Messages in this thread | | | Date | Mon, 25 May 2020 14:42:41 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v6 1/4] MIPS: Do not flush tlb page when updating PTE entry |
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On Mon, 25 May 2020 10:52:37 +0800 Bibo Mao <maobibo@loongson.cn> wrote:
> It is not necessary to flush tlb page on all CPUs if suitable PTE > entry exists already during page fault handling, just updating > TLB is fine. > > Here redefine flush_tlb_fix_spurious_fault as empty on MIPS system. > > ... > > --- a/arch/mips/include/asm/pgtable.h > +++ b/arch/mips/include/asm/pgtable.h > @@ -478,6 +478,8 @@ static inline pgprot_t pgprot_writecombine(pgprot_t _prot) > return __pgprot(prot); > } > > +#define flush_tlb_fix_spurious_fault(vma, address) do { } while (0) > +
static inline C would be preferred, if that works. For a number of reasons:
- looks nicer
- more likely to get a code comment (for some reason)
- adds typechecking. So right now a MIPS developer could do
struct wibble a; struct wobble b;
flush_tlb_fix_spurious_fault(&a, &b);
and there would be no compiler warning. Then the code gets merged upstream and in come the embarrassing emails!
- avoids unused-var warnings
foo() { struct address_space a; struct vm_area_struct v;
flush_tlb_fix_spurious_fault(&v, &a); }
will generate unused-variable warnings if flush_tlb_fix_spurious_fault() is a macro. Making flush_tlb_fix_spurious_fault() inlined C prevents this.
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