From: Keith Busch <keith.busch@intel.com>
To: Ric Wheeler <ricwheeler@gmail.com>
Cc: Dave Chinner <david@fromorbit.com>,
lsf-pc@lists.linux-foundation.org,
linux-xfs <linux-xfs@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-ext4 <linux-ext4@vger.kernel.org>,
linux-btrfs <linux-btrfs@vger.kernel.org>,
linux-block@vger.kernel.org
Subject: Re: [LSF/MM TOPIC] More async operations for file systems - async discard?
Date: Wed, 20 Feb 2019 16:47:24 -0700 [thread overview]
Message-ID: <20190220234723.GA5999@localhost.localdomain> (raw)
In-Reply-To: <46540876-c222-0889-ddce-44815dcaad04@gmail.com>
On Sun, Feb 17, 2019 at 06:42:59PM -0500, Ric Wheeler wrote:
> I think the variability makes life really miserable for layers above it.
>
> Might be worth constructing some tooling that we can use to validate or
> shame vendors over - testing things like a full device discard, discard of
> fs block size and big chunks, discard against already discarded, etc.
With respect to fs block sizes, one thing making discards suck is that
many high capacity SSDs' physical page sizes are larger than the fs block
size, and a sub-page discard is worse than doing nothing.
We've discussed previously about supporting block size larger than
the system's page size, but it doesn't look like that's gone anywhere.
Maybe it's worth revisiting since it's really inefficient if you write
or discard at the smaller granularity.
next prev parent reply other threads:[~2019-02-20 23:47 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-17 20:36 [LSF/MM TOPIC] More async operations for file systems - async discard? Ric Wheeler
2019-02-17 21:09 ` Dave Chinner
2019-02-17 23:42 ` Ric Wheeler
2019-02-18 2:22 ` Dave Chinner
2019-02-18 22:30 ` Ric Wheeler
2019-02-20 23:47 ` Keith Busch [this message]
2019-02-21 20:08 ` Dave Chinner
2019-02-21 23:55 ` Jeff Mahoney
2019-02-22 3:01 ` Martin K. Petersen
2019-02-22 6:15 ` Roman Mamedov
2019-02-22 14:12 ` Martin K. Petersen
2019-02-22 2:51 ` Martin K. Petersen
2019-02-22 16:45 ` Keith Busch
2019-02-27 11:40 ` Ric Wheeler
2019-02-27 13:24 ` Matthew Wilcox
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