Subject: Re: M_EXT_PAGES
To: YAMAMOTO Takashi <>
From: Jason Thorpe <>
List: tech-kern
Date: 06/05/2004 13:50:14
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On Jun 5, 2004, at 12:47 AM, YAMAMOTO Takashi wrote:

> currently, ext_pgs is merely used as a hint for sodopendfreel().
> i'd like to change it to be used by bus_dmamap_load_mbuf() as well.
> (x86 diff is attached)

This is great; I wholeheartedly support this patch.  I intended this 
usage for ext_pgs, but simply never had a chance to implement this 

> while i think that the change itsself has its own benefits,
> eventual goals are:
> 	- delay pmap_kenter_pa() until it's really needed.
> 	  (likely on the first mtod()?)
> 	  if you're lucky enough, no pmap_kenter_pa() is needed at all.

Yes, this could really help both MP systems as well as systems with a 
virtually indexed cache.

> 	- use mbufs (or something similar) for disk i/o.

YES!  I would love to see mbuf chain support in the bio subsystem.  It 
could be especially helpful for network storage protocols (including 

         -- Jason R. Thorpe <>

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