Invalidation sequences are handled in various ways on various
architectures.
One way, which sparc64 uses, is to let the set_*_at() functions accumulate
pending flushes into a per-cpu array. Then the flush_tlb_range() et al.
calls process the pending TLB flushes.
In this regime, the __tlb_remove_*tlb_entry() implementations are
essentially NOPs.
The canonical PTE zap in mm/memory.c is:
ptent = ptep_get_and_clear_full(mm, addr, pte,
tlb->fullmm);
tlb_remove_tlb_entry(tlb, pte, addr);
With a subsequent tlb_flush_mmu() if needed.
Mirror this in the THP PMD zapping using:
orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd);
page = pmd_page(orig_pmd);
tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
And we properly accomodate TLB flush mechanims like the one described
above.
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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