From: Ric Wheeler <ricwheeler@gmail.com>
To: Theodore Ts'o <tytso@mit.edu>
Cc: Eric Sandeen <sandeen@redhat.com>,
Julian Andres Klode <jak@jak-linux.org>,
Calvin Walton <calvin.walton@kepstin.ca>,
linux-ext4@vger.kernel.org
Subject: Re: Please help: Is ext4 counting trims as writes, or is something killing my SSD?
Date: Fri, 13 Sep 2013 09:41:22 -0400 [thread overview]
Message-ID: <52331602.4050404@gmail.com> (raw)
In-Reply-To: <20130912184732.GA28067@thunk.org>
On 09/12/2013 02:47 PM, Theodore Ts'o wrote:
> On Thu, Sep 12, 2013 at 10:52:38AM -0500, Eric Sandeen wrote:
>> However, it seems a little odd to me that ext4 feels it necessary to issue
>> discards on blocks which have been fallocated but not written to, I'll have
>> to think about that part (doesn't really matter for your case, it's just a
>> curiosity).
> For fstrim, we issue discards based on blocks which are not in use
> according to the block allocation bitmap.
>
> It shouldn't matter that we've issued discard on blocks which had been
> previously discarded, and in fact, it might help, since sometimes
> storage devices only traces block usage on large granularities ---
> that is, it might only releases blocks on a thin provisioned storage
> when a full megabyte worth of blocks are discarded.
>
> - Ted
>
It is the right thing to do to re-issue the trims I think for exactly that
reason. Devices are allowed by the spec to ignore requests that are not aligned
to their needs, so this lets us try to get back in sync.
ric
next prev parent reply other threads:[~2013-09-13 13:41 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-12 14:18 Please help: Is ext4 counting trims as writes, or is something killing my SSD? Julian Andres Klode
2013-09-12 14:26 ` Julian Andres Klode
2013-09-12 14:54 ` Calvin Walton
2013-09-12 15:03 ` Julian Andres Klode
2013-09-12 15:18 ` Eric Sandeen
2013-09-12 15:29 ` Calvin Walton
2013-09-12 15:33 ` Eric Sandeen
2013-09-12 15:32 ` Julian Andres Klode
2013-09-12 15:52 ` Eric Sandeen
2013-09-12 18:47 ` Theodore Ts'o
2013-09-13 13:41 ` Ric Wheeler [this message]
2013-09-13 13:38 ` Ric Wheeler
2013-09-12 15:19 ` Julian Andres Klode
2013-09-12 15:28 ` Theodore Ts'o
2013-09-12 15:29 ` Lukáš Czerner
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