Re: CVS commit: src/sys/uvm

[Masao Uebayashi <uebayasi%tombi.co.jp@localhost>]

On Thu, Nov 25, 2010 at 04:18:25AM +0000, YAMAMOTO Takashi wrote:
> hi,
> 
> > Hi, thanks for review.
> > 
> > On Thu, Nov 25, 2010 at 01:58:04AM +0000, YAMAMOTO Takashi wrote:
> >> hi,
> >> 
> >> - what's VM_PHYSSEG_OP_PG?
> > 
> > It's to lookup vm_physseg by "struct vm_page *", relying on that
> > "struct vm_page *[]" is allocated linearly.  It'll be used to remove
> > vm_page::phys_addr as we talked some time ago.
> 
> i'm not sure if commiting this unused uncommented code now helps it.
> some try-and-benchmark cycles might be necessary given that
> vm_page <-> paddr conversion could be performace critical.

If you really care performance, we can directly pass "struct vm_page
*" to pmap_enter().

We're doing "struct vm_page *" -> "paddr_t" just before pmap_enter(),
then doing "paddr_t" -> "vm_physseg" reverse lookup again in
pmap_enter() to check if a given PA is managed.  What is really
needed here is, to lookup "struct vm_page *" -> "vm_physseg" once
and you'll know both paddr_t and managed or not.

> 
> YAMAMOTO Takashi

-- 
Masao Uebayashi / Tombi Inc. / Tel: +81-90-9141-4635