Messages in this thread | | | From | Linus Torvalds <> | Date | Wed, 29 Aug 2018 16:15:37 -0700 | Subject | Re: [PATCH 2/3] mm/cow: optimise pte dirty/accessed bits handling in fork |
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On Wed, Aug 29, 2018 at 4:12 PM Nicholas Piggin <npiggin@gmail.com> wrote: > > Dirty micro fault seems to be the big one for my Skylake, takes 300 > nanoseconds per access. Accessed takes about 100. (I think, have to > go over my benchmark a bit more carefully and re-test).
Yeah, but they only happen for shared areas after fork, which sounds like it shouldn't be a big deal in most cases.
And I'm not entirely objecting to your patch per se, I just would want to keep the accessed bit changes separate from the dirty bit ones.
*If* somebody has bisectable issues with it (performance or not), it will then be clearer what the exact issue is.
Linus
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