Messages in this thread | | | Date | Thu, 14 May 2020 12:33:59 +0300 | From | Mike Rapoport <> | Subject | Re: [PATCH] MIPS: update tlb even if pte entry has no change |
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On Thu, May 14, 2020 at 10:17:57AM +0800, Bibo Mao wrote: > From: bibo mao <maobibo@loongson.cn> > > If there are two threads reading the same memory and tlb miss happens, > one thread fills pte entry, the other reads new pte value during page fault > handling. PTE value may be updated before page faul, so the process need > need update tlb still. > > Also this patch define flush_tlb_fix_spurious_fault as empty, since it not > necessary to flush the page for all CPUs
I'm not familiar enough with MIPS TLB workings, but it seems that adding a MIPS version of ptep_set_access_flags() and relaxing flush_tlb_fix_spurious_fault() are two separate patches.
> Signed-off-by: Bibo Mao <maobibo@loongson.cn> > --- > arch/mips/include/asm/pgtable.h | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h > index aab0ec1..d0a4940 100644 > --- a/arch/mips/include/asm/pgtable.h > +++ b/arch/mips/include/asm/pgtable.h > @@ -635,6 +635,26 @@ static inline pmd_t pmd_mknotpresent(pmd_t pmd) > return pmd; > } > > +#define flush_tlb_fix_spurious_fault(vma, address) do { } while (0) > + > +#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS > +int ptep_set_access_flags(struct vm_area_struct *vma, > + unsigned long address, pte_t *ptep, > + pte_t entry, int dirty) > +{ > + int changed = !pte_same(*ptep, entry); > + > + if (changed) > + set_pte_at(vma->vm_mm, address, ptep, entry); > + else > + /* update tlb with latest pte entry still, tlb entry is old > + * since there is page fault > + */ > + update_mmu_cache(vma, address, ptep); > + > + return changed; > +} > + > /* > * The generic version pmdp_huge_get_and_clear uses a version of pmd_clear() with a > * different prototype. > -- > 1.8.3.1 >
-- Sincerely yours, Mike.
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