[PATCH 6/9] io-wq: add infra data structure for fixed workers

[Hao Xu <haoxu@xxxxxxxxxxxxxxxxx>]

Add data sttructure and basic initialization for fixed worker.

Signed-off-by: Hao Xu <haoxu@xxxxxxxxxxxxxxxxx>
---
 fs/io-wq.c | 63 ++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 45 insertions(+), 18 deletions(-)

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 44c3e344c5d6..fcdfbb904cdf 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -25,6 +25,7 @@ enum {
 	IO_WORKER_F_RUNNING	= 2,	/* account as running */
 	IO_WORKER_F_FREE	= 4,	/* worker on free list */
 	IO_WORKER_F_BOUND	= 8,	/* is doing bounded work */
+	IO_WORKER_F_FIXED	= 16,	/* is a fixed worker */
 };
 
 enum {
@@ -33,6 +34,35 @@ enum {
 
 enum {
 	IO_ACCT_STALLED_BIT	= 0,	/* stalled on hash */
+	IO_ACCT_IN_WORKER_BIT,
+};
+
+struct io_wqe_acct {
+	union {
+		unsigned int nr_workers;
+		unsigned int nr_works;
+	};
+	union {
+		unsigned int max_workers;
+		unsigned int max_works;
+	};
+	int index;
+	atomic_t nr_running;
+	raw_spinlock_t lock;
+	struct io_wq_work_list work_list;
+	unsigned long flags;
+
+	struct wait_queue_entry wait;
+	union {
+		struct io_wqe *wqe;
+		struct io_worker *worker;
+	};
+};
+
+enum {
+	IO_WQ_ACCT_BOUND,
+	IO_WQ_ACCT_UNBOUND,
+	IO_WQ_ACCT_NR,
 };
 
 /*
@@ -59,6 +89,9 @@ struct io_worker {
 		struct rcu_head rcu;
 		struct work_struct work;
 	};
+	bool fixed;
+	unsigned int index;
+	struct io_wqe_acct acct;
 };
 
 #if BITS_PER_LONG == 64
@@ -69,24 +102,6 @@ struct io_worker {
 
 #define IO_WQ_NR_HASH_BUCKETS	(1u << IO_WQ_HASH_ORDER)
 
-struct io_wqe_acct {
-	unsigned nr_workers;
-	unsigned max_workers;
-	int index;
-	atomic_t nr_running;
-	raw_spinlock_t lock;
-	struct io_wq_work_list work_list;
-	unsigned long flags;
-	struct wait_queue_entry wait;
-	struct io_wqe *wqe;
-};
-
-enum {
-	IO_WQ_ACCT_BOUND,
-	IO_WQ_ACCT_UNBOUND,
-	IO_WQ_ACCT_NR,
-};
-
 /*
  * Per-node worker thread pool
  */
@@ -103,6 +118,12 @@ struct io_wqe {
 	struct io_wq_work *hash_tail[IO_WQ_NR_HASH_BUCKETS];
 
 	cpumask_var_t cpu_mask;
+
+	raw_spinlock_t fixed_lock;
+	unsigned int max_fixed[IO_WQ_ACCT_NR];
+	unsigned int nr_fixed[IO_WQ_ACCT_NR];
+	unsigned int default_max_works[IO_WQ_ACCT_NR];
+	struct io_worker **fixed_workers[IO_WQ_ACCT_NR];
 };
 
 /*
@@ -1090,6 +1111,8 @@ static int io_wqe_hash_wake(struct wait_queue_entry *wait, unsigned mode,
 	return 1;
 }
 
+#define DEFAULT_MAX_FIXED_WORKERS 0
+#define DEFAULT_MAX_FIXED_WORKS 0
 struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
 {
 	int ret, node, i;
@@ -1141,9 +1164,12 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
 			INIT_LIST_HEAD(&acct->wait.entry);
 			acct->wait.func = io_wqe_hash_wake;
 			acct->wqe = wqe;
+			wqe->max_fixed[i] = DEFAULT_MAX_FIXED_WORKERS;
+			wqe->default_max_works[i] = DEFAULT_MAX_FIXED_WORKS;
 		}
 		wqe->wq = wq;
 		raw_spin_lock_init(&wqe->lock);
+		raw_spin_lock_init(&wqe->fixed_lock);
 		INIT_HLIST_NULLS_HEAD(&wqe->free_list, 0);
 		INIT_LIST_HEAD(&wqe->all_list);
 	}
@@ -1232,6 +1258,7 @@ static void io_wq_destroy(struct io_wq *wq)
 		};
 		io_wqe_cancel_pending_work(wqe, &match);
 		free_cpumask_var(wqe->cpu_mask);
+		kfree(wqe->fixed_workers);
 		kfree(wqe);
 	}
 	io_wq_put_hash(wq->hash);
-- 
2.24.4