net: increase optmem_max default value
For many years, /proc/sys/net/core/optmem_max default value
on a 64bit kernel has been 20 KB.
Regular usage of TCP tx zerocopy needs a bit more.
Google has used 128KB as the default value for 7 years without
any problem.
cos-patch: bug
Change-Id: I16786b4957fa98f1e9f6c1ece2d580d813dd201d
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 4944566706b27918ca15eda913889db296792415)
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/62582
Tested-by: Mina Almasry <almasrymina@google.com>
(cherry picked from commit 5dd3b994c20b595c241187bba6e3240eefe7f157)
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/62739
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Oleksandr Tymoshenko <ovt@google.com>
Main-Branch-Verified: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst
index 806ecd5..a454ef3 100644
--- a/Documentation/admin-guide/sysctl/net.rst
+++ b/Documentation/admin-guide/sysctl/net.rst
@@ -327,7 +327,10 @@
----------
Maximum ancillary buffer size allowed per socket. Ancillary data is a sequence
-of struct cmsghdr structures with appended data.
+of struct cmsghdr structures with appended data. TCP tx zerocopy also uses
+optmem_max as a limit for its internal structures.
+
+Default : 128 KB
fb_tunnels_only_for_init_net
----------------------------
diff --git a/net/core/sock.c b/net/core/sock.c
index fea3a16..03e0d7c 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -276,8 +276,10 @@ EXPORT_SYMBOL(sysctl_rmem_max);
__u32 sysctl_wmem_default __read_mostly = SK_WMEM_MAX;
__u32 sysctl_rmem_default __read_mostly = SK_RMEM_MAX;
-/* Maximal space eaten by iovec or ancillary data plus some space */
-int sysctl_optmem_max __read_mostly = sizeof(unsigned long)*(2*UIO_MAXIOV+512);
+/* Limits per socket sk_omem_alloc usage.
+ * TCP zerocopy regular usage needs 128 KB.
+ */
+int sysctl_optmem_max __read_mostly = 128 * 1024;
EXPORT_SYMBOL(sysctl_optmem_max);
int sysctl_tstamp_allow_data __read_mostly = 1;
