diff options
| author | Jakub Kicinski <kuba@kernel.org> | 2022-07-08 04:03:09 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-07-09 04:38:44 +0300 |
| commit | 2d91ecace6614cf6254001566292b808d7f70a91 (patch) | |
| tree | 102051f148bc0998d65f0e2f15c3756eb3bf67ae | |
| parent | 67d7ebdeb2d5a058dd5079107505fffe7332b27a (diff) | |
| download | linux-2d91ecace6614cf6254001566292b808d7f70a91.tar.xz | |
strparser: pad sk_skb_cb to avoid straddling cachelines
sk_skb_cb lives within skb->cb[]. skb->cb[] straddles
2 cache lines, each containing 24B of data.
The first cache line does not contain much interesting
information for users of strparser, so pad things a little.
Previously strp_msg->full_len would live in the first cache
line and strp_msg->offset in the second.
We need to reorder the 8 byte temp_reg with struct tls_msg
to prevent a 4B hole which would push the struct over 48B.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | include/net/strparser.h | 12 | ||||
| -rw-r--r-- | net/strparser/strparser.c | 3 |
2 files changed, 11 insertions, 4 deletions
diff --git a/include/net/strparser.h b/include/net/strparser.h index a191486eb1e4..88900b05443e 100644 --- a/include/net/strparser.h +++ b/include/net/strparser.h @@ -65,15 +65,19 @@ struct _strp_msg { struct sk_skb_cb { #define SK_SKB_CB_PRIV_LEN 20 unsigned char data[SK_SKB_CB_PRIV_LEN]; + /* align strp on cache line boundary within skb->cb[] */ + unsigned char pad[4]; struct _strp_msg strp; - /* temp_reg is a temporary register used for bpf_convert_data_end_access - * when dst_reg == src_reg. - */ - u64 temp_reg; + + /* strp users' data follows */ struct tls_msg { u8 control; u8 decrypted; } tls; + /* temp_reg is a temporary register used for bpf_convert_data_end_access + * when dst_reg == src_reg. + */ + u64 temp_reg; }; static inline struct strp_msg *strp_msg(struct sk_buff *skb) diff --git a/net/strparser/strparser.c b/net/strparser/strparser.c index 1a72c67afed5..8299ceb3e373 100644 --- a/net/strparser/strparser.c +++ b/net/strparser/strparser.c @@ -533,6 +533,9 @@ EXPORT_SYMBOL_GPL(strp_check_rcv); static int __init strp_dev_init(void) { + BUILD_BUG_ON(sizeof(struct sk_skb_cb) > + sizeof_field(struct sk_buff, cb)); + strp_wq = create_singlethread_workqueue("kstrp"); if (unlikely(!strp_wq)) return -ENOMEM; |