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x86: revert "defer cr3 reload when doing pud_clear()"
Revert "defer cr3 reload when doing pud_clear()" since I'm going to replace it. Signed-off-by: Jeremy Fitzhardinge <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]>
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2 changed files with 6 additions and 22 deletions
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@ -96,23 +96,14 @@ static inline void pud_clear(pud_t *pudp)
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set_pud(pudp, __pud(0));
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/*
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* In principle we need to do a cr3 reload here to make sure
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* the processor recognizes the changed pgd. In practice, all
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* the places where pud_clear() gets called are followed by
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* full tlb flushes anyway, so we can defer the cost here.
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* Pentium-II erratum A13: in PAE mode we explicitly have to flush
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* the TLB via cr3 if the top-level pgd is changed...
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*
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* Specifically:
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*
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* mm/memory.c:free_pmd_range() - immediately after the
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* pud_clear() it does a pmd_free_tlb(). We change the
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* mmu_gather structure to do a full tlb flush (which has the
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* effect of reloading cr3) when the pagetable free is
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* complete.
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*
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* arch/x86/mm/hugetlbpage.c:huge_pmd_unshare() - the call to
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* this is followed by a flush_tlb_range, which on x86 does a
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* full tlb flush.
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* XXX I don't think we need to worry about this here, since
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* when clearing the pud, the calling code needs to flush the
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* tlb anyway. But do it now for safety's sake. - jsgf
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*/
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write_cr3(read_cr3());
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}
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#define pud_page(pud) \
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