[PATCH v4 8/8] ipvs: optimize the use of flags in ip_vs_bind_dest

[Julian Anastasov <ja@xxxxxx>]

        cp->flags is marked volatile but ip_vs_bind_dest
can safely modify the flags, so save some CPU cycles by
using temp variable.

Signed-off-by: Julian Anastasov <ja@xxxxxx>
---
 net/netfilter/ipvs/ip_vs_conn.c |   15 +++++++++------
 1 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c
index 6a43c93..7f21b91 100644
--- a/net/netfilter/ipvs/ip_vs_conn.c
+++ b/net/netfilter/ipvs/ip_vs_conn.c
@@ -548,6 +548,7 @@ static inline void
 ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest)
 {
        unsigned int conn_flags;
+       __u32 flags;
 
        /* if dest is NULL, then return directly */
        if (!dest)
@@ -559,17 +560,19 @@ ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest 
*dest)
        conn_flags = atomic_read(&dest->conn_flags);
        if (cp->protocol != IPPROTO_UDP)
                conn_flags &= ~IP_VS_CONN_F_ONE_PACKET;
+       flags = cp->flags;
        /* Bind with the destination and its corresponding transmitter */
-       if (cp->flags & IP_VS_CONN_F_SYNC) {
+       if (flags & IP_VS_CONN_F_SYNC) {
                /* if the connection is not template and is created
                 * by sync, preserve the activity flag.
                 */
-               if (!(cp->flags & IP_VS_CONN_F_TEMPLATE))
+               if (!(flags & IP_VS_CONN_F_TEMPLATE))
                        conn_flags &= ~IP_VS_CONN_F_INACTIVE;
                /* connections inherit forwarding method from dest */
-               cp->flags &= ~(IP_VS_CONN_F_FWD_MASK | IP_VS_CONN_F_NOOUTPUT);
+               flags &= ~(IP_VS_CONN_F_FWD_MASK | IP_VS_CONN_F_NOOUTPUT);
        }
-       cp->flags |= conn_flags;
+       flags |= conn_flags;
+       cp->flags = flags;
        cp->dest = dest;
 
        IP_VS_DBG_BUF(7, "Bind-dest %s c:%s:%d v:%s:%d "
@@ -584,11 +587,11 @@ ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest 
*dest)
                      atomic_read(&dest->refcnt));
 
        /* Update the connection counters */
-       if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
+       if (!(flags & IP_VS_CONN_F_TEMPLATE)) {
                /* It is a normal connection, so modify the counters
                 * according to the flags, later the protocol can
                 * update them on state change */
-               if (!(cp->flags & IP_VS_CONN_F_INACTIVE))
+               if (!(flags & IP_VS_CONN_F_INACTIVE))
                        atomic_inc(&dest->activeconns);
                else
                        atomic_inc(&dest->inactconns);
-- 
1.7.3.4

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