From: Theodore Ts'o <tytso@mit.edu>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>, Jens Axboe <axboe@kernel.dk>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
linux-fsdevel@vger.kernel.org,
linux-ext4 <linux-ext4@vger.kernel.org>
Subject: Re: BLKZEROOUT + pread should return zeroes, right?
Date: Tue, 14 Oct 2014 02:32:10 -0400 [thread overview]
Message-ID: <20141014063210.GK9738@thunk.org> (raw)
In-Reply-To: <20141014060242.GA22878@birch.djwong.org>
The bottom line is for most of the use cases we are talking about,
we're only zero'ing one or two 4k blocks at a time, so I've never been
convinced that it's worth it to use BLKZEROOUT.
We could add page cache coherency features to BLKZEROOUT, but I'm not
entirely sure it's worth the effort. No user space program would be
able to take advantage of adding coherency for several years, or
adding feature tests, etc., and is it worth the upside of being able
to use WRITE SAME for a few 4k or 8k writes? (Which the vast majority
of storage devices don't support anyway....)
Cheers,
- Ted
next prev parent reply other threads:[~2014-10-14 6:32 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-14 3:01 BLKZEROOUT + pread should return zeroes, right? Darrick J. Wong
2014-10-14 4:27 ` Dave Chinner
2014-10-14 6:02 ` Darrick J. Wong
2014-10-14 6:32 ` Theodore Ts'o [this message]
2014-10-15 1:25 ` Darrick J. Wong
2014-10-15 1:32 ` Martin K. Petersen
2014-10-16 20:04 ` Darrick J. Wong
2014-10-15 10:02 ` Theodore Ts'o
2014-10-15 12:09 ` Martin K. Petersen
2014-10-18 0:03 ` [RFC PATCH] block: make BLKZEROOUT invalidate page cache contents Darrick J. Wong
2014-10-14 9:21 ` BLKZEROOUT + pread should return zeroes, right? Christoph Hellwig
2014-10-14 13:44 ` Martin K. Petersen
2014-10-14 18:57 ` Zach Brown
2014-10-14 20:21 ` Dave Chinner
2014-10-15 1:02 ` Martin K. Petersen
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