svn commit: r233011 - head/sys/powerpc/aim

[Alan Cox]

On 3/15/2012 5:55 PM, Nathan Whitehorn wrote:
> On 03/15/12 17:18, Alan Cox wrote:
>> On 3/15/2012 2:36 PM, Nathan Whitehorn wrote:
>>> Author: nwhitehorn
>>> Date: Thu Mar 15 19:36:52 2012
>>> New Revision: 233011
>>> URL: http://svn.freebsd.org/changeset/base/233011
>>>
>>> Log:
>>>    Improve algorithm for deciding whether to loop through all 
>>> process pages
>>>    or look them up individually in pmap_remove() and apply the same 
>>> logic
>>>    in the other ranged operation (pmap_protect). This speeds up make
>>>    installworld by a factor of 2 on powerpc64.
>>>
>>>    MFC after:    1 week
>>>
>>> Modified:
>>>    head/sys/powerpc/aim/mmu_oea64.c
>>>
>>
>> As an additional, related optimization, you should look into 
>> implementing pmap_remove_pages().
>>
>> Alan
>>
>
> Thanks! I didn't know about that one. Is there a reason it isn't 
> called at the end of vm_pageout_map_deactivate_pages(), which seems to 
> deactivate all pages with pmap_remove()?

Yes, at least two reasons come to mind.  Some implementations only 
accept the caller's current pmap as an argument.  Also, there shouldn't 
be any other threads besides the caller using the pmap.