Messages in this thread | | | Date | Fri, 18 Jan 2008 13:27:07 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: [PATCH -v6 2/2] Updating ctime and mtime for memory-mapped files |
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On Sat, 19 Jan 2008, Anton Salikhmetov wrote: > > Before using pte_wrprotect() the vma_wrprotect() routine uses the > pte_offset_map_lock() macro to get the PTE and to acquire the ptl > spinlock. Why did you say that this code was not SMP-safe? It should > be atomic, I think.
It's atomic WITH RESPECT TO OTHER PEOPLE WHO GET THE LOCK.
Guess how much another x86 CPU cares when it sets the accessed bit in hardware?
> The POSIX standard requires the ctime and mtime stamps to be updated > not later than at the second call to msync() with the MS_ASYNC flag.
.. and that is no excuse for bad code.
Linus
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