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Date: Mon, 21 Apr 2003 11:28:58 -0700
From: Andrew Morton <akpm@digeo.com>
To: Manfred Spraul <manfred@colorfullife.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Q: nr_threads locking
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Manfred Spraul <manfred@colorfullife.com> wrote:
>
> Hi Andrew,
> 
> According to the comments, nr_threads is protected by lock_kernel, but 
> do_fork() runs without the bkl for ages.
> Would it be possible to use your percpu_counters for nr_threads? It 
> seems to be used only to guard against fork bombs and for i_nlink of /proc.
> 

It would be possible, yes.

But thread creation is a "rare" event compared to pagefaults and syscalls. 
An atomic_t will be OK there.