inet: reduce TLB pressure for listeners

It seems overkill to use vmalloc() for typical listeners with less than
2048 hash buckets. Try kmalloc() and fallback to vmalloc() to reduce TLB
pressure.

Use kvfree() helper as it is now available.
Use ilog2() instead of a loop.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/request_sock.c b/net/core/request_sock.c
index 467f326..04db318 100644
--- a/net/core/request_sock.c
+++ b/net/core/request_sock.c
@@ -41,27 +41,27 @@
 		      unsigned int nr_table_entries)
 {
 	size_t lopt_size = sizeof(struct listen_sock);
-	struct listen_sock *lopt;
+	struct listen_sock *lopt = NULL;
 
 	nr_table_entries = min_t(u32, nr_table_entries, sysctl_max_syn_backlog);
 	nr_table_entries = max_t(u32, nr_table_entries, 8);
 	nr_table_entries = roundup_pow_of_two(nr_table_entries + 1);
 	lopt_size += nr_table_entries * sizeof(struct request_sock *);
-	if (lopt_size > PAGE_SIZE)
-		lopt = vzalloc(lopt_size);
-	else
-		lopt = kzalloc(lopt_size, GFP_KERNEL);
-	if (lopt == NULL)
-		return -ENOMEM;
 
-	for (lopt->max_qlen_log = 3;
-	     (1 << lopt->max_qlen_log) < nr_table_entries;
-	     lopt->max_qlen_log++);
+	if (lopt_size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER))
+		lopt = kzalloc(lopt_size, GFP_KERNEL |
+					  __GFP_NOWARN |
+					  __GFP_NORETRY);
+	if (!lopt)
+		lopt = vzalloc(lopt_size);
+	if (!lopt)
+		return -ENOMEM;
 
 	get_random_bytes(&lopt->hash_rnd, sizeof(lopt->hash_rnd));
 	rwlock_init(&queue->syn_wait_lock);
 	queue->rskq_accept_head = NULL;
 	lopt->nr_table_entries = nr_table_entries;
+	lopt->max_qlen_log = ilog2(nr_table_entries);
 
 	write_lock_bh(&queue->syn_wait_lock);
 	queue->listen_opt = lopt;
@@ -72,22 +72,8 @@
 
 void __reqsk_queue_destroy(struct request_sock_queue *queue)
 {
-	struct listen_sock *lopt;
-	size_t lopt_size;
-
-	/*
-	 * this is an error recovery path only
-	 * no locking needed and the lopt is not NULL
-	 */
-
-	lopt = queue->listen_opt;
-	lopt_size = sizeof(struct listen_sock) +
-		lopt->nr_table_entries * sizeof(struct request_sock *);
-
-	if (lopt_size > PAGE_SIZE)
-		vfree(lopt);
-	else
-		kfree(lopt);
+	/* This is an error recovery path only, no locking needed */
+	kvfree(queue->listen_opt);
 }
 
 static inline struct listen_sock *reqsk_queue_yank_listen_sk(
@@ -107,8 +93,6 @@
 {
 	/* make all the listen_opt local to us */
 	struct listen_sock *lopt = reqsk_queue_yank_listen_sk(queue);
-	size_t lopt_size = sizeof(struct listen_sock) +
-		lopt->nr_table_entries * sizeof(struct request_sock *);
 
 	if (lopt->qlen != 0) {
 		unsigned int i;
@@ -125,10 +109,7 @@
 	}
 
 	WARN_ON(lopt->qlen != 0);
-	if (lopt_size > PAGE_SIZE)
-		vfree(lopt);
-	else
-		kfree(lopt);
+	kvfree(lopt);
 }
 
 /*