From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Chris Mason <chris.mason@oracle.com>
Cc: Nick Piggin <npiggin@suse.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
linux-fsdevel@vger.kernel.org
Subject: Re: [patch 1/3] add the fsblock layer
Date: Tue, 26 Jun 2007 12:42:27 +1000 [thread overview]
Message-ID: <46807D13.4070703@yahoo.com.au> (raw)
In-Reply-To: <20070625131917.GD12852@think.oraclecorp.com>
Chris Mason wrote:
> On Sun, Jun 24, 2007 at 03:46:13AM +0200, Nick Piggin wrote:
>
>>Rewrite the buffer layer.
>
>
> Overall, I like the basic concepts, but it is hard to track the locking
> rules. Could you please write them up?
Yeah I will do that.
Thanks for taking a look. One thing I am thinking about is to get
rid of the unmap_underlying_metadata calls from the generic code.
I found they were required for minix to prevent corruption, however
I don't know exactly what metadata is interfering here (maybe it
is indirect blocks or something?). Anyway, I think I will make it
a requirement that the filesystem has to already handle this before
returning a newly allocated block -- they can probably do it more
efficiently and we avoid the extra work on every block allocation.
> I like the way you split out the assoc_buffers from the main fsblock
> code, but the list setup is still something of a wart. It also provides
> poor ordering of blocks for writeback.
Yeah, I didn't know how much effort to put in here because I don't
know whether modern filesystems are going to need to implement their
own management of this stuff or not.
I haven't actually instrumented this in something like ext2 to see
how much IO comes from the assoc buffers...
> I think it makes sense to replace the assoc_buffers list head with a
> radix tree sorted by block number. mark_buffer_dirty_inode would up the
> reference count and put it into the radix, the various flushing routines
> would walk the radix etc.
>
> If you wanted to be able to drop the reference count once the block was
> written you could have a back pointer to the appropriate inode.
I was actually thinking about a radix-tree :) One annoyance is that
unsigned long != sector_t :P rbtree would probably be OK.
--
SUSE Labs, Novell Inc.
next prev parent reply other threads:[~2007-06-26 2:42 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-24 1:45 [RFC] fsblock Nick Piggin
2007-06-24 1:46 ` [patch 1/3] add the fsblock layer Nick Piggin
2007-06-24 15:28 ` Andi Kleen
2007-06-24 20:18 ` Arjan van de Ven
2007-06-25 8:58 ` Andi Kleen
2007-06-25 7:19 ` Nick Piggin
2007-06-24 23:01 ` Neil Brown
2007-06-25 7:41 ` Nick Piggin
2007-06-25 12:29 ` Chris Mason
2007-06-26 2:34 ` Nick Piggin
2007-06-26 2:48 ` Neil Brown
2007-06-26 3:07 ` Nick Piggin
2007-06-26 12:26 ` Chris Mason
2007-06-30 10:40 ` Christoph Hellwig
2007-06-30 10:40 ` Christoph Hellwig
2007-06-25 13:19 ` Chris Mason
2007-06-26 2:42 ` Nick Piggin [this message]
2007-06-24 1:46 ` [patch 2/3] block_dev: convert to fsblock Nick Piggin
2007-06-24 1:47 ` [patch 3/3] minix: " Nick Piggin
2007-06-24 1:53 ` [RFC] fsblock Nick Piggin
2007-06-24 3:07 ` Jeff Garzik
2007-06-24 3:47 ` Nick Piggin
2007-06-24 13:51 ` Chris Mason
2007-06-25 6:58 ` Nick Piggin
2007-06-25 12:25 ` Chris Mason
2007-06-30 10:44 ` Christoph Hellwig
2007-06-30 10:42 ` Christoph Hellwig
2007-06-30 11:10 ` Jeff Garzik
2007-06-30 11:13 ` Christoph Hellwig
2007-06-24 4:19 ` William Lee Irwin III
2007-06-24 14:16 ` Andi Kleen
2007-06-25 7:16 ` Nick Piggin
2007-06-26 3:06 ` David Chinner
2007-06-26 3:55 ` Nick Piggin
2007-06-26 9:23 ` David Chinner
2007-06-26 11:14 ` Nick Piggin
2007-06-27 12:39 ` Kyle Moffett
2007-06-26 12:34 ` Chris Mason
2007-06-27 5:32 ` Nick Piggin
2007-06-27 6:05 ` David Chinner
2007-06-27 11:50 ` Chris Mason
2007-06-27 15:18 ` Anton Altaparmakov
2007-06-27 22:35 ` David Chinner
2007-06-28 2:44 ` Nick Piggin
2007-06-28 12:20 ` Chris Mason
2007-06-29 2:08 ` David Chinner
2007-06-29 2:33 ` Nick Piggin
2007-06-30 11:05 ` Christoph Hellwig
2007-07-09 17:14 ` Christoph Lameter
2007-07-10 0:54 ` Nick Piggin
2007-07-10 0:59 ` Christoph Lameter
2007-07-10 1:07 ` Nick Piggin
2007-07-10 1:37 ` Dave McCracken
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