Messages in this thread | | | Date | Thu, 31 Jan 2008 17:48:19 -0800 (PST) | From | Christoph Lameter <> | Subject | Re: mmu_notifier: close hole in fork |
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On Fri, 1 Feb 2008, Andrea Arcangeli wrote:
> Good catch! This was missing also in my #v5 (KVM doesn't need that > because the only possible cows on sptes can be generated by ksm, but > it would have been a problem for GRU). The more I think about it, the
How do you think the GRU should know when to drop the refcount? There is no page table and thus no way of tracking that a refcount was taken. Without the refcount you cannot defer the freeing of the page. So shootdown on invalidate_range_begin and lock out until invalidate_range_end seems to be the only workable solution.
BTW what do you think about adding a flag parameter to the invalidate calls that allows shooting down writable ptes only? That could be useful for COW and page_mkclean.
So
#define MMU_ATOMIC 1 #define MMU_WRITABLE 2
insted of the atomic parameter?
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