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-rw-r--r--Documentation/admin-guide/sysctl/net.rst105
1 files changed, 85 insertions, 20 deletions
diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst
index 287b98708a40..6394f5dc2303 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
============================================
@@ -64,15 +65,16 @@ two flavors of JITs, the newer eBPF JIT currently supported on:
- arm64
- arm32
- ppc64
+ - ppc32
- sparc64
- mips64
- s390x
- - riscv
+ - riscv64
+ - riscv32
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
@@ -100,6 +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
----------------
@@ -270,7 +275,7 @@ 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
@@ -310,6 +315,25 @@ 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
----------
@@ -320,11 +344,20 @@ 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)
@@ -338,10 +371,42 @@ 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 listening 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
----------------------------------------------------------
@@ -352,8 +417,8 @@ 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