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 48fd356..f528d1b 100644
--- a/include/net/inet_timewait_sock.h
+++ b/include/net/inet_timewait_sock.h
@@ -58,6 +58,11 @@
# 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 @@
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 5f64875..2200027 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -222,7 +222,7 @@
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 @@
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 @@
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 1f27c9f..9bcd8f7 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -387,11 +387,11 @@
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 5c71501..dde8bad 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1811,7 +1811,7 @@
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;
