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From: Christoph Hellwig <hch@infradead.org>
To: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>, linux-fsdevel@vger.kernel.org
Subject: Re: quota tests
Date: Tue, 6 Sep 2011 11:15:05 -0400	[thread overview]
Message-ID: <20110906151505.GA7213@infradead.org> (raw)
In-Reply-To: <20110906151236.GG23747@quack.suse.cz>

On Tue, Sep 06, 2011 at 05:12:36PM +0200, Jan Kara wrote:
>   To verify reclaim behavior for VFS quotas, we could pull quota structures
> in memory using GETQUOTA and then apply memory pressure to have them
> reclaimed. If we also want to combine this with updates to those structures
> because of allocations it gets more complicated. We'd have to do IO for
> several different users in sequence under memory pressure so that all
> inodes of one user get pushed out of memory and quota structure is thus
> freed for reclaim as well.
> 
>   As for racing lookups / other quota operations - these are not that
> much interesting for VFS quotas because
>   a) once quota structure is created, it's position on disk is fixed
>   b) any operation on quota file that does more than update accounting
> information in a structure is protected by per quota-file mutex.
>   c) in memory operations with quota structures are protected by one global
> spinlock

It's fairly similar for XFS - but we still have code to e.g. retry the
lookup after we did a memory allocation in both quota implementation.

I just change the way the one in XFS worked, so I'm looking for a way
to actually test that path.  


  reply	other threads:[~2011-09-06 15:15 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-06 12:21 quota tests Christoph Hellwig
2011-09-06 14:43 ` Jan Kara
2011-09-06 14:50   ` Christoph Hellwig
2011-09-06 15:12     ` Jan Kara
2011-09-06 15:15       ` Christoph Hellwig [this message]
2011-09-06 14:50   ` Jan Kara

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