From owner-freebsd-arch@FreeBSD.ORG  Mon Apr 13 08:52:35 2015
Return-Path: <owner-freebsd-arch@FreeBSD.ORG>
Delivered-To: arch@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 3EA44CC3
 for <arch@freebsd.org>; Mon, 13 Apr 2015 08:52:35 +0000 (UTC)
Received: from zxy.spb.ru (zxy.spb.ru [195.70.199.98])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id E8AAE839
 for <arch@freebsd.org>; Mon, 13 Apr 2015 08:52:34 +0000 (UTC)
Received: from slw by zxy.spb.ru with local (Exim 4.84 (FreeBSD))
 (envelope-from <slw@zxy.spb.ru>)
 id 1Yha6V-000JPA-CE; Mon, 13 Apr 2015 11:52:27 +0300
Date: Mon, 13 Apr 2015 11:52:27 +0300
From: Slawa Olhovchenkov <slw@zxy.spb.ru>
To: Poul-Henning Kamp <phk@phk.freebsd.dk>
Subject: Re: default file descriptor limit ?
Message-ID: <20150413085227.GO1394@zxy.spb.ru>
References: <78759.1428912996@critter.freebsd.dk>
 <79209.1428913320@critter.freebsd.dk>
 <20150413083159.GN1394@zxy.spb.ru>
 <97929.1428914379@critter.freebsd.dk>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <97929.1428914379@critter.freebsd.dk>
User-Agent: Mutt/1.5.23 (2014-03-12)
X-SA-Exim-Connect-IP: <locally generated>
X-SA-Exim-Mail-From: slw@zxy.spb.ru
X-SA-Exim-Scanned: No (on zxy.spb.ru); SAEximRunCond expanded to false
Cc: arch@freebsd.org
X-BeenThere: freebsd-arch@freebsd.org
X-Mailman-Version: 2.1.18-1
Precedence: list
List-Id: Discussion related to FreeBSD architecture <freebsd-arch.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-arch>,
 <mailto:freebsd-arch-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-arch/>
List-Post: <mailto:freebsd-arch@freebsd.org>
List-Help: <mailto:freebsd-arch-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
 <mailto:freebsd-arch-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 13 Apr 2015 08:52:35 -0000

On Mon, Apr 13, 2015 at 08:39:39AM +0000, Poul-Henning Kamp wrote:

> --------
> In message <20150413083159.GN1394@zxy.spb.ru>, Slawa Olhovchenkov writes:
> 
> >> >This wastes tons of pointless close system calls in programs which
> >> >use the suboptimal but best practice:
> >> >
> >> >	for (i = 3; i < sysconf(_SC_OPEN_MAX); i++)
> >> >		close(i);
> >> >
> >> >For reference Linux seems to default to 1024, leaving it up to
> >> >massive server processes to increase the limit for themselves.
> >
> >This is typical only on startup, I think?
> 
> No.  This is mandatory whenever you spawn an sub process with less privilege.

Hmm.
1. Whats [linux] application do this?
2. For case of reduce this limit -- how spawned application can
increase this limit, if need? I am not sure, this is posible?

> >May be now time to introduce new login class, for desktop users, [...]
> 
> How about "now is the time to realize that very few processes need more
> than a few tens of filedescriptors" ?
> 
> If Linux can manage with a hardcoded default of 1024, so can we...

And have many FAQs "how to overcome this restriction". Including "libc
recompile"