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From: Andrew Morton <akpm@linux-foundation.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: linux-kernel@vger.kernel.org, eric.dumazet@gmail.com,
	Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH 2/4] posix-timers: limit the number of posix timers per process
Date: Tue, 30 Aug 2011 14:44:07 -0700	[thread overview]
Message-ID: <20110830144407.acdae071.akpm@linux-foundation.org> (raw)
In-Reply-To: <1314661157-22173-2-git-send-email-andi@firstfloor.org>

On Mon, 29 Aug 2011 16:39:15 -0700
Andi Kleen <andi@firstfloor.org> wrote:

> Now this is the main reason I wrote the whole patchkit: previously
> there was no limit on the maximum number of POSIX timers a process
> could allocate.  This limits the amount of unswappable kernel memory
> a process can pin down this way.
> 
> With the POSIX timer ids being per process we can do this limit
> per process now without allowing one process DoSing another.
> 
> I implemented it as a sysctl, not a rlimit for now, because
> there was no clear use case for rlimit.
> 
> The 1024 default is completely arbitrary, but seems reasonable
> for now.

Sorry, it should be an rlimit from day one, IMO.

Partly because rlimits are a better implementation.

Partly because if we later do it via rlimit, we're stuck having to
maintain the /proc knob for ever.

Partly because once rlimits are added, the /proc knob no longer has any
sane behaviour.  Does it only modify /sbin/init?  Does it do a global
process walk, modifying all threads?

  reply	other threads:[~2011-08-30 21:44 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-29 23:39 [PATCH 1/4] posix-timers: move global timer id management to signal_struct v2 Andi Kleen
2011-08-29 23:39 ` [PATCH 2/4] posix-timers: limit the number of posix timers per process Andi Kleen
2011-08-30 21:44   ` Andrew Morton [this message]
2011-08-30 22:06     ` Andi Kleen
2011-08-30 22:22       ` Andrew Morton
2011-08-30 22:47         ` Andi Kleen
2011-08-30 23:02           ` Andrew Morton
2011-08-31  6:45             ` Jiri Slaby
2011-09-02  9:30   ` Thomas Gleixner
2011-08-29 23:39 ` [PATCH 3/4] posix-timers: Don't disable interrupts in idr_lock Andi Kleen
2011-08-29 23:39 ` [PATCH 4/4] posix-timers: turn it_signal into it_valid flag Andi Kleen
2011-09-02 10:06   ` Thomas Gleixner
2011-09-02 11:49     ` Eric Dumazet
2011-09-02 14:19       ` Thomas Gleixner
2011-09-04 16:56     ` Oleg Nesterov
2011-09-04 19:07       ` Andi Kleen
2011-09-04 20:29       ` Oleg Nesterov
2011-09-06  3:14         ` Andi Kleen
2011-09-06 14:51           ` Oleg Nesterov
2011-09-06 15:39             ` Eric Dumazet
2011-09-06 16:27               ` Oleg Nesterov
2011-09-06 18:47               ` Thomas Gleixner
2011-09-06 18:49                 ` Oleg Nesterov
2011-09-06 19:16                   ` Thomas Gleixner
2011-09-06 19:26                     ` Oleg Nesterov
2011-09-06 19:45                       ` Thomas Gleixner
2011-09-06 22:08                         ` Oleg Nesterov
2011-09-06 22:34                           ` Thomas Gleixner
2011-09-21 16:46                           ` Thomas Gleixner
2011-09-21 17:56                             ` Thomas Gleixner
2011-09-22 11:19                               ` Thomas Gleixner
2011-09-06 19:30                     ` Eric Dumazet
2011-09-06 20:10                       ` Thomas Gleixner
2011-09-06 20:27                         ` Eric Dumazet
2011-09-06 19:04                 ` Eric Dumazet
2011-08-31  8:53 ` [PATCH 1/4] posix-timers: move global timer id management to signal_struct v2 Eric Dumazet
2011-08-31 16:57   ` Andi Kleen
2011-09-02  9:19 ` Thomas Gleixner
2011-09-02 10:05   ` Eric Dumazet
2011-09-19 21:46   ` Andi Kleen

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