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Diffstat (limited to 'Documentation/admin-guide/sysctl/net.rst')
| -rw-r--r-- | Documentation/admin-guide/sysctl/net.rst | 108 |
1 files changed, 89 insertions, 19 deletions
diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst index e043c9213388..4877563241f3 100644 --- a/Documentation/admin-guide/sysctl/net.rst +++ b/Documentation/admin-guide/sysctl/net.rst @@ -31,17 +31,18 @@ see only some of them, depending on your kernel's configuration. Table : Subdirectories in /proc/sys/net - ========= =================== = ========== ================== + ========= =================== = ========== =================== Directory Content Directory Content - ========= =================== = ========== ================== - core General parameter appletalk Appletalk protocol - unix Unix domain sockets netrom NET/ROM - 802 E802 protocol ax25 AX25 - ethernet Ethernet protocol rose X.25 PLP layer + ========= =================== = ========== =================== + 802 E802 protocol mptcp Multipath TCP + appletalk Appletalk protocol netfilter Network Filter + ax25 AX25 netrom NET/ROM + bridge Bridging rose X.25 PLP layer + core General parameter tipc TIPC + ethernet Ethernet protocol unix Unix domain sockets ipv4 IP version 4 x25 X.25 protocol - bridge Bridging decnet DEC net - ipv6 IP version 6 tipc TIPC - ========= =================== = ========== ================== + ipv6 IP version 6 + ========= =================== = ========== =================== 1. /proc/sys/net/core - Network core options ============================================ @@ -64,6 +65,7 @@ two flavors of JITs, the newer eBPF JIT currently supported on: - arm64 - arm32 - ppc64 + - ppc32 - sparc64 - mips64 - s390x @@ -73,7 +75,6 @@ two flavors of JITs, the newer eBPF JIT currently supported on: And the older cBPF JIT supported on the following archs: - mips - - ppc - sparc eBPF JITs are a superset of cBPF JITs, meaning the kernel will @@ -101,6 +102,9 @@ Values: - 1 - enable JIT hardening for unprivileged users only - 2 - enable JIT hardening for all users +where "privileged user" in this context means a process having +CAP_BPF or CAP_SYS_ADMIN in the root user name space. + bpf_jit_kallsyms ---------------- @@ -211,6 +215,12 @@ rmem_max The maximum receive socket buffer size in bytes. +rps_default_mask +---------------- + +The default RPS CPU mask used on newly created network devices. An empty +mask means RPS disabled by default. + tstamp_allow_data ----------------- Allow processes to receive tx timestamps looped together with the original @@ -271,7 +281,7 @@ poll cycle or the number of packets processed reaches netdev_budget. netdev_max_backlog ------------------ -Maximum number of packets, queued on the INPUT side, when the interface +Maximum number of packets, queued on the INPUT side, when the interface receives packets faster than kernel can process them. netdev_rss_key @@ -311,6 +321,25 @@ permit to distribute the load on several cpus. If set to 1 (default), timestamps are sampled as soon as possible, before queueing. +netdev_unregister_timeout_secs +------------------------------ + +Unregister network device timeout in seconds. +This option controls the timeout (in seconds) used to issue a warning while +waiting for a network device refcount to drop to 0 during device +unregistration. A lower value may be useful during bisection to detect +a leaked reference faster. A larger value may be useful to prevent false +warnings on slow/loaded systems. +Default value is 10, minimum 1, maximum 3600. + +skb_defer_max +------------- + +Max size (in skbs) of the per-cpu list of skbs being freed +by the cpu which allocated them. Used by TCP stack so far. + +Default: 64 + optmem_max ---------- @@ -321,11 +350,20 @@ fb_tunnels_only_for_init_net ---------------------------- Controls if fallback tunnels (like tunl0, gre0, gretap0, erspan0, -sit0, ip6tnl0, ip6gre0) are automatically created when a new -network namespace is created, if corresponding tunnel is present -in initial network namespace. -If set to 1, these devices are not automatically created, and -user space is responsible for creating them if needed. +sit0, ip6tnl0, ip6gre0) are automatically created. There are 3 possibilities +(a) value = 0; respective fallback tunnels are created when module is +loaded in every net namespaces (backward compatible behavior). +(b) value = 1; [kcmd value: initns] respective fallback tunnels are +created only in init net namespace and every other net namespace will +not have them. +(c) value = 2; [kcmd value: none] fallback tunnels are not created +when a module is loaded in any of the net namespace. Setting value to +"2" is pointless after boot if these modules are built-in, so there is +a kernel command-line option that can change this default. Please refer to +Documentation/admin-guide/kernel-parameters.txt for additional details. + +Not creating fallback tunnels gives control to userspace to create +whatever is needed only and avoid creating devices which are redundant. Default : 0 (for compatibility reasons) @@ -339,10 +377,42 @@ settings from init_net and for IPv6 we reset all settings to default. If set to 1, both IPv4 and IPv6 settings are forced to inherit from current ones in init_net. If set to 2, both IPv4 and IPv6 settings are -forced to reset to their default values. +forced to reset to their default values. If set to 3, both IPv4 and IPv6 +settings are forced to inherit from current ones in the netns where this +new netns has been created. Default : 0 (for compatibility reasons) +txrehash +-------- + +Controls default hash rethink behaviour on socket when SO_TXREHASH option is set +to SOCK_TXREHASH_DEFAULT (i. e. not overridden by setsockopt). + +If set to 1 (default), hash rethink is performed on listening socket. +If set to 0, hash rethink is not performed. + +gro_normal_batch +---------------- + +Maximum number of the segments to batch up on output of GRO. When a packet +exits GRO, either as a coalesced superframe or as an original packet which +GRO has decided not to coalesce, it is placed on a per-NAPI list. This +list is then passed to the stack when the number of segments reaches the +gro_normal_batch limit. + +high_order_alloc_disable +------------------------ + +By default the allocator for page frags tries to use high order pages (order-3 +on x86). While the default behavior gives good results in most cases, some users +might have hit a contention in page allocations/freeing. This was especially +true on older kernels (< 5.14) when high-order pages were not stored on per-cpu +lists. This allows to opt-in for order-0 allocation instead but is now mostly of +historical importance. + +Default: 0 + 2. /proc/sys/net/unix - Parameters for Unix domain sockets ---------------------------------------------------------- @@ -353,8 +423,8 @@ socket's buffer. It will not take effect unless PF_UNIX flag is specified. 3. /proc/sys/net/ipv4 - IPV4 settings ------------------------------------- -Please see: Documentation/networking/ip-sysctl.txt and ipvs-sysctl.txt for -descriptions of these entries. +Please see: Documentation/networking/ip-sysctl.rst and +Documentation/admin-guide/sysctl/net.rst for descriptions of these entries. 4. Appletalk |