Re: [PATCH] ppc64: Fix possible race with set_pte on a present PTE

[David Mosberger]

>>>>> On Tue, 25 May 2004 06:53:22 +0200, Andrea Arcangeli <andrea@xxxxxxx> said:

  >> If the "accessed" or "dirty" bits are zero, accessing/writing the
  >> page will cause a fault which will be handled in a low-level
  >> fault handler.  The Linux version of these handlers simply turn
  >> on the respective bit.  See daccess_bit(), iaccess_bit(), and dirty_bit()
  >> in arch/ia64/kernel/ivt.S.

  Andrea> so you mean, this is being set in the arch section before
  Andrea> ever reaching handle_mm_fault?

Correct.  The low-level fault handlers set the ACCESSED/DIRTY bits
with an atomic compare-and-exchange (on SMP).  They don't (normally)
bubble up all the way to the Linux page-fault handler.

	--david
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