在 2022/5/31 5:36, Hongchen Zhang 写道:
> pmd_mkinvalid should not clear dirty flag,otherwise the pmd
> dirty flag,it's ok to just clear _PAGE_VALID.
Hi Hongcheng,
Sorry, what is meant by "otherwise the pmd dirty flag"? Could you please
elaborate?
In my humble opinion _PAGE_PRESENT must be cleared in mkinvalid as it
nolonger present here. And thus it lose the dirty status.
Thanks
- Jiaxun
> Signed-off-by: Hongchen Zhang <[email protected]>
> ---
> arch/mips/include/asm/pgtable.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
> index 374c632..d30a186 100644
> --- a/arch/mips/include/asm/pgtable.h
> +++ b/arch/mips/include/asm/pgtable.h
> @@ -698,7 +698,7 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
>
> static inline pmd_t pmd_mkinvalid(pmd_t pmd)
> {
> - pmd_val(pmd) &= ~(_PAGE_PRESENT | _PAGE_VALID | _PAGE_DIRTY);
> + pmd_val(pmd) &= ~_PAGE_VALID;
>
> return pmd;
> }
On 2022/5/31 下午11:40, Jiaxun Yang wrote:
>
>
> 在 2022/5/31 5:36, Hongchen Zhang 写道:
>> pmd_mkinvalid should not clear dirty flag,otherwise the pmd
>> dirty flag,it's ok to just clear _PAGE_VALID.
> Hi Hongcheng,
>
> Sorry, what is meant by "otherwise the pmd dirty flag"? Could you please
> elaborate?
> In my humble opinion _PAGE_PRESENT must be cleared in mkinvalid as it
> nolonger present here. And thus it lose the dirty status.
>
> Thanks
> - Jiaxun
>
>> Signed-off-by: Hongchen Zhang <[email protected]>
>> ---
>> arch/mips/include/asm/pgtable.h | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/mips/include/asm/pgtable.h
>> b/arch/mips/include/asm/pgtable.h
>> index 374c632..d30a186 100644
>> --- a/arch/mips/include/asm/pgtable.h
>> +++ b/arch/mips/include/asm/pgtable.h
>> @@ -698,7 +698,7 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t
>> newprot)
>> static inline pmd_t pmd_mkinvalid(pmd_t pmd)
>> {
>> - pmd_val(pmd) &= ~(_PAGE_PRESENT | _PAGE_VALID | _PAGE_DIRTY);
>> + pmd_val(pmd) &= ~_PAGE_VALID;
>> return pmd;
>> }
Hi Jiaxun,
Refer to [ https://lkml.org/lkml/2018/10/17/231 ],Andrea said "
The clear of the real present bit during pmd (virtual) splitting is
done with pmdp_invalidate, that is created specifically to keeps
pmd_trans_huge=true, pmd_present=true despite the present bit is not
set. ". So it's wrong to clear _PAGE_PRESENT,because this will make
pmd_present=false.
On the other hand, There is no need to clear dirty flag too.
Thanks.