[PATCH v1][libnl3] lib/nl: Increase default receive socket buffer size to 128k

[Thomas Haller]

On Wed, 2015-12-09 at 22:22 -0500, Leno Hou wrote:
> From: Leno Hou <houqy at linux.vnet.ibm.com>
> 
> This patch set default receive socket buffer size to 128K to solve
> nl_recv returned with error: No buffer space available
> 1. When switching CPUs to offline/online in a system more than 128
> cpus
> 2. When using virsh to destroy domain in a system with more
> interfaces
> 3. When NetworkMananger monitoring some uevents,e.g. netlink is
> changed.

Hi,


Changing the default affects every user. It's not clear to me, that
128k is a better default for everybody.

The user already can change this (either via
nl_socket_set_buffer_size() or directly via ioctl on the file
descriptor).


I tried to figure out why NetworkManager sets the buffer size.
Currently I wasn't able to reproduce a failure related to a smaller
SO_RCVBUF. I'm almost inclined to remove the set_buffer_size() call
from NetworkManager, at least it's not at all clear that this patch is
right.


Can you justify the change better?
Your examples are:
  1.) affects systems with >128 CPU? Unusual case, I cannot
      reproduce :)
  2.) virsh. OK.
  3.) maybe, but I wonder if NM actually needs this.


Thomas
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