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author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2022-06-21 10:19:10 -0700 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2022-06-22 12:59:43 +0100 |
commit | b6e811383062f88212082714db849127fa95142c (patch) | |
tree | 5999695ff674144ba8e4ec4199c30015203fcecf /include | |
parent | f302d180c6d430ea99643b9b2b3407aedaa36703 (diff) | |
download | linux-stable-b6e811383062f88212082714db849127fa95142c.tar.gz linux-stable-b6e811383062f88212082714db849127fa95142c.tar.bz2 linux-stable-b6e811383062f88212082714db849127fa95142c.zip |
af_unix: Define a per-netns hash table.
This commit adds a per netns hash table for AF_UNIX, which size is fixed
as UNIX_HASH_SIZE for now.
The first implementation defines a per-netns hash table as a single array
of lock and list:
struct unix_hashbucket {
spinlock_t lock;
struct hlist_head head;
};
struct netns_unix {
struct unix_hashbucket *hash;
...
};
But, Eric pointed out memory cost that the structure has holes because of
sizeof(spinlock_t), which is 4 (or more if LOCKDEP is enabled). [0] It
could be expensive on a host with thousands of netns and few AF_UNIX
sockets. For this reason, a per-netns hash table uses two dense arrays.
struct unix_table {
spinlock_t *locks;
struct hlist_head *buckets;
};
struct netns_unix {
struct unix_table table;
...
};
Note the length of the list has a significant impact rather than lock
contention, so having shared locks can be an option. But, per-netns
locks and lists still perform better than the global locks and per-netns
lists. [1]
Also, this patch adds a change so that struct netns_unix disappears from
struct net if CONFIG_UNIX is disabled.
[0]: https://lore.kernel.org/netdev/CANn89iLVxO5aqx16azNU7p7Z-nz5NrnM5QTqOzueVxEnkVTxyg@mail.gmail.com/
[1]: https://lore.kernel.org/netdev/20220617175215.1769-1-kuniyu@amazon.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r-- | include/net/net_namespace.h | 2 | ||||
-rw-r--r-- | include/net/netns/unix.h | 6 |
2 files changed, 8 insertions, 0 deletions
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index c4f5601f6e32..20a2992901c2 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -120,7 +120,9 @@ struct net { struct netns_core core; struct netns_mib mib; struct netns_packet packet; +#if IS_ENABLED(CONFIG_UNIX) struct netns_unix unx; +#endif struct netns_nexthop nexthop; struct netns_ipv4 ipv4; #if IS_ENABLED(CONFIG_IPV6) diff --git a/include/net/netns/unix.h b/include/net/netns/unix.h index 91a3d7e39198..6f1a33df061d 100644 --- a/include/net/netns/unix.h +++ b/include/net/netns/unix.h @@ -5,8 +5,14 @@ #ifndef __NETNS_UNIX_H__ #define __NETNS_UNIX_H__ +struct unix_table { + spinlock_t *locks; + struct hlist_head *buckets; +}; + struct ctl_table_header; struct netns_unix { + struct unix_table table; int sysctl_max_dgram_qlen; struct ctl_table_header *ctl; }; |