diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-08-19 17:40:30 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-08-20 19:35:00 -0700 |
| commit | a6d4f25888b83b8300aef28d9ee22765c1cc9b34 (patch) | |
| tree | 7c3b8fa06aae808d41f420cd309547133676f844 /Documentation | |
| parent | 2a2e6e53756fe476f8e3237fc66e37d5431757cf (diff) | |
net: set net.core.rmem_max and net.core.wmem_max to 4 MB
SO_RCVBUF and SO_SNDBUF have limited range today, unless
distros or system admins change rmem_max and wmem_max.
Even iproute2 uses 1 MB SO_RCVBUF which is capped by
the kernel.
Decouple [rw]mem_max and [rw]mem_default and increase
[rw]mem_max to 4 MB.
Before:
$ sysctl net.core.rmem_default net.core.rmem_max net.core.wmem_default net.core.wmem_max
net.core.rmem_default = 212992
net.core.rmem_max = 212992
net.core.wmem_default = 212992
net.core.wmem_max = 212992
After:
$ sysctl net.core.rmem_default net.core.rmem_max net.core.wmem_default net.core.wmem_max
net.core.rmem_default = 212992
net.core.rmem_max = 4194304
net.core.wmem_default = 212992
net.core.wmem_max = 4194304
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20250819174030.1986278-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/sysctl/net.rst | 4 | ||||
| -rw-r--r-- | Documentation/networking/ip-sysctl.rst | 6 |
2 files changed, 7 insertions, 3 deletions
diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst index 7b0c4291c686..2ef50828aff1 100644 --- a/Documentation/admin-guide/sysctl/net.rst +++ b/Documentation/admin-guide/sysctl/net.rst @@ -222,6 +222,8 @@ rmem_max The maximum receive socket buffer size in bytes. +Default: 4194304 + rps_default_mask ---------------- @@ -247,6 +249,8 @@ wmem_max The maximum send socket buffer size in bytes. +Default: 4194304 + message_burst and message_cost ------------------------------ diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index 43badb338d22..9f5891c9b07b 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -209,7 +209,7 @@ neigh/default/unres_qlen_bytes - INTEGER Setting negative value is meaningless and will return error. - Default: SK_WMEM_MAX, (same as net.core.wmem_default). + Default: SK_WMEM_DEFAULT, (same as net.core.wmem_default). Exact value depends on architecture and kernel options, but should be enough to allow queuing 256 packets @@ -805,8 +805,8 @@ tcp_rmem - vector of 3 INTEGERs: min, default, max This value results in initial window of 65535. max: maximal size of receive buffer allowed for automatically - selected receiver buffers for TCP socket. This value does not override - net.core.rmem_max. Calling setsockopt() with SO_RCVBUF disables + selected receiver buffers for TCP socket. + Calling setsockopt() with SO_RCVBUF disables automatic tuning of that socket's receive buffer size, in which case this value is ignored. Default: between 131072 and 32MB, depending on RAM size. |