Re: [PATCH 5.10 076/124] tcp: convert elligible sysctls to u8

Greg,

On Tue, Apr 18, 2023 at 02:21:35PM +0200, Greg Kroah-Hartman wrote:

From: Eric Dumazet edumazet@google.com

[ Upstream commit 4ecc1baf362c5df2dcabe242511e38ee28486545 ]

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.

This commit in 5.10 needs fix from d24f511b04b8 ("tcp: fix tcp_min_tso_segs sysctl") which have incorrectly set commit id in Fixes tag. (Perhaps, that's why it's missed.)

Fixes: 47996b489bdc ("tcp: convert elligible sysctls to u8")

Thanks,

Signed-off-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Stable-dep-of: dc5110c2d959 ("tcp: restrict net.ipv4.tcp_app_win") Signed-off-by: Sasha Levin sashal@kernel.org

---

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 92e3d8fe954ab..d8b320cf54ba0 100644 --- a/include/net/netns/ipv4.h +++ b/include/net/netns/ipv4.h @@ -114,11 +114,11 @@ 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;

@@ -126,46 +126,47 @@ 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;

@@ -183,7 +184,6 @@ 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 cb587bdd683a6..1a2506f795d4e 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -720,17 +720,17 @@ 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, },

@@ -738,9 +738,9 @@ 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",

@@ -842,9 +842,9 @@ 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",

@@ -856,26 +856,26 @@ 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 { @@ -888,24 +888,24 @@ 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",

@@ -924,9 +924,9 @@ 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, },

@@ -1012,88 +1012,88 @@ 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",

@@ -1105,16 +1105,16 @@ 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",

@@ -1128,46 +1128,46 @@ 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",

@@ -1186,9 +1186,9 @@ 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, },

@@ -1204,9 +1204,9 @@ 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, },

@@ -1277,9 +1277,9 @@ 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, },

-- 2.39.2