[RFC PATCH 5/7] mm/slab: move kfree_rcu_cpu[_work] definitions

[Harry Yoo <harry.yoo@oracle.com>]

In preparation for defining kfree_rcu_cpu under
CONFIG_KVFREE_RCU_BATCHED=n and adding a new function common to both
configurations, move the existing kfree_rcu_cpu[_work] definitions to
just before the beginning of the kfree_rcu batching infrastructure.

Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
---
 mm/slab_common.c | 142 ++++++++++++++++++++++++-----------------------
 1 file changed, 72 insertions(+), 70 deletions(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 3ec99a5463d3..d232b99a4b52 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1263,78 +1263,9 @@ EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
 EXPORT_TRACEPOINT_SYMBOL(kfree);
 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
 
-#ifndef CONFIG_KVFREE_RCU_BATCHED
-
-void kvfree_call_rcu_head(struct rcu_head *head, void *ptr)
-{
-	if (head) {
-		kasan_record_aux_stack(ptr);
-		call_rcu(head, kvfree_rcu_cb);
-		return;
-	}
-
-	// kvfree_rcu(one_arg) call.
-	might_sleep();
-	synchronize_rcu();
-	kvfree(ptr);
-}
-EXPORT_SYMBOL_GPL(kvfree_call_rcu_head);
-
-void __init kvfree_rcu_init(void)
-{
-}
-
-#else /* CONFIG_KVFREE_RCU_BATCHED */
-
-/*
- * This rcu parameter is runtime-read-only. It reflects
- * a minimum allowed number of objects which can be cached
- * per-CPU. Object size is equal to one page. This value
- * can be changed at boot time.
- */
-static int rcu_min_cached_objs = 5;
-module_param(rcu_min_cached_objs, int, 0444);
-
-// A page shrinker can ask for pages to be freed to make them
-// available for other parts of the system. This usually happens
-// under low memory conditions, and in that case we should also
-// defer page-cache filling for a short time period.
-//
-// The default value is 5 seconds, which is long enough to reduce
-// interference with the shrinker while it asks other systems to
-// drain their caches.
-static int rcu_delay_page_cache_fill_msec = 5000;
-module_param(rcu_delay_page_cache_fill_msec, int, 0444);
-
-static struct workqueue_struct *rcu_reclaim_wq;
-
-/* Maximum number of jiffies to wait before draining a batch. */
-#define KFREE_DRAIN_JIFFIES (5 * HZ)
+#ifdef CONFIG_KVFREE_RCU_BATCHED
 #define KFREE_N_BATCHES 2
 #define FREE_N_CHANNELS 2
-
-/**
- * struct kvfree_rcu_bulk_data - single block to store kvfree_rcu() pointers
- * @list: List node. All blocks are linked between each other
- * @gp_snap: Snapshot of RCU state for objects placed to this bulk
- * @nr_records: Number of active pointers in the array
- * @records: Array of the kvfree_rcu() pointers
- */
-struct kvfree_rcu_bulk_data {
-	struct list_head list;
-	struct rcu_gp_oldstate gp_snap;
-	unsigned long nr_records;
-	void *records[] __counted_by(nr_records);
-};
-
-/*
- * This macro defines how many entries the "records" array
- * will contain. It is based on the fact that the size of
- * kvfree_rcu_bulk_data structure becomes exactly one page.
- */
-#define KVFREE_BULK_MAX_ENTR \
-	((PAGE_SIZE - sizeof(struct kvfree_rcu_bulk_data)) / sizeof(void *))
-
 /**
  * struct kfree_rcu_cpu_work - single batch of kfree_rcu() requests
  * @rcu_work: Let queue_rcu_work() invoke workqueue handler after grace period
@@ -1402,6 +1333,77 @@ struct kfree_rcu_cpu {
 	struct llist_head bkvcache;
 	int nr_bkv_objs;
 };
+#endif
+
+#ifndef CONFIG_KVFREE_RCU_BATCHED
+
+void kvfree_call_rcu_head(struct rcu_head *head, void *ptr)
+{
+	if (head) {
+		kasan_record_aux_stack(ptr);
+		call_rcu(head, kvfree_rcu_cb);
+		return;
+	}
+
+	// kvfree_rcu(one_arg) call.
+	might_sleep();
+	synchronize_rcu();
+	kvfree(ptr);
+}
+EXPORT_SYMBOL_GPL(kvfree_call_rcu_head);
+
+void __init kvfree_rcu_init(void)
+{
+}
+
+#else /* CONFIG_KVFREE_RCU_BATCHED */
+
+/*
+ * This rcu parameter is runtime-read-only. It reflects
+ * a minimum allowed number of objects which can be cached
+ * per-CPU. Object size is equal to one page. This value
+ * can be changed at boot time.
+ */
+static int rcu_min_cached_objs = 5;
+module_param(rcu_min_cached_objs, int, 0444);
+
+// A page shrinker can ask for pages to be freed to make them
+// available for other parts of the system. This usually happens
+// under low memory conditions, and in that case we should also
+// defer page-cache filling for a short time period.
+//
+// The default value is 5 seconds, which is long enough to reduce
+// interference with the shrinker while it asks other systems to
+// drain their caches.
+static int rcu_delay_page_cache_fill_msec = 5000;
+module_param(rcu_delay_page_cache_fill_msec, int, 0444);
+
+static struct workqueue_struct *rcu_reclaim_wq;
+
+/* Maximum number of jiffies to wait before draining a batch. */
+#define KFREE_DRAIN_JIFFIES (5 * HZ)
+
+/**
+ * struct kvfree_rcu_bulk_data - single block to store kvfree_rcu() pointers
+ * @list: List node. All blocks are linked between each other
+ * @gp_snap: Snapshot of RCU state for objects placed to this bulk
+ * @nr_records: Number of active pointers in the array
+ * @records: Array of the kvfree_rcu() pointers
+ */
+struct kvfree_rcu_bulk_data {
+	struct list_head list;
+	struct rcu_gp_oldstate gp_snap;
+	unsigned long nr_records;
+	void *records[] __counted_by(nr_records);
+};
+
+/*
+ * This macro defines how many entries the "records" array
+ * will contain. It is based on the fact that the size of
+ * kvfree_rcu_bulk_data structure becomes exactly one page.
+ */
+#define KVFREE_BULK_MAX_ENTR \
+	((PAGE_SIZE - sizeof(struct kvfree_rcu_bulk_data)) / sizeof(void *))
 
 static DEFINE_PER_CPU(struct kfree_rcu_cpu, krc) = {
 	.lock = __RAW_SPIN_LOCK_UNLOCKED(krc.lock),
-- 
2.43.0