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Subject: Re: [patch 03/33] fs: scale files_lock
From: Peter Zijlstra <peterz@infradead.org>
To: npiggin@suse.de
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
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Date: Mon, 28 Sep 2009 15:22:19 +0200
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On Fri, 2009-09-04 at 16:51 +1000, npiggin@suse.de wrote:
> +static void file_list_lock_all(void)
> +{
> +       int i;
> +       int nr = 0;
> +
> +       for_each_possible_cpu(i) {
> +               spinlock_t *lock;
> +
> +               lock = &per_cpu(files_cpulock, i);
> +               spin_lock_nested(lock, nr);
> +               nr++;
> +       }
> +}

Same here, this'll make lockdep explode on >8-way. And create large spin
times on large smp boxen.