On Sun, Nov 02, 2008 at 10:39:10AM +0200, Avi Kivity wrote: > Marcelo Tosatti wrote: >> Err, I'm on crack. The assumption is that the common case is pte >> invalidation + invlpg: kunmap_atomic, page aging clearing the accessed >> bit, page reclaim. >> >> Linux COW will invalidate + invlpg (do_wp_page) first: >> >> entry = mk_pte(new_page, vma->vm_page_prot); >> entry = maybe_mkwrite(pte_mkdirty(entry), vma); >> /* >> * Clear the pte entry and flush it first, before >> * updating the >> * pte with the new entry. This will avoid a race >> * condition >> * seen in the presence of one thread doing SMC and >> * another >> * thread doing COW. >> */ >> ptep_clear_flush_notify(vma, address, page_table); >> >> Not sure about Windows. >> >> > > Okay, so Linux won't win on this. But is there any downside, apart from > fetching the pte and reestablishing the spte?
No, the downside is fetching the pte without being able to establish a valid spte. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
