Messages in this thread | | | Subject | Re: page fault scalability patch V12 [0/7]: Overview and performance tests | From | Benjamin Herrenschmidt <> | Date | Fri, 10 Dec 2004 16:06:16 +1100 |
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On Fri, 2004-12-10 at 15:54 +1100, Nick Piggin wrote: > Nick Piggin wrote: > > > Yep, the update_mmu_cache issue is real. There is a parallel problem > > that is update_mmu_cache can be called on a pte who's page has since > > been evicted and reused. Again, that looks safe on IA64, but maybe > > not on other architectures. > > > > It can be solved by moving lru_cache_add to after update_mmu_cache in > > all cases but the "update accessed bit" type fault. I solved that by > > simply defining that out for architectures that don't need it - a raced > > fault will simply get repeated if need be. > > > > The page-freed-before-update_mmu_cache issue can be solved in that way, > not the set_pte and update_mmu_cache not performed under the same ptl > section issue that you raised.
What is the problem with update_mmu_cache ? It doesn't need to be done in the same lock section since it's approx. equivalent to a HW fault, which doesn't take the ptl...
Ben.
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