From: Joel Becker <Joel.Becker@oracle.com>
To: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Jeff Garzik <jeff@garzik.org>, "Theodore Ts'o" <tytso@mit.edu>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: Proposal and plan for ext2/3 future development work
Date: Fri, 30 Jun 2006 11:24:57 -0700 [thread overview]
Message-ID: <20060630182457.GH11640@ca-server1.us.oracle.com> (raw)
In-Reply-To: <1151687586.339.5.camel@dyn9047017100.beaverton.ibm.com>
On Fri, Jun 30, 2006 at 10:13:06AM -0700, Badari Pulavarty wrote:
> I tried adding "delayed allocation" for ext3 earlier. Yes. VFS level
> infrastructure would be nice. But, I haven't found much that we can
> do at VFS - which is common across all the filesystems (except
> mpage_writepage(s) handling). Most of the stuff is specific to
> filesystem implementation (even though it could be common) - coming
> out with VFS level interfaces to suite all the different filesystem
> delalloc would be *interesting* exercise.
Well, to be fair, I'm just going by what little I know about
XFS. They maintain a cache of all pages waiting on delayed allocation
for writepack. Why have this entire cache (hash, list, whatever) when
we could create some state on in the pagecache? We save a large chunk
of memory and some complex writeback code. I suspect you were thinking
of this when you said "mpage_writepage(s) handling". But this is a
large complexity win if we can do it.
The same with metadata/data ordering issues. ie, data=ordered
or even plain "creat(2); write(2)". I don't know how generic the
ordering is for each filesystem, but there is always room for play.
On-disk, of course each filesystem is going to be different.
I'm not sure we could fit a fully-generic aops->reserve_space() &
aops->commit_space() API. But I don't think we need to.
Joel
--
"Well-timed silence hath more eloquence than speech."
- Martin Fraquhar Tupper
Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker@oracle.com
Phone: (650) 506-8127
next prev parent reply other threads:[~2006-06-30 18:28 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-28 23:55 Proposal and plan for ext2/3 future development work Theodore Ts'o
2006-06-30 1:14 ` Jeff Garzik
2006-06-30 1:59 ` Joel Becker
2006-06-30 17:13 ` Badari Pulavarty
2006-06-30 18:24 ` Joel Becker [this message]
2006-06-30 19:17 ` Steve Lord
2006-06-30 19:29 ` Badari Pulavarty
2006-06-30 10:39 ` Andi Kleen
2006-06-30 15:14 ` Theodore Tso
2006-07-01 9:42 ` Adrian Bunk
2006-07-01 10:29 ` Theodore Tso
2006-06-30 11:09 ` Patrick McFarland
2006-06-30 23:44 ` Mingming Cao
2006-07-24 13:04 ` Guillaume Chazarain
2006-07-24 18:11 ` Jeff Garzik
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20060630182457.GH11640@ca-server1.us.oracle.com \
--to=joel.becker@oracle.com \
--cc=jeff@garzik.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbadari@us.ibm.com \
--cc=tytso@mit.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).