On Fri, 29 May 2009 14:35:55 +0900 Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp> wrote:

> I added blk_run_backing_dev on page_cache_async_readahead
> so readahead I/O is unpluged to improve throughput on 
> especially RAID environment. 

I skipped the last version of this because KOSAKI Motohiro
<kosaki.motohiro@jp.fujitsu.com> said "Please attach blktrace analysis ;)".

I'm not sure why he asked for that, but he's a smart chap and
presumably had his reasons.

If you think that such an analysis is unneeded, or isn't worth the time
to generate then please tell us that.  But please don't just ignore the
request!

Thanks.