@@ -66,6 +66,7 @@ static inline struct fq_skb_cb *fq_skb_cb(struct sk_buff *skb)
* in linear list (head,tail), otherwise are placed in a rbtree (t_root).
*/
struct fq_flow {
+/* First cache line : used in fq_gc(), fq_enqueue(), fq_dequeue() */
struct rb_root t_root;
struct sk_buff *head; /* list of skbs for this flow : first skb */
union {
@@ -74,14 +75,18 @@ struct fq_flow {
};
struct rb_node fq_node; /* anchor in fq_root[] trees */
struct sock *sk;
+ u32 socket_hash; /* sk_hash */
int qlen; /* number of packets in flow queue */
+
+/* Second cache line, used in fq_dequeue() */
int credit;
- u32 socket_hash; /* sk_hash */
+ /* 32bit hole on 64bit arches */
+
struct fq_flow *next; /* next pointer in RR lists */
struct rb_node rate_node; /* anchor in q->delayed tree */
u64 time_next_packet;
-};
+} ____cacheline_aligned_in_smp;
struct fq_flow_head {
struct fq_flow *first;
sizeof(struct fq_flow) is 112 bytes on 64bit arches. This means that half of them use two cache lines, but 50% use three cache lines. This patch adds cache line alignment, and makes sure that only the first cache line is touched by fq_enqueue(), which is more expensive that fq_dequeue() in general. Signed-off-by: Eric Dumazet <edumazet@google.com> --- net/sched/sch_fq.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)