From: Sami Liedes <sami.liedes@iki.fi>
To: Ted Ts'o <tytso@mit.edu>
Cc: Andreas Dilger <adilger@dilger.ca>, linux-ext4@vger.kernel.org
Subject: Re: [PATCH 4/5] libext2fs: Implement ext2fs_find_first_zero_generic_bmap().
Date: Mon, 26 Mar 2012 16:53:56 +0300 [thread overview]
Message-ID: <20120326135355.GB2180@cc.hut.fi> (raw)
In-Reply-To: <20120323223331.GA8554@thunk.org>
On Fri, Mar 23, 2012 at 06:33:31PM -0400, Ted Ts'o wrote:
> It would then be very easy to build iterators on *top* of
> find_first_zero() and find_first_set(), and in fact this could be used
> to replace some of the places where we are using a sorted list (i.e.,
> the badblocks list). So that sounds like a good idea, and I can
> definitely think of some places where we could use that code today.
>
> So I plan to pull in your patch series and then we can further enhance
> this with iterator support afterwards. Sami, if you'd be interested
> in implementing iterators, that would be great!
Just to be on the same page, what is the motivation for iterators? Is
it performance, making the code cleaner or facilitating further
functionality?
If it's driven by performance concerns, it would be good to first have
a case where they cause performance problems. Otherwise it would be
good to first figure out a program in the e2fsprogs suite that
exercises (or could exercise) the code in question, just for testing.
My work on inode allocation was actually entirely driven by a friend's
observation that resize2fs took 16 CPU hours to shrink a filesystem.
Profile-guided optimization is something I generally do a lot, but I'm
not averse to doing other kinds of useful coding tasks for useful open
source projects.
Sami
next prev parent reply other threads:[~2012-03-26 13:53 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-10 21:33 [PATCH 0/5] Make filesystem shrinking faster and less CPU-intensive Sami Liedes
2012-03-10 21:34 ` [PATCH 1/5] libext2fs: Move a modulo operation out of a hot loop Sami Liedes
2012-03-11 9:50 ` Andreas Dilger
2012-03-10 21:35 ` [PATCH 2/5] resize2fs: Use EXT2_FLAG_64BITS Sami Liedes
2012-03-10 21:36 ` [PATCH 3/5] libext2fs: Document EXT2_FLAG_64BITS in ext2fs_open2() Sami Liedes
2012-03-10 21:37 ` [PATCH 4/5] libext2fs: Implement ext2fs_find_first_zero_generic_bmap() Sami Liedes
2012-03-11 9:51 ` Andreas Dilger
2012-03-12 19:15 ` Sami Liedes
2012-03-12 23:09 ` Andreas Dilger
2012-03-23 22:33 ` Ted Ts'o
2012-03-26 13:53 ` Sami Liedes [this message]
2012-03-26 15:34 ` Ted Ts'o
2012-03-26 2:39 ` Ted Ts'o
2012-03-10 21:38 ` [PATCH 5/5] libext2fs: Implement fast find_first_zero() for bitarray bitmaps Sami Liedes
2012-03-26 2:34 ` Ted Ts'o
2012-03-26 13:22 ` Sami Liedes
2012-03-26 15:26 ` Ted Ts'o
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