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From: Charles Manning <manningc2@actrix.gen.nz>
To: Ryan Mallon <ryan@bluewatersys.com>
Cc: Charles Manning <cdhmanning@gmail.com>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	akpm@linux-foundation.org
Subject: Re: [PATCH 09/10] Add yaffs2 file system: Linux glue code
Date: Fri, 11 Feb 2011 11:47:02 +1300	[thread overview]
Message-ID: <201102111147.03100.manningc2@actrix.gen.nz> (raw)
In-Reply-To: <4D5461A3.2040703@bluewatersys.com>

On Friday 11 February 2011 11:07:31 Ryan Mallon wrote:
> On 02/09/2011 04:26 PM, Charles Manning wrote:
> > Signed-off-by: Charles Manning <cdhmanning@gmail.com>
>
> Hi Charles,
>
> More comments below. The locking I think needs some work before this is
> okay for mainline. It would be interesting to stress test yaffs on an
> SMP machine. None of the boards which we run yaffs on are though :-(.

yaffs can be run on a PC using nandsim and I have done so with the 
multi-version code. I am setting up another PC for single-version (ie. 
mainlining) testing.

I'll take an in depth look at your comments, but it is important to understand 
the locking model a bit better,

yaffs just uses one big lock. We need to consider locking for many reasons and 
need to ensure that stuff does not get modified behind our back. For example 
setattr on one object can cause garbage collection to change the flash 
location - and thus the tnode tree - of another object.

There is probably scope to change the gross locking model to a r/w lock which 
would mean that read operations could proceed better.

I did a non-open-source project of looking at finer grained locking but found 
that there were not many gains for what I looked at. Ultimately anything that 
goes to flash is serialised by the flash access.

-- Charles

  reply	other threads:[~2011-02-10 22:47 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-09  3:25 [PATCH 0/10] Add yaffs2 file system: Fifth patchset Charles Manning
2011-02-09  3:25 ` [PATCH 01/10] Add yaffs2 file system: allocators, bitmap and block handling Charles Manning
2011-02-09  3:26 ` [PATCH 02/10] Add yaffs2 file system: attrib and xattrib handling Charles Manning
2011-02-09 22:33   ` Ryan Mallon
2011-02-09  3:26 ` [PATCH 03/10] Add yaffs2 file system: checkpoint streaming Charles Manning
2011-02-10 22:27   ` Jesper Juhl
2011-02-10 22:44     ` Ryan Mallon
2011-02-10 22:50       ` Charles Manning
2011-02-09  3:26 ` [PATCH 04/10] Add yaffs2 file system: flash interface and ecc handling Charles Manning
2011-02-09  3:26 ` [PATCH 05/10] Add yaffs2 file system: tags handling Charles Manning
2011-02-09  3:26 ` [PATCH 06/10] Add yaffs2 file system: tracing and verification handling Charles Manning
2011-02-11 23:01   ` Ryan Mallon
2011-02-09  3:26 ` [PATCH 07/10] Add yaffs2 file system: yaffs1 and yaffs2 mode handling Charles Manning
2011-02-09  3:26 ` [PATCH 08/10] Add yaffs2 file system: core guts code Charles Manning
2011-02-10  2:27   ` Ryan Mallon
2011-02-09  3:26 ` [PATCH 09/10] Add yaffs2 file system: Linux glue code Charles Manning
2011-02-10 22:07   ` Ryan Mallon
2011-02-10 22:47     ` Charles Manning [this message]
2011-02-17 22:24   ` Ryan Mallon
2011-02-09  3:26 ` [PATCH 10/10] Add yaffs2 file system: hok in to Linux tree Charles Manning
2011-02-09  4:52 ` [PATCH 0/10] Add yaffs2 file system: Fifth patchset Christoph Hellwig
2011-02-09 18:22   ` Charles Manning
2011-02-16  8:04     ` Christoph Hellwig
2011-02-16 22:12       ` Charles Manning
2011-02-17  1:48         ` Mark Brown
2011-02-17  2:31           ` Charles Manning
2011-02-17  2:52             ` Ryan Mallon
2011-02-17  3:49               ` Charles Manning
2011-02-17 23:41                 ` Greg KH
2011-02-18  0:01                   ` Mark Brown
2011-02-18  0:33                     ` Greg KH
2011-02-18  0:43                       ` Mark Brown
2011-02-18  0:55                         ` Ryan Mallon
2011-02-18  0:58                           ` Greg KH
2011-02-20 17:25                             ` Charles Manning
2011-02-20 20:07                               ` Greg KH
2011-02-20 20:52                                 ` Ryan Mallon
2011-02-20 22:29                                   ` Greg KH
2011-02-20 22:57                                     ` Ryan Mallon
2011-02-18  1:08                           ` Mark Brown
2011-02-17  3:49             ` Mark Brown
2011-02-17  4:22               ` Charles Manning
2011-02-17  6:08                 ` Mark Brown
2011-02-19 17:45         ` Pavel Machek
2011-08-17 12:12 ` Linus Walleij
  -- strict thread matches above, loose matches on Subject: below --
2011-01-14  3:05 [PATCH 0/10] Add yaffs2 file system: Fourth patchset Charles Manning
2011-01-14  3:06 ` [PATCH 09/10] Add yaffs2 file system: Linux glue code Charles Manning
2011-01-20 20:14   ` Jesper Juhl
2011-01-20 21:26   ` Ryan Mallon

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