Hi Rik
While being able to deal with used-once mappings in page reclaim could be a good idea, this would require us to be able to determine the difference between a page that was accessed once since it was faulted in and a page that got accessed several times.
it makes sense that read ahead hit assume used-once mapping, may be. I will try it. (may be, i can repost soon)
Given that page faults have overhead too, it does not surprise me that read+write is faster than mmap+memcpy. In threaded applications, page fault overhead will be worse still, since the TLBs need to be synchronized between CPUs (at least at reclaim time).
sure. but current is unnecessary large performance difference. I hope improvement it because copy by mmapd is very common operation.
Maybe we should just advise people to use read+write, since it is faster than mmap+memcpy?
Time is solved to it :) thanks! - kosaki
