On Mon, Nov 21, 2011 at 05:00:04AM -0500, Christoph Hellwig wrote:

On Mon, Nov 21, 2011 at 05:18:20PM +0800, Wu Fengguang wrote:

quoted

Given that the non-rotational attribute is not always reported, we can
take disk size as a max readahead size hint. This patch uses a formula
that generates the following concrete limits:

Given that you mentioned the rotational flag and device size in this
mail, as well as benchmarking with an intel SSD  -  did you measure
how useful large read ahead sizes still are with highend Flash device
that have extremly high read IOP rates?

The more the IOPs the larger the "window" you need to keep everything
going I suspect.

-Andi
-- 
ak@linux.intel.com -- Speaking for myself only.

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