The arm64 fork-then-swap-out-then-swap-in failures: a program source for exploring them

[Otacílio]

Em 10/04/2017 17:15, Mark Millard escreveu:
> On 2017-Apr-10, at 2:51 AM, Mark Millard <markmi at dsl-only.net> wrote:
>
>> On 2017-Apr-9, at 5:10 PM, Mark Millard <markmi at dsl-only.net> wrote:
>>
>>> On 2017-Apr-9, at 10:24 AM, Mark Millard <markmi at dsl-only.net> wrote:
>>>
>>>> On 2017-Apr-9, at 5:27 AM, Konstantin Belousov <kostikbel at gmail.com> wrote:
>>>>> Hmm, could you try the following patch, I did not even compiled it.
>>>> I'll try it later today.
>>>>
>>>>> diff --git a/sys/arm64/arm64/pmap.c b/sys/arm64/arm64/pmap.c
>>>>> index 3d5756ba891..55aa402eb1c 100644
>>>>> --- a/sys/arm64/arm64/pmap.c
>>>>> +++ b/sys/arm64/arm64/pmap.c
>>>>> @@ -2481,6 +2481,11 @@ pmap_protect(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, vm_prot_t prot)
>>>>> 		    sva += L3_SIZE) {
>>>>> 			l3 = pmap_load(l3p);
>>>>> 			if (pmap_l3_valid(l3)) {
>>>>> +				if ((l3 & ATTR_SW_MANAGED) &&
>>>>> +				    pmap_page_dirty(l3)) {
>>>>> +					vm_page_dirty(PHYS_TO_VM_PAGE(l3 &
>>>>> +					    ~ATTR_MASK));
>>>>> +				}
>>>>> 				pmap_set(l3p, ATTR_AP(ATTR_AP_RO));
>>>>> 				PTE_SYNC(l3p);
>>>>> 				/* XXX: Use pmap_invalidate_range */
>>>
>>> Preliminary testing indicates that this fixes the
>>> some-pages-become-zero problem for fork-then-swapout/in.
>>>
>>> Thanks!
>>>
>>> I'll see if a buildworld can go through without being stopped
>>> by the type of issue. But that will take a while. (It is how
>>> I originally ran into the problem(s) that others had been
>>> reporting on the lists.)
>> buildworld buildkernel completed non-stop for the first time
>> on a BPI-M3 board.
> I had been thinking of the BPI-M3 for other reasons
> and typed that instead of the correct: Pine64+ 2GB.
> (True elsewhere as well.) I do really mean arm64
> here, not armv7.
>
>> Looks good for a check-in to svn to me (head and stable/11).
>>
>> This combined with 2017-Feb-15's -r313772's fix to the fork
>> trampline code's updating of sp_el0 makes arm64 far more stable
>> for my purposes.
>>
>> -r313772 was never MFC'd to stable/11. In my view it should be.
> ===
> Mark Millard
> markmi at dsl-only.net
>
Dears

Will this patch be committed to HEAD?

[]'s
-Otacilio