svn commit: r254150 - head/sys/vm

[Alan Cox]

On Aug 9, 2013, at 1:34 PM, Alan Cox wrote:

> 
> On Aug 9, 2013, at 12:56 PM, John Baldwin wrote:
> 
>> On Friday, August 09, 2013 12:43:50 pm David E. O'Brien wrote:
>>> Author: obrien
>>> Date: Fri Aug  9 16:43:50 2013
>>> New Revision: 254150
>>> URL: http://svnweb.freebsd.org/changeset/base/254150
>>> 
>>> Log:
>>> Add missing 'VPO_BUSY' from r254141 to fix kernel build break.
>>> 
>>> Modified:
>>> head/sys/vm/vm_page.h
>> 
>> This can't possibly be correct as r254138 just removed this flag.  If it isn't 
>> obvious how to fix the uses added back in r254141, then r254141 should be 
>> reverted instead.
>> 
>> Hmm, looking at the relevant bits of r254141, it doesn't look obvious:
>> 
>> +       /* Detach the old page from the resident tailq. */
>> +       TAILQ_REMOVE(&object->memq, mold, listq);
>> +       vm_page_lock(mold);
> 
> Replace the next four lines with
> 
> 	vm_page_xunbusy(mold);
> 

On second thought, no, because it could lead to lock recursion.

>> +       if (mold->oflags & VPO_BUSY) {
>> +               mold->oflags &= ~VPO_BUSY;
>> +               vm_page_flash(mold);
>> +       }
>> 
>> Since nothing is setting this flag, this can't possibly work correctly 
>> currently.  I wouldn't boot a top-of-tree kernel right now. :(
>> 
>> -- 
>> John Baldwin
>> 
> 
>