[RFC PATCH] mm: Fetch the dirty bit before we reset the pte

[Linus Torvalds]

On Thu, Oct 8, 2020 at 10:02 AM Linus Torvalds
<torvalds at linux-foundation.org> wrote:
>
> Here's the first patch anyway. If you actually have a test-case where
> this matters, I guess I need to apply it now..

Actually, I removed the "__page_mapcount()" part of that patch, to
keep it minimal and _only_ do remove the wrprotect trick.

We can do the __page_mapcount() optimization and the mm sequence count
for 5.10 (although so far nobody has actually written the seqcount
patch - I think it would be a trivial few-liner, but I guess it won't
make 5.10 at this point).

So here's what I ended up with.

                      Linus
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-mm-avoid-early-COW-write-protect-games-during-fork.patch
Type: text/x-patch
Size: 5138 bytes
Desc: not available
URL: <http://lists.ozlabs.org/pipermail/linuxppc-dev/attachments/20201008/75cdba6b/attachment-0001.bin>