netdev - Re: setsockopt()

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20080709184329.GC5383@2ka.mipt.ru>
Date:	Wed, 9 Jul 2008 22:43:30 +0400
From:	Evgeniy Polyakov <johnpol@....mipt.ru>
To:	"J. Bruce Fields" <bfields@...ldses.org>
Cc:	Bill Fink <billfink@...dspring.com>,
	Stephen Hemminger <stephen.hemminger@...tta.com>,
	Roland Dreier <rdreier@...co.com>,
	David Miller <davem@...emloft.net>, aglo@...i.umich.edu,
	shemminger@...tta.com, netdev@...r.kernel.org, rees@...ch.edu
Subject: Re: setsockopt()

On Wed, Jul 09, 2008 at 02:11:22PM -0400, J. Bruce Fields (bfields@...ldses.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
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html