Messages in this thread | | | Date | Sat, 16 Feb 2008 21:54:41 +0200 | From | Avi Kivity <> | Subject | Re: [patch 3/6] mmu_notifier: invalidate_page callbacks |
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Christoph Lameter wrote: > On Fri, 15 Feb 2008, Andrew Morton wrote: > > >>> @@ -287,7 +288,8 @@ static int page_referenced_one(struct pa >>> if (vma->vm_flags & VM_LOCKED) { >>> referenced++; >>> *mapcount = 1; /* break early from loop */ >>> - } else if (ptep_clear_flush_young(vma, address, pte)) >>> + } else if (ptep_clear_flush_young(vma, address, pte) | >>> + mmu_notifier_age_page(mm, address)) >>> referenced++; >>> >> The "|" is obviously deliberate. But no explanation is provided telling us >> why we still call the callback if ptep_clear_flush_young() said the page >> was recently referenced. People who read your code will want to understand >> this. >> > > Andrea? > >
I'm not Andrea, but the way I read it, ptep_clear_flush_young() and ->age_page() each have two effects: check whether the page has been referenced and clear the referenced bit. || would retain the semantics of the check but lose the clearing. | does the right thing.
-- Any sufficiently difficult bug is indistinguishable from a feature.
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