Jffs2 and big file = very slow jffs2_garbage_collect_pass

[Josh Boyer]

On Fri, 18 Jan 2008 17:17:34 +0100
Matthieu CASTET <matthieu.castet at parrot.com> wrote:
 
> I sent a mail, but  because of Message has a suspicious header, the 
> message wait  moderator approval.
> 
> 
> In summary,
> the code spend lot's of time in the rbtree code (7 minutes) and 4 
> minutes in jffs2_get_inode_nodes.
> 
> 
> Matthieu
> 
> 
>   54366 rb_prev                                  543,6600
>   28345 rb_next                                  283,4500
>    8602 default_idle                              71,6833
>   10251 __raw_readsl                              40,0430
>   49648 jffs2_get_inode_nodes                     11,8097
>     251 s3c2412_nand_devready                      7,8438
>    1222 crc32_le                                   4,8492

That seems consistent with JFFS2 doing the CRC checks and constructing
the in-memory representation of your large file.  I suspect the older
list-based in-memory implementation would have taken even longer, but
there could be something amiss with the rb-tree stuff perhaps.

josh