Messages in this thread | | | Date | Thu, 29 Aug 2002 18:46:15 -0300 (BRT) | From | Rik van Riel <> | Subject | Re: [PATCH] low-latency zap_page_range() |
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On Thu, 29 Aug 2002, Andrew Morton wrote:
> > So we know it is held forever and a day... but is there contention? > > I'm sure there is, but nobody has measured the right workload. > > Two CLONE_MM threads, one running mmap()/munmap(), the other trying > to fault in some pages. I'm sure someone has some vital application > which does exactly this. They always do :(
Can't fix this one. The mmap()/munmap() needs to have the mmap_sem for writing as long as its setting up or tearing down a VMA while the pagefault path takes the mmap_sem for reading.
It might be fixable in some dirty way, but I doubt that'll ever be worth it.
regards,
Rik -- Bravely reimplemented by the knights who say "NIH".
http://www.surriel.com/ http://distro.conectiva.com/
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