Re: [PATCH] mips/mm: Add page soft dirty tracking

[Jiaxun Yang]

ä 2020å4æ27æ GMT+08:00 äå12:54:42, Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> åå:
>On Tue, Apr 21, 2020 at 05:15:27PM +0800, Guoyun Sun wrote:
>> User space checkpoint and restart tool (CRIU) needs the page's change
>> to be soft tracked. This allows to do a pre checkpoint and then dump
>> only touched pages.
>> 
>> Signed-off-by: Guoyun Sun <sunguoyun@xxxxxxxxxxx>
>> ---
>>  arch/mips/Kconfig                    |  1 +
>>  arch/mips/include/asm/pgtable-bits.h |  8 ++++--
>>  arch/mips/include/asm/pgtable.h      | 48 ++++++++++++++++++++++++++++++++++--
>
>this breaks all 32bit builds where CPU support RIXI, because it overflows
>pgtable_bits.

Probably make a fixup patch to guard
_PAGE_SOFT_DIRTY_SHIFT with
CONFIG_HAVE_ARCH_SOFT_DIRTY
would be a better option?

Btw: It's really selfish that only enable SOFT_DIRTY for Loongson
but occupied a bit in pagetable for all MIPS systems.

I'd suggest select HAVE_ARCH_SOFT_DIRTY for all 64BIT MIPS systems.
Or provide config options to let expert users decide what feature they need.

Thanks.

>
>Thomas.
>

-- 
Jiaxun Yang