Re: setsockopt()

[Evgeniy Polyakov <johnpol@2ka.mipt.ru>]

On Wed, Jul 09, 2008 at 02:11:22PM -0400, J. Bruce Fields (bfields@fieldses.org) wrote:
> > Yeah, its a bit confusing. It probably was copypasted, there is no
> > default, but minimum possible value.
> 
> I don't understand; what do you mean by "there is no default"?  (And if
> not, what does tcp_wmem[1] mean?)

I meant there is no default value for tcp_w/rmem[2], which is calculated
based on tcp_mem, which in turn is calculated based on amount RAM of in
the system. tcp_wmem[2] will be at least 64k, but its higher limit
(calculated by system, which of course can be overwritten) is RAM/256 on
x86 (iirc only low mem is counted, although that was different in
various kernel versions), but not more than 4Mb.

tcp_wmem[1] means initial send buffer size, it can grow up to tcp_wmem[2].
There is a default for this parameter. Actually all this numbers are a
bit fluffy, so they are kind of soft rules for socket memory accounting
mechanics.

-- 
	Evgeniy Polyakov