From 45028bdd82ca3f54d8bb0e99330b1bab6e64cb78 Mon Sep 17 00:00:00 2001
From: Fabricio Voznika <fvoznika@google.com>
Date: Tue, 16 Apr 2019 15:44:35 -0700
Subject: Update Linux version requirement for GSO

---
 content/docs/user_guide/FAQ.md        |  4 +++-
 content/docs/user_guide/docker.md     |  4 +++-
 content/docs/user_guide/networking.md | 22 ++++++++++++++++++++++
 content/docs/user_guide/oci.md        |  4 +++-
 4 files changed, 31 insertions(+), 3 deletions(-)

(limited to 'content/docs/user_guide')

diff --git a/content/docs/user_guide/FAQ.md b/content/docs/user_guide/FAQ.md
index da881f171..3226da8b1 100644
--- a/content/docs/user_guide/FAQ.md
+++ b/content/docs/user_guide/FAQ.md
@@ -5,7 +5,7 @@ weight = 1000
 
 ### What operating systems are supported?
 
-gVisor requires Linux {{< required_linux >}}.
+gVisor requires Linux {{< required_linux >}} ([older Linux][old-linux]).
 
 ### What CPU architectures are supported?
 
@@ -57,3 +57,5 @@ directories.
 ### What's the security model?
 
 See the [Security Model](../../architecture_guide/security/).
+
+[old-linux]: /docs/user_guide/networking/#gso
diff --git a/content/docs/user_guide/docker.md b/content/docs/user_guide/docker.md
index 4b8f3acb6..99cb766ff 100644
--- a/content/docs/user_guide/docker.md
+++ b/content/docs/user_guide/docker.md
@@ -7,7 +7,8 @@ gVisor.
 
 ## Install gVisor
 
-> Note: gVisor supports only x86\_64 and requires Linux {{< required_linux >}}.
+> Note: gVisor supports only x86\_64 and requires Linux {{< required_linux >}}
+> ([older Linux][old-linux]).
 
 {{% readfile file="docs/includes/install_gvisor.md" markdown="true" %}}
 
@@ -87,4 +88,5 @@ Next, look at the different options available for gVisor: [platform](../platform
 [network](../networking/), [filesystem](../filesystem/).
 
 [docker]: https://docs.docker.com/install/
+[old-linux]: /docs/user_guide/networking/#gso
 [storage-driver]: https://docs.docker.com/engine/reference/commandline/dockerd/#daemon-storage-driver
diff --git a/content/docs/user_guide/networking.md b/content/docs/user_guide/networking.md
index f1aa77625..92447b3fb 100644
--- a/content/docs/user_guide/networking.md
+++ b/content/docs/user_guide/networking.md
@@ -60,4 +60,26 @@ Add the following `runtimeArgs` to your Docker configuration
 }
 ```
 
+### Disable GSO {#gso}
+
+If your Linux is older than {{< required_linux >}}, you can disable Generic
+Segmentation Offload (GSO) to run with a kernel that is newer than 3.17. Add the
+`--gso=false` flag to your Docker runtime configuration (`/etc/docker/daemon.json`)
+and restart the Docker daemon:
+
+> Note: Network performance, especially for large payloads, will be greatly reduced.
+
+```json
+{
+    "runtimes": {
+        "runsc": {
+            "path": "/usr/local/bin/runsc",
+            "runtimeArgs": [
+                "--gso=false"
+            ]
+       }
+    }
+}
+```
+
 [netstack]: https://github.com/google/netstack
diff --git a/content/docs/user_guide/oci.md b/content/docs/user_guide/oci.md
index cfde696e9..288575fc4 100644
--- a/content/docs/user_guide/oci.md
+++ b/content/docs/user_guide/oci.md
@@ -7,7 +7,8 @@ container using the runtime directly with the default platform.
 
 ## Install gVisor
 
-> Note: gVisor supports only x86\_64 and requires Linux {{< required_linux >}}.
+> Note: gVisor supports only x86\_64 and requires Linux {{< required_linux >}}
+> ([older Linux][old-linux]).
 
 {{% readfile file="docs/includes/install_gvisor.md" markdown="true" %}}
 
@@ -47,3 +48,4 @@ sudo runsc run hello
 Next try [running gVisor using Docker](../docker/).
 
 [oci]: https://opencontainers.org/
+[old-linux]: /docs/user_guide/networking/#gso
-- 
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