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net_sched: sch_fq: change fq_flow size/layout

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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>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2020-05-02 19:54:19 -07:00 committed by David S. Miller
parent dde0a648fc
commit 7ba0537c2b
1 changed files with 8 additions and 3 deletions
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11
net/sched/sch_fq.c
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@ -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;
int qlen; /* number of packets in flow queue */
int credit;
u32 socket_hash; /* sk_hash */
int qlen; /* number of packets in flow queue */
/* Second cache line, used in fq_dequeue() */
int credit;
/* 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;