Re: XFS: Fine-tuning for checks before the function call "xfs_qm_dqrele"?

From	Dave Chinner <david@fromorbit.com>
Newsgroups	linux.kernel
Subject	Re: XFS: Fine-tuning for checks before the function call "xfs_qm_dqrele"?
Date	2015-07-02 02:30 +0200
Message-ID	<pHAy5-3RE-5@gated-at.bofh.it> (permalink)
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Organization	linux.* mail to news gateway

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On Wed, Jul 01, 2015 at 09:50:00AM +0200, SF Markus Elfring wrote:
> > xfs_dqrele_inode() gets called on every inode in the inode cache,
> > and this change results in a cacheline in every inode being dirtied
> > even if they don't have dquots attached. Given the inode cache can
> > hold tens to hundreds of millions of inodes on large machines, we
> > don't want to dirty any cachelines we don't need to while walking
> > the inode cache and releasing dquots...
> 
> Would it make sense to annotate checks before such function calls
> as "LIKELY"?

No - it will be random as to whether the inodes have dquots attached
or not and so a static hint is always going to be wrong for
someone....

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com
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Re: [PATCH] XFS: Delete unnecessary checks before the function call  "xfs_qm_dqrele" Dave Chinner <david@fromorbit.com> - 2015-06-29 23:50 +0200
  Re: XFS: Fine-tuning for checks before the function call "xfs_qm_dqrele"? SF Markus Elfring <elfring@users.sourceforge.net> - 2015-07-01 10:00 +0200
    Re: XFS: Fine-tuning for checks before the function call  "xfs_qm_dqrele"? Dave Chinner <david@fromorbit.com> - 2015-07-02 02:30 +0200

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