Messages in this thread | | | Date | Mon, 28 Sep 2020 13:13:21 -0400 | From | Peter Xu <> | Subject | Re: [PATCH 1/5] mm: Introduce mm_struct.has_pinned |
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On Sun, Sep 27, 2020 at 11:16:34AM -0700, Linus Torvalds wrote: > - split up the "copy page" into its own function kind of like I had > done for my minimal patch
I didn't do that majorly because of the wrprotect() (of the fast-gup race) that can potentially be kept if it's a normal cow. Maybe we'd add one more comment above the caller of copy_present_page() (even if we have a "NOTE!" section already inside the helper) since it'll change *src_pte and it's hard to notice from the function name "copy_present_page()". Not that important, though.
Thanks for doing the changes. I went over the whole patch and it looks indeed cleaner than before (I also didn't spot anything wrong either).
Regarding the other even rarer "hardware race on dirty/access bits" - maybe we can simply set all these two bits always when page copy happens and we want to recover the ptes? I also agree it's trivial enough, so that maybe we even don't need to care about that.
-- Peter Xu
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