Re: pmap_qenter() - the page *must* be wired - is violated

On Wed, Oct 5, 2011 at 4:53 PM, Kostik Belousov <kostikbel_at_gmail.com> wrote:
> On Wed, Oct 05, 2011 at 02:28:01PM +0200, Svatopluk Kraus wrote:
>> Hi,
>>
>>   I found out that on a few places pmap_qenter() is called on pages
>> which are not wired. For example, in the following functions, when
>> vm_pager_get_pages() is called, the pages are not wired:
>>
>>   exec_map_first_page() in sys/kern/kern_exec.c
>>   vm_fault_hold() in sys/vm/vm_fault.c
>>   vm_imgact_hold_page() in sys/vm/vm_glue.c
>>   vm_object_populate() in sys/vm/vm_object.c
>>   mdstart_swap() in sys/dev/md/md.c
>>
>>   Is the rule violated or the rule should be changed?
>
> Lets first discuss where did you found the calls to pmap_qenter().
> Can you point out exact line numbers of the calls to pmap_qenter()
> that you consider problematic ?
>
> In fact, the requirement probably shall be 'no swapout allowed'. E.g.,
> the busy page is fully qualified to be used together with pmap_qenter().

Well, I just follow description above pmap_qenter() blindly and test for
page wire_count inside the function. All function calls, I mentioned before,
are OK as pages are VPO_BUSY'd. Thanks for your explanation.

       Svata