Re: [PATCH 0/4] dcache: make Oracle more scalable on large systems

From: Andi Kleen
Date: Thu Feb 21 2013 - 19:13:53 EST


Dave Chinner <david@xxxxxxxxxxxxx> writes:

> On Tue, Feb 19, 2013 at 01:50:55PM -0500, Waiman Long wrote:
>> It was found that the Oracle database software issues a lot of call
>> to the seq_path() kernel function which translates a (dentry, mnt)
>> pair to an absolute path. The seq_path() function will eventually
>> take the following two locks:
>
> Nobody should be doing reverse dentry-to-name lookups in a quantity
> sufficient for it to become a performance limiting factor. What is
> the Oracle DB actually using this path for?

Yes calling d_path frequently is usually a bug elsewhere.
Is that through /proc ?

-Andi


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