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From: Andrew Morton <akpm@osdl.org>
To: Hannes Reinecke <hare@suse.de>
Cc: linux-hotplug-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Limit number of concurrent hotplug processes
Date: Mon, 26 Jul 2004 01:20:06 +0000	[thread overview]
Message-ID: <20040725182006.6c6a36df.akpm@osdl.org> (raw)
In-Reply-To: <40FD23A8.6090409@suse.de>

Hannes Reinecke <hare@suse.de> wrote:
>
> the attached patch limits the number of concurrent hotplug processes.
>  Main idea behind it is that currently each call to call_usermodehelper 
>  will result in an execve() of "/sbin/hotplug", without any check whether 
>  enough resources are available for successful execution. This leads to 
>  hotplug being stuck and in worst cases to machines being unable to boot.
> 
>  This check cannot be implemented in userspace as the resources are 
>  already taken by the time any resource check can be done; for the same 
>  reason any 'slim' programs as /sbin/hotplug will only delay the problem.

hm, it's a bit sad that this happens.  Are you able to tell us more about
what is causing such an explosion of module probes?

>  Any comments/suggestions welcome; otherwise please apply.

I suggest you just use a semaphore, initialised to a suitable value:


static struct semaphore foo = __SEMAPHORE_INITIALIZER(foo, 50);


{
	...
	down(&foo);
	...
	up(&foo);
	...
}



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  reply	other threads:[~2004-07-26  1:20 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-07-20 13:52 [PATCH] Limit number of concurrent hotplug processes Hannes Reinecke
2004-07-26  1:20 ` Andrew Morton [this message]
2004-07-26  6:19   ` Christian Borntraeger
2004-07-26 10:59   ` Hannes Reinecke
2004-07-26 20:18     ` Andrew Morton
2004-07-27  7:04       ` Hannes Reinecke
2004-07-27  7:24         ` Andrew Morton
2004-07-27  7:59           ` Hannes Reinecke
2004-07-27  8:34             ` Andrew Morton
2004-07-27  9:05               ` Hannes Reinecke
2004-07-27  9:28                 ` Andrew Morton
2004-07-27 12:22                   ` Hannes Reinecke
2004-07-28  7:12                   ` Paul Jackson

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