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net: increase optmem_max default value

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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.

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>
This commit is contained in:
Eric Dumazet 2023-12-14 10:48:59 +00:00 committed by David S. Miller
parent e16064c9af
commit 4944566706
2 changed files with 8 additions and 3 deletions
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5
Documentation/admin-guide/sysctl/net.rst
View File

@ -345,7 +345,10 @@ optmem_max
----------
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
----------------------------

6
net/core/sock.c
View File

@ -283,8 +283,10 @@ 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;