diff options
| author | Li RongQing <lirongqing@baidu.com> | 2018-12-06 16:08:17 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-12-06 12:15:27 -0800 |
| commit | 83b1bc122cab87547731a154db5feec5b9d4807c (patch) | |
| tree | d338b04983991a80cc807a0d01282f05076a65d1 /drivers/net | |
| parent | 7a35a50df5a34e6eaee1b1f4f913b84879068fee (diff) | |
| download | linux-83b1bc122cab87547731a154db5feec5b9d4807c.tar.gz | |
tun: align write-heavy flow entry members to a cache line
tun flow entry 'updated' fields are written when receive every packet. Thus if a flow is receiving packets from a particular flow entry, it'll cause false-sharing with all the other who has looked it up, so move it in its own cache line and update 'queue_index' and 'update' field only when they are changed to reduce the cache false-sharing. Signed-off-by: Zhang Yu <zhangyu31@baidu.com> Signed-off-by: Wang Li <wangli39@baidu.com> Signed-off-by: Li RongQing <lirongqing@baidu.com> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/tun.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 835c73f42ae7..d0745dc81976 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -201,7 +201,7 @@ struct tun_flow_entry { u32 rxhash; u32 rps_rxhash; int queue_index; - unsigned long updated; + unsigned long updated ____cacheline_aligned_in_smp; }; #define TUN_NUM_FLOW_ENTRIES 1024 @@ -539,8 +539,10 @@ static void tun_flow_update(struct tun_struct *tun, u32 rxhash, e = tun_flow_find(head, rxhash); if (likely(e)) { /* TODO: keep queueing to old queue until it's empty? */ - e->queue_index = queue_index; - e->updated = jiffies; + if (e->queue_index != queue_index) + e->queue_index = queue_index; + if (e->updated != jiffies) + e->updated = jiffies; sock_rps_record_flow_hash(e->rps_rxhash); } else { spin_lock_bh(&tun->lock); |