Messages in this thread | | | Date | Sun, 25 Mar 2007 23:35:53 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [patch -mm 1/2] i386: add ptep_test_and_clear_{dirty,young} |
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On Sun, 25 Mar 2007, Zachary Amsden wrote:
> If you actually clear the bit, you need to: > > + pte_update_defer(vma->vm_mm, addr, ptep); > > The reason is, when updating PTEs, the hypervisor must be notified. Using > atomic operations to do this is fine for all hypervisors I am aware of. > However, for hypervisors which shadow page tables, if these PTE modifications > are not trapped, you need a post-modification call to fulfill the update of > the shadow page table. >
Then why was ptep_test_and_clear_{dirty,young} ever removed in the first place?? To gain the optimization of one fewer branch and introduce a hack to advertise it's existance so the generic header file doesn't include its own version? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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