From: Eric Dumazet <eduma...@google.com>
Many tcp sysctls are either bools or small ints that can fit into u8.
Reducing space taken by sysctls can save few cache line misses
when sending/receiving data while cpu caches are empty,
for example after cpu idle period.
This is hard to measure with typical network performance tests,
but after this patch, struct netns_ipv4 has shrunk
by three cache lines.
Signed-off-by: Eric Dumazet <eduma...@google.com>
---
include/net/netns/ipv4.h | 68 +++++++++----------
net/ipv4/sysctl_net_ipv4.c | 136 ++++++++++++++++++-------------------
2 files changed, 102 insertions(+), 102 deletions(-)
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index
00f250ee441973586198014df8791c60ae298565..d377266d133f076eda7d0469da75d5f7ee1431b9
100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -113,11 +113,11 @@ struct netns_ipv4 {
u8 sysctl_nexthop_compat_mode;
u8 sysctl_fwmark_reflect;
- int sysctl_tcp_fwmark_accept;
+ u8 sysctl_tcp_fwmark_accept;
#ifdef CONFIG_NET_L3_MASTER_DEV
- int sysctl_tcp_l3mdev_accept;
+ u8 sysctl_tcp_l3mdev_accept;
#endif
- int sysctl_tcp_mtu_probing;
+ u8 sysctl_tcp_mtu_probing;
int sysctl_tcp_mtu_probe_floor;
int sysctl_tcp_base_mss;
int sysctl_tcp_min_snd_mss;
@@ -125,46 +125,47 @@ struct netns_ipv4 {
u32 sysctl_tcp_probe_interval;
int sysctl_tcp_keepalive_time;
- int sysctl_tcp_keepalive_probes;
int sysctl_tcp_keepalive_intvl;
+ u8 sysctl_tcp_keepalive_probes;
- int sysctl_tcp_syn_retries;
- int sysctl_tcp_synack_retries;
- int sysctl_tcp_syncookies;
+ u8 sysctl_tcp_syn_retries;
+ u8 sysctl_tcp_synack_retries;
+ u8 sysctl_tcp_syncookies;
int sysctl_tcp_reordering;
- int sysctl_tcp_retries1;
- int sysctl_tcp_retries2;
- int sysctl_tcp_orphan_retries;
+ u8 sysctl_tcp_retries1;
+ u8 sysctl_tcp_retries2;
+ u8 sysctl_tcp_orphan_retries;
+ u8 sysctl_tcp_tw_reuse;
int sysctl_tcp_fin_timeout;
unsigned int sysctl_tcp_notsent_lowat;
- int sysctl_tcp_tw_reuse;
- int sysctl_tcp_sack;
- int sysctl_tcp_window_scaling;
- int sysctl_tcp_timestamps;
- int sysctl_tcp_early_retrans;
- int sysctl_tcp_recovery;
- int sysctl_tcp_thin_linear_timeouts;
- int sysctl_tcp_slow_start_after_idle;
- int sysctl_tcp_retrans_collapse;
- int sysctl_tcp_stdurg;
- int sysctl_tcp_rfc1337;
- int sysctl_tcp_abort_on_overflow;
- int sysctl_tcp_fack;
+ u8 sysctl_tcp_sack;
+ u8 sysctl_tcp_window_scaling;
+ u8 sysctl_tcp_timestamps;
+ u8 sysctl_tcp_early_retrans;
+ u8 sysctl_tcp_recovery;
+ u8 sysctl_tcp_thin_linear_timeouts;
+ u8 sysctl_tcp_slow_start_after_idle;
+ u8 sysctl_tcp_retrans_collapse;
+ u8 sysctl_tcp_stdurg;
+ u8 sysctl_tcp_rfc1337;
+ u8 sysctl_tcp_abort_on_overflow;
+ u8 sysctl_tcp_fack; /* obsolete */
int sysctl_tcp_max_reordering;
- int sysctl_tcp_dsack;
- int sysctl_tcp_app_win;
int sysctl_tcp_adv_win_scale;
- int sysctl_tcp_frto;
- int sysctl_tcp_nometrics_save;
- int sysctl_tcp_no_ssthresh_metrics_save;
- int sysctl_tcp_moderate_rcvbuf;
- int sysctl_tcp_tso_win_divisor;
- int sysctl_tcp_workaround_signed_windows;
+ u8 sysctl_tcp_dsack;
+ u8 sysctl_tcp_app_win;
+ u8 sysctl_tcp_frto;
+ u8 sysctl_tcp_nometrics_save;
+ u8 sysctl_tcp_no_ssthresh_metrics_save;
+ u8 sysctl_tcp_moderate_rcvbuf;
+ u8 sysctl_tcp_tso_win_divisor;
+ u8 sysctl_tcp_workaround_signed_windows;
int sysctl_tcp_limit_output_bytes;
int sysctl_tcp_challenge_ack_limit;
- int sysctl_tcp_min_tso_segs;
int sysctl_tcp_min_rtt_wlen;
- int sysctl_tcp_autocorking;
+ u8 sysctl_tcp_min_tso_segs;
+ u8 sysctl_tcp_autocorking;
+ u8 sysctl_tcp_reflect_tos;
int sysctl_tcp_invalid_ratelimit;
int sysctl_tcp_pacing_ss_ratio;
int sysctl_tcp_pacing_ca_ratio;
@@ -182,7 +183,6 @@ struct netns_ipv4 {
unsigned int sysctl_tcp_fastopen_blackhole_timeout;
atomic_t tfo_active_disable_times;
unsigned long tfo_active_disable_stamp;
- int sysctl_tcp_reflect_tos;
int sysctl_udp_wmem_min;
int sysctl_udp_rmem_min;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index
510a326356127c0a822f9a1215737a5c843fd58c..442ff4be1bde236563b6cfea67179de4f30856bf
100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -775,17 +775,17 @@ static struct ctl_table ipv4_net_table[] = {
{
.procname = "tcp_fwmark_accept",
.data = &init_net.ipv4.sysctl_tcp_fwmark_accept,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dou8vec_minmax,
},
#ifdef CONFIG_NET_L3_MASTER_DEV
{
.procname = "tcp_l3mdev_accept",
.data = &init_net.ipv4.sysctl_tcp_l3mdev_accept,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
+ .proc_handler = proc_dou8vec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
@@ -793,9 +793,9 @@ static struct ctl_table ipv4_net_table[] = {
{
.procname = "tcp_mtu_probing",
.data = &init_net.ipv4.sysctl_tcp_mtu_probing,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_base_mss",
@@ -897,9 +897,9 @@ static struct ctl_table ipv4_net_table[] = {
{
.procname = "tcp_keepalive_probes",
.data = &init_net.ipv4.sysctl_tcp_keepalive_probes,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_keepalive_intvl",
@@ -911,26 +911,26 @@ static struct ctl_table ipv4_net_table[] = {
{
.procname = "tcp_syn_retries",
.data = &init_net.ipv4.sysctl_tcp_syn_retries,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
+ .proc_handler = proc_dou8vec_minmax,
.extra1 = &tcp_syn_retries_min,
.extra2 = &tcp_syn_retries_max
},
{
.procname = "tcp_synack_retries",
.data = &init_net.ipv4.sysctl_tcp_synack_retries,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
#ifdef CONFIG_SYN_COOKIES
{
.procname = "tcp_syncookies",
.data = &init_net.ipv4.sysctl_tcp_syncookies,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
#endif
{
@@ -943,24 +943,24 @@ static struct ctl_table ipv4_net_table[] = {
{
.procname = "tcp_retries1",
.data = &init_net.ipv4.sysctl_tcp_retries1,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
+ .proc_handler = proc_dou8vec_minmax,
.extra2 = &tcp_retr1_max
},
{
.procname = "tcp_retries2",
.data = &init_net.ipv4.sysctl_tcp_retries2,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_orphan_retries",
.data = &init_net.ipv4.sysctl_tcp_orphan_retries,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_fin_timeout",
@@ -979,9 +979,9 @@ static struct ctl_table ipv4_net_table[] = {
{
.procname = "tcp_tw_reuse",
.data = &init_net.ipv4.sysctl_tcp_tw_reuse,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
+ .proc_handler = proc_dou8vec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = &two,
},
@@ -1067,88 +1067,88 @@ static struct ctl_table ipv4_net_table[] = {
{
.procname = "tcp_sack",
.data = &init_net.ipv4.sysctl_tcp_sack,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_window_scaling",
.data = &init_net.ipv4.sysctl_tcp_window_scaling,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_timestamps",
.data = &init_net.ipv4.sysctl_tcp_timestamps,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_early_retrans",
.data = &init_net.ipv4.sysctl_tcp_early_retrans,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
+ .proc_handler = proc_dou8vec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = &four,
},
{
.procname = "tcp_recovery",
.data = &init_net.ipv4.sysctl_tcp_recovery,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_thin_linear_timeouts",
.data =
&init_net.ipv4.sysctl_tcp_thin_linear_timeouts,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_slow_start_after_idle",
.data =
&init_net.ipv4.sysctl_tcp_slow_start_after_idle,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_retrans_collapse",
.data = &init_net.ipv4.sysctl_tcp_retrans_collapse,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_stdurg",
.data = &init_net.ipv4.sysctl_tcp_stdurg,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_rfc1337",
.data = &init_net.ipv4.sysctl_tcp_rfc1337,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_abort_on_overflow",
.data = &init_net.ipv4.sysctl_tcp_abort_on_overflow,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_fack",
.data = &init_net.ipv4.sysctl_tcp_fack,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_max_reordering",
@@ -1160,16 +1160,16 @@ static struct ctl_table ipv4_net_table[] = {
{
.procname = "tcp_dsack",
.data = &init_net.ipv4.sysctl_tcp_dsack,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_app_win",
.data = &init_net.ipv4.sysctl_tcp_app_win,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_adv_win_scale",
@@ -1183,46 +1183,46 @@ static struct ctl_table ipv4_net_table[] = {
{
.procname = "tcp_frto",
.data = &init_net.ipv4.sysctl_tcp_frto,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_no_metrics_save",
.data = &init_net.ipv4.sysctl_tcp_nometrics_save,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_no_ssthresh_metrics_save",
.data =
&init_net.ipv4.sysctl_tcp_no_ssthresh_metrics_save,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
+ .proc_handler = proc_dou8vec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
{
.procname = "tcp_moderate_rcvbuf",
.data = &init_net.ipv4.sysctl_tcp_moderate_rcvbuf,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_tso_win_divisor",
.data = &init_net.ipv4.sysctl_tcp_tso_win_divisor,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_workaround_signed_windows",
.data =
&init_net.ipv4.sysctl_tcp_workaround_signed_windows,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .proc_handler = proc_dou8vec_minmax,
},
{
.procname = "tcp_limit_output_bytes",
@@ -1241,9 +1241,9 @@ static struct ctl_table ipv4_net_table[] = {
{
.procname = "tcp_min_tso_segs",
.data = &init_net.ipv4.sysctl_tcp_min_tso_segs,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
+ .proc_handler = proc_dou8vec_minmax,
.extra1 = SYSCTL_ONE,
.extra2 = &gso_max_segs,
},
@@ -1259,9 +1259,9 @@ static struct ctl_table ipv4_net_table[] = {
{
.procname = "tcp_autocorking",
.data = &init_net.ipv4.sysctl_tcp_autocorking,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
+ .proc_handler = proc_dou8vec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
@@ -1332,9 +1332,9 @@ static struct ctl_table ipv4_net_table[] = {
{
.procname = "tcp_reflect_tos",
.data = &init_net.ipv4.sysctl_tcp_reflect_tos,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(u8),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
+ .proc_handler = proc_dou8vec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
--
2.31.0.291.g576ba9dcdaf-goog
