Messages in this thread | | | Subject | Re: [PATCH] ppc64: Fix possible race with set_pte on a present PTE | From | Benjamin Herrenschmidt <> | Date | Wed, 26 May 2004 08:05:36 +1000 |
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On Wed, 2004-05-26 at 07:54, Linus Torvalds wrote: > On Wed, 26 May 2004, Benjamin Herrenschmidt wrote: > > > > Well, just setting one of those 2 bits doesn't require a hash table > > invalidate as long as nothing else changes. > > Ok. And nothing ever writes to the SW page tables outside the page table > lock, right? So on ppc64, we could just do > > #define ptep_update_dirty_accessed(ptep, entry, dirty) \ > *(ptep) = (entry) > > and be done with it. No? > > I'm not going to do it without a big ack from you.
No. The hash fault path will update the PTE dirty/accessed on a hash miss exception without holding the page table lock (acts a bit like a HW TLB as far as linux is concerned). That's why it needs to be atomic.
Ben.
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