Re: [Squashfs-devel] [PATCH 0/2] squashfs: support linear addressing

[UCHINO S. <sat...@to...>]

Hi,

On Tue, 15 May 2012 22:02:22 +0900, "Vyacheslav Dubeyko" <sl...@du...> wrote:
> Hi,
> 
> Could you please describe in more details advantages of your patchset?
> Do you have any benchmark results?

Though this is quite old material (6 years old :), 
here is our presentation material at CELF Japan Jamboree #6.
(http://tree.celinuxforum.org/CelfPubWiki/JapanTechnicalJamboree6)

(Slide in Japanese)
http://tree.celinuxforum.org/CelfPubWiki/JapanTechnicalJamboree6?action=AttachFile&do=view&target=squashfs_jpn.pdf

(English translation)
http://tree.celinuxforum.org/CelfPubWiki/JapanTechnicalJamboree6?action=AttachFile&do=view&target=squashfs_eng.pdf

See pages 12-15 in particular.

In this benchmark, we copied initrd image to ram disk.
Now, we probably have better way to do so and performance improvement
will get much smaller.

However, for the use case of mounting image in arbitrary physical
address range, we believe this solution is much more straightfoward
than using block devices.

Best regards,
  UCHINO Satoshi


> On Tue, 2012-05-15 at 20:33 +0900, UCHINO Satoshi wrote:
>> This patchset enables the SquashFS driver to load data directly from a
>> linear adressed memory range (usually non volatile memory like flash)
>> instead of going through the block device layer.  This saves some
>> memory since no intermediate buffering is necessary.
>>
>> The location of the SquashFs image need to be specified by using the
>> physaddr=0x******** mount option.
>> For example,
>>   mount -t squashfs_linear -o physaddr=0x100000 none /mnt
>>
>> In addition, the linear SquashFS image can be used as a root file
>> system.  To actually have the kernel mount this SquashFS image as a
>> root file system, you must also pass the command line parameter
>> "root=/dev/null", "rootfstype=squashfs_linear", and
>> "rootflags=physaddr=0x********" to the kernel (replace 0x******** with
>> the physical address location of the linear SquashFs image to boot
>> with).
>>
>> UCHINO Satoshi (2):
>>   squashfs: add an extra argument to decompress callback
>>   squashfs: support linear addressing
>>
>>  fs/squashfs/Kconfig          |   25 +++++++
>>  fs/squashfs/block.c          |   72 ++++++++++++++++++---
>>  fs/squashfs/decompressor.h   |    6 +-
>>  fs/squashfs/inode.c          |   10 +++
>>  fs/squashfs/lzo_wrapper.c    |   12 +++-
>>  fs/squashfs/squashfs.h       |    5 ++
>>  fs/squashfs/squashfs_fs_sb.h |    2 +
>>  fs/squashfs/super.c          |  144 
>> +++++++++++++++++++++++++++++++++++++++---
>>  fs/squashfs/xz_wrapper.c     |    7 ++-
>>  fs/squashfs/zlib_wrapper.c   |    7 ++-
>>  10 files changed, 265 insertions(+), 25 deletions(-)