_memory_type(int adist,
+						  struct list_head *memory_types);
+void mt_put_memory_types(struct list_head *memory_types);
 #ifdef CONFIG_MIGRATION
 int next_demotion_node(int node);
 void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets);
@@ -136,5 +139,15 @@ static inline int mt_perf_to_adistance(struct access_coordinate *perf, int *adis
 {
 	return -EIO;
 }
+
+static inline struct memory_dev_type *mt_find_alloc_memory_type(int adist,
+								struct list_head *memory_types)
+{
+	return NULL;
+}
+
+static inline void mt_put_memory_types(struct list_head *memory_types)
+{
+}
 #endif	/* CONFIG_NUMA */
 #endif  /* _LINUX_MEMORY_TIERS_H */
diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index 0537664620e5..516b144fd45a 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -623,6 +623,35 @@ void clear_node_memory_type(int node, struct memory_dev_type *memtype)
 }
 EXPORT_SYMBOL_GPL(clear_node_memory_type);
 
+struct memory_dev_type *mt_find_alloc_memory_type(int adist, struct list_head *memory_types)
+{
+	struct memory_dev_type *mtype;
+
+	list_for_each_entry(mtype, memory_types, list)
+		if (mtype->adistance == adist)
+			return mtype;
+
+	mtype = alloc_memory_type(adist);
+	if (IS_ERR(mtype))
+		return mtype;
+
+	list_add(&mtype->list, memory_types);
+
+	return mtype;
+}
+EXPORT_SYMBOL_GPL(mt_find_alloc_memory_type);
+
+void mt_put_memory_types(struct list_head *memory_types)
+{
+	struct memory_dev_type *mtype, *mtn;
+
+	list_for_each_entry_safe(mtype, mtn, memory_types, list) {
+		list_del(&mtype->list);
+		put_memory_type(mtype);
+	}
+}
+EXPORT_SYMBOL_GPL(mt_put_memory_types);
+
 static void dump_hmem_attrs(struct access_coordinate *coord, const char *prefix)
 {
 	pr_info(
-- 
Ho-Ren (Jack) Chuang