Messages in this thread | | | Date | Fri, 10 Jun 2011 12:26:59 +0900 | From | KOSAKI Motohiro <> | Subject | Re: Change in functionality of futex() system call. |
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(2011/06/09 21:05), Peter Zijlstra wrote: > On Thu, 2011-06-09 at 20:37 +0900, KOSAKI Motohiro wrote: >> 1) check the pte of the target address is RW attribute. >> 2-1) if yes, it has no COW chance. we can safely use gup result. >> 2-2) if no, we have to fallback slow vma walk. maybe, it's okey. >> both RO mappings and COW are rare situation. > > Not so, clean file pages are RO, even if the vma is writable. We use the > fault to track dirty state with.
Right you are. Sigh. Please forget my previous mail.
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