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Date: Fri, 8 Feb 2002 11:11:50 -0800 (PST)
From: Linus Torvalds <torvalds@transmeta.com>
To: Andrew Morton <akpm@zip.com.au>
cc: Martin Wirth <Martin.Wirth@dlr.de>, Robert Love <rml@tech9.net>,
        <linux-kernel@vger.kernel.org>, <mingo@elte.hu>, <haveblue@us.ibm.com>
Subject: Re: [RFC] New locking primitive for 2.5
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On Fri, 8 Feb 2002, Andrew Morton wrote:
>
> Yesterday, Ingo said:
>
> > i think one example *could* be to turn inode->i_sem into a combi-lock. Eg.
> > generic_file_llseek() could use the spin variant.
> >
> > this is a real performance problem, i've seen scheduling storms in
> > dbench-type runs due to llseek taking the inode semaphore.

... so just make it a spinlock instead.

The semaphore is overkill, as the only thing we're really protecting is
one 64-bit access against other updates.

		Linus

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