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Date: Mon, 23 Mar 2015 15:28:47 +1100
From: Dave Chinner <david@fromorbit.com>
Subject: Re: Question about GFP_KERNEL argument in radix_tree_preload
Message-ID: <20150323042847.GN28621@dastard>
References: <CADa969g-jGyYc1ts+JamuD0Ze-Mcp+X8am7rAfDeY0wXC4A6gg@mail.gmail.com>
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To: Sanidhya Kashyap <sanidhya.gatech@gmail.com>
Cc: taesoo@gatech.edu, "Kashyap, Sanidhya" <sanidhya@gatech.edu>, xfs@oss.sgi.com, csong@gatech.edu, blee@gatech.edu, changwoo@gatech.edu

On Sun, Mar 22, 2015 at 11:49:34PM -0400, Sanidhya Kashyap wrote:
> Hello David,
> 
> We have been doing some analysis on file systems and have a question
> regarding the GFP_KERNEL flag used in radix_tree_preload in
> xfs_mru_cache_insert.
> 
> We think that this should be GFP_NOFS as it is related to the block
> allocation and other file systems(eg btrfs,ext2) are also using
> GFP_NOFS for the same.
>
> It would be great if you can let us know your reason for using that
> flag and which one is the correct option?

<shrug>

That code was written by someone else and it was 7-8 years ago I
cleaned it up for Linux. Whatever reason there was is long since
lost.

If it's wrong (e.g. can be called inside a transaction), send a
patch to fix it.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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