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Re: [PATCH 9/9] xfs: factor buffer reading from xfs_dir2_leaf_getdents

To: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Subject: Re: [PATCH 9/9] xfs: factor buffer reading from xfs_dir2_leaf_getdents
From: Dave Chinner <david@xxxxxxxxxxxxx>
Date: Wed, 20 Jun 2012 17:41:17 +1000
Cc: xfs@xxxxxxxxxxx
In-reply-to: <20120620072709.GA27358@xxxxxxxxxxxxx>
References: <1339133914-11148-1-git-send-email-david@xxxxxxxxxxxxx> <1339133914-11148-10-git-send-email-david@xxxxxxxxxxxxx> <20120620072709.GA27358@xxxxxxxxxxxxx>
User-agent: Mutt/1.5.21 (2010-09-15)
On Wed, Jun 20, 2012 at 03:27:10AM -0400, Christoph Hellwig wrote:
> > +struct _map_info {
> > +   xfs_bmbt_irec_t *map;           /* map vector for blocks */
> > +   xfs_extlen_t    map_blocks;     /* number of fsbs in map */
> > +   xfs_dablk_t     map_off;        /* last mapped file offset */
> > +   int             map_size;       /* total entries in *map */
> > +   int             map_valid;      /* valid entries in *map */
> > +   int             nmap;           /* mappings to ask xfs_bmapi */
> > +   xfs_dir2_db_t   curdb;          /* db for current block */
> > +};
> > +
> > +struct _ra_info {
> 
> Can you give these structure names xfs_dir2_leaf prefixes, please?

Sure.

> Also any reason the ra_info structure is kept entirely separate?

Logical grouping, easy to validate.

> While
> I see a bit of a point to have a logical grouping, it still semes more
> useful to just embedd it into the map_info.

Ok, I can do that.

> > +   map_info.map_size = howmany(bufsize + mp->m_dirblksize,
> > +                                mp->m_sb.sb_blocksize);
> > +   map_info.map = kmem_zalloc(map_info.map_size *
> > +                                   sizeof(struct xfs_bmbt_irec), KM_SLEEP);
> 
> I'd be tempted to say that the map field in the map_info should be a
> variable sized array the end, and the whole structure should be
> dynamically allocated to get a couple more variables off the stack.

Makes sense, even though we aren't usually under stack pressure
here.

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx

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