tcp: shrink tcp6_timewait_sock by one cache line

While working on tcp listener refactoring, I found that it
would really make things easier if sock_common could include
the IPv6 addresses needed in the lookups, instead of doing
very complex games to get their values (depending on sock
being SYN_RECV, ESTABLISHED, TIME_WAIT)

For this to happen, I need to be sure that tcp6_timewait_sock
and tcp_timewait_sock consume same number of cache lines.

This is possible if we only use 32bits for tw_ttd, as we remove
one 32bit hole in inet_timewait_sock

inet_tw_time_stamp() is defined and used, even if its current
implementation looks like tcp_time_stamp : We might need finer
resolution for tcp_time_stamp in the future.

Before patch : sizeof(struct tcp6_timewait_sock) = 0xc8

After patch : sizeof(struct tcp6_timewait_sock) = 0xc0

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/inet_timewait_sock.h b/include/net/inet_timewait_sock.h
index 48fd3561722c5bb81dd3cfd3d07adf037bf5e87d..f528d1b0ac951bba9c247a28f1955d2693ee6138 100644 (file)
--- a/include/net/inet_timewait_sock.h
+++ b/include/net/inet_timewait_sock.h
@@ -58,6 +58,11 @@ struct inet_hashinfo;
 # define INET_TWDR_RECYCLE_TICK (12 + 2 - INET_TWDR_RECYCLE_SLOTS_LOG)
 #endif
 
+static inline u32 inet_tw_time_stamp(void)
+{
+       return jiffies;
+}
+
 /* TIME_WAIT reaping mechanism. */
 #define INET_TWDR_TWKILL_SLOTS 8 /* Please keep this a power of 2. */
 
@@ -130,7 +135,7 @@ struct inet_timewait_sock {
                                tw_tos          : 8,
                                tw_ipv6_offset  : 16;
        kmemcheck_bitfield_end(flags);
-       unsigned long           tw_ttd;
+       u32                     tw_ttd;
        struct inet_bind_bucket *tw_tb;
        struct hlist_node       tw_death_node;
 };

diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 5f648751fce2d03418f4a6425c7ba0dbfb3ddfc0..22000279efc89685ea0aab1128ec8cc990e4a784 100644 (file)
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -222,7 +222,7 @@ static int inet_twsk_diag_fill(struct inet_timewait_sock *tw,
                               u32 portid, u32 seq, u16 nlmsg_flags,
                               const struct nlmsghdr *unlh)
 {
-       long tmo;
+       s32 tmo;
        struct inet_diag_msg *r;
        struct nlmsghdr *nlh;
 
@@ -234,7 +234,7 @@ static int inet_twsk_diag_fill(struct inet_timewait_sock *tw,
        r = nlmsg_data(nlh);
        BUG_ON(tw->tw_state != TCP_TIME_WAIT);
 
-       tmo = tw->tw_ttd - jiffies;
+       tmo = tw->tw_ttd - inet_tw_time_stamp();
        if (tmo < 0)
                tmo = 0;
 
@@ -248,7 +248,7 @@ static int inet_twsk_diag_fill(struct inet_timewait_sock *tw,
        r->id.idiag_dst[0]    = tw->tw_daddr;
        r->idiag_state        = tw->tw_substate;
        r->idiag_timer        = 3;
-       r->idiag_expires      = DIV_ROUND_UP(tmo * 1000, HZ);
+       r->idiag_expires      = jiffies_to_msecs(tmo);
        r->idiag_rqueue       = 0;
        r->idiag_wqueue       = 0;
        r->idiag_uid          = 0;

diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 1f27c9f4afd07fbf55589ed4e6e730375dcdc0a3..9bcd8f7234ec4755235e7940377119a1c832c80d 100644 (file)
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -387,11 +387,11 @@ void inet_twsk_schedule(struct inet_timewait_sock *tw,
                        if (slot >= INET_TWDR_TWKILL_SLOTS)
                                slot = INET_TWDR_TWKILL_SLOTS - 1;
                }
-               tw->tw_ttd = jiffies + timeo;
+               tw->tw_ttd = inet_tw_time_stamp() + timeo;
                slot = (twdr->slot + slot) & (INET_TWDR_TWKILL_SLOTS - 1);
                list = &twdr->cells[slot];
        } else {
-               tw->tw_ttd = jiffies + (slot << INET_TWDR_RECYCLE_TICK);
+               tw->tw_ttd = inet_tw_time_stamp() + (slot << INET_TWDR_RECYCLE_TICK);
 
                if (twdr->twcal_hand < 0) {
                        twdr->twcal_hand = 0;

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 5c71501fc917d6271f72cea50cb98b9ad783f1c4..dde8bad0448178429630e1b739b31a3da04f26a6 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1811,7 +1811,7 @@ static void get_timewait6_sock(struct seq_file *seq,
        const struct in6_addr *dest, *src;
        __u16 destp, srcp;
        const struct inet6_timewait_sock *tw6 = inet6_twsk((struct sock *)tw);
-       long delta = tw->tw_ttd - jiffies;
+       s32 delta = tw->tw_ttd - inet_tw_time_stamp();
 
        dest = &tw6->tw_v6_daddr;
        src  = &tw6->tw_v6_rcv_saddr;