Date: Thu, 6 Oct 2011 13:45:16 +0200 From: Svatopluk Kraus <onwahe@gmail.com> To: Kostik Belousov <kostikbel@gmail.com> Cc: freebsd-current@freebsd.org Subject: Re: pmap_qenter() - the page *must* be wired - is violated Message-ID: <CAFHCsPUjdxW2w%2BN2hyS8FTOEKFFXjyLHxV47-iW9WdQMK1NRqg@mail.gmail.com> In-Reply-To: <20111005145333.GD1511@deviant.kiev.zoral.com.ua> References: <CAFHCsPX2dzv9Hk-WM_%2BQj%2BovihQZs17y=Guouj8t-3T_nQtLXw@mail.gmail.com> <20111005145333.GD1511@deviant.kiev.zoral.com.ua>
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On Wed, Oct 5, 2011 at 4:53 PM, Kostik Belousov <kostikbel@gmail.com> wrote=
:
> On Wed, Oct 05, 2011 at 02:28:01PM +0200, Svatopluk Kraus wrote:
>> Hi,
>>
>> =A0 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:
>>
>> =A0 exec_map_first_page() in sys/kern/kern_exec.c
>> =A0 vm_fault_hold() in sys/vm/vm_fault.c
>> =A0 vm_imgact_hold_page() in sys/vm/vm_glue.c
>> =A0 vm_object_populate() in sys/vm/vm_object.c
>> =A0 mdstart_swap() in sys/dev/md/md.c
>>
>> =A0 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
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