| Message ID | 1653971769-14152-1-git-send-email-zhanghongchen@loongson.cn (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | MIPS: fix pmd_mkinvalid | expand |
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 <zhanghongchen@loongson.cn> > --- > 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 <zhanghongchen@loongson.cn> >> --- >> 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.
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; }
pmd_mkinvalid should not clear dirty flag,otherwise the pmd dirty flag,it's ok to just clear _PAGE_VALID. Signed-off-by: Hongchen Zhang <zhanghongchen@loongson.cn> --- arch/mips/include/asm/pgtable.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)