Date: Mon, 10 Apr 2017 02:51:39 -0700 From: Mark Millard <markmi@dsl-only.net> To: Konstantin Belousov <kostikbel@gmail.com> Cc: andrew@freebsd.org, freebsd-hackers@freebsd.org, freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: The arm64 fork-then-swap-out-then-swap-in failures: a program source for exploring them Message-ID: <585B43F7-D4C8-431A-BFFE-68B48C3214AE@dsl-only.net> In-Reply-To: <89D6D677-3BE2-45E2-A902-CC6A0305F3F9@dsl-only.net> References: <4DEA2D76-9F27-426D-A8D2-F07B16575FB9@dsl-only.net> <163B37B0-55D6-498E-8F52-9A95C036CDFA@dsl-only.net> <08E7A5B0-8707-4479-9D7A-272C427FF643@dsl-only.net> <20170409122715.GF1788@kib.kiev.ua> <9D152170-5F19-47A2-A06A-66F83CA88A09@dsl-only.net> <9DCAF95B-39A5-4346-88FC-6AFDEE8CF9BB@dsl-only.net> <8FFE95AA-DB40-4D1E-A103-4BA9FCC6EDEE@dsl-only.net> <89D6D677-3BE2-45E2-A902-CC6A0305F3F9@dsl-only.net>
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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:
>=20
>> On 2017-Apr-9, at 5:27 AM, Konstantin Belousov <kostikbel@gmail.com> =
wrote:
>=20
>>=20
>>> Hmm, could you try the following patch, I did not even compiled it.
>>=20
>> I'll try it later today.
>>=20
>>> 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 +=3D L3_SIZE) {
>>> l3 =3D 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 */
>=20
>=20
> Preliminary testing indicates that this fixes the
> some-pages-become-zero problem for fork-then-swapout/in.
>=20
> Thanks!
>=20
> 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.
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.
=3D=3D=3D
Mark Millard
markmi at dsl-only.net
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