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From: David Woodhouse <dwmw2@infradead.org>
To: Artem Bityutskiy <dedekind@yandex.ru>
Cc: Chris Worley <worleys@gmail.com>, linux-fsdevel@vger.kernel.org
Subject: Re: What's the "prepare_discard_fn" supposed to do?
Date: Fri, 03 Oct 2008 07:53:46 +0100	[thread overview]
Message-ID: <1223016826.3328.11.camel@macbook.infradead.org> (raw)
In-Reply-To: <48E5C047.7020004@yandex.ru>

On Fri, 2008-10-03 at 09:48 +0300, Artem Bityutskiy wrote:
> Hi David,
> 
> David Woodhouse wrote:
> > It's intended to prepare the command which will be sent to the device,
> > much like the prepare_flush_fn does. See sd_prepare_flush() in
> > drivers/scsi/sd.c for an example (all the devices we've hooked up for
> > discard in Linux so far are virtual ones, so they don't make good
> > examples). I do have a real ATA drive with TRIM protocol support on its
> > way to me though, so I'll be looking at that some time soon.
> 
> Sorry for my ignorance, but why "discard" is used in hard drive? What
> may it improve? I've always been thinking it is only useful for SSD and
> other FTL-enabled beasts.

I said 'real ATA drive'. I didn't say it was magnetic.

-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse@intel.com                              Intel Corporation


  reply	other threads:[~2008-10-03  6:53 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-02 13:45 What's the "prepare_discard_fn" supposed to do? Chris Worley
2008-10-02 13:52 ` David Woodhouse
2008-10-03  6:48   ` Artem Bityutskiy
2008-10-03  6:53     ` David Woodhouse [this message]
2008-10-10 12:58     ` Matthew Wilcox

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