From: Greg KH <gregkh@suse.de>
To: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] tty: rework pty count limiting
Date: Mon, 2 Jan 2012 09:29:03 -0800 [thread overview]
Message-ID: <20120102172903.GB19782@suse.de> (raw)
In-Reply-To: <20120102172301.11535.10338.stgit@zurg>
On Mon, Jan 02, 2012 at 09:23:01PM +0400, Konstantin Khlebnikov wrote:
> After adding devpts multiple-insrances sysctl kernel.pty.max limit pty count for
> each devpts instance independently, while kernel.pty.nr shows total pty count.
>
> This patch restores sysctl kernel.pty.max as global limit (4096 by default),
> adds pty reseve for main devpts (mounted without "newinstance" argument),
> and new sysctl to tune it: kernel.pty.reserve (1024 by default)
>
> Also it adds devpts mount option "max=%d" to limit pty count for each devpts
> instance independently. (by default NR_UNIX98_PTY_MAX == 2^20)
>
> Thus devpts instances in containers cannot eat up all available pty even if we didn't
> set any limits, while with "max" argument we can adjust limits more precisely.
>
> Plus, now open("/dev/ptmx") return -ENOSPC in case lack of pty indexes,
> this is more informative than -EIO.
That's a userspace api change, why is this going to be allowed?
greg k-h
next prev parent reply other threads:[~2012-01-02 17:29 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-02 17:22 [PATCH 1/2] tty: move pty count limiting into devpts Konstantin Khlebnikov
2012-01-02 17:23 ` [PATCH 2/2] tty: rework pty count limiting Konstantin Khlebnikov
2012-01-02 17:29 ` Greg KH [this message]
2012-01-02 22:21 ` Konstantin Khlebnikov
2012-01-03 0:43 ` Alan Cox
2012-01-05 0:24 ` [PATCH 1/2] tty: move pty count limiting into devpts Greg KH
2012-01-05 9:06 ` [PATCH for tty-next " Konstantin Khlebnikov
2012-01-05 9:06 ` [PATCH for tty-next 2/2] tty: rework pty count limiting Konstantin Khlebnikov
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