From:   Eric Dumazet <redacted>
Date:   Wed, 7 Sep 2022 16:45:17 -0700

On 9/6/22 17:55, Kuniyuki Iwashima wrote:

quoted

The more sockets we have in the hash table, the longer we spend looking
up the socket.  While running a number of small workloads on the same
host, they penalise each other and cause performance degradation.


+
+struct inet_hashinfo *inet_pernet_hashinfo_alloc(struct inet_hashinfo *hashinfo,
+						 unsigned int ehash_entries)
+{
+	struct inet_hashinfo *new_hashinfo;
+	int i;
+
+	new_hashinfo = kmalloc(sizeof(*new_hashinfo), GFP_KERNEL);

You probably could use kmemdup(hashinfo, sizeof(*hashinfo), GFP_KERNEL);

Exactly, I'll use it and remove the manual copy.
Thank you!

quoted

+	if (!new_hashinfo)
+		goto err;
+
+	new_hashinfo->ehash = kvmalloc_array(ehash_entries,
+					     sizeof(struct inet_ehash_bucket),
+					     GFP_KERNEL_ACCOUNT);
+	if (!new_hashinfo->ehash)
+		goto free_hashinfo;
+
+	new_hashinfo->ehash_mask = ehash_entries - 1;
+
+	if (inet_ehash_locks_alloc(new_hashinfo))
+		goto free_ehash;
+
+	for (i = 0; i < ehash_entries; i++)
+		INIT_HLIST_NULLS_HEAD(&new_hashinfo->ehash[i].chain, i);
+
+	new_hashinfo->bind_bucket_cachep = hashinfo->bind_bucket_cachep;
+	new_hashinfo->bhash = hashinfo->bhash;
+	new_hashinfo->bind2_bucket_cachep = hashinfo->bind2_bucket_cachep;
+	new_hashinfo->bhash2 = hashinfo->bhash2;
+	new_hashinfo->bhash_size = hashinfo->bhash_size;
+
+	new_hashinfo->lhash2_mask = hashinfo->lhash2_mask;
+	new_hashinfo->lhash2 = hashinfo->lhash2;

This would avoid copying all these @hashinfo fields.