On 03/02/2021 23:08, Peter Xu wrote: > As reported by Gal [1], we still miss the code clip to handle early cow for > > hugetlb case, which is true. Again, it still feels odd to fork() after using a > > few huge pages, especially if they're privately mapped to me.. However I do > > agree with Gal and Jason in that we should still have that since that'll > > complete the early cow on fork effort at least, and it'll still fix issues > > where buffers are not well under control and not easy to apply MADV_DONTFORK. > > > > The first two patches (1-2) are some cleanups I noticed when reading into the > > hugetlb reserve map code. I think it's good to have but they're not necessary > > for fixing the fork issue. > > > > The last two patches (3-4) is the real fix. > > > > I tested this with a fork() after some vfio-pci assignment, so I'm pretty sure > > the page copy path could trigger well (page will be accounted right after the > > fork()), but I didn't do data check since the card I assigned is some random > > nic. Gal, please feel free to try this if you have better way to verify the > > series. Thanks Peter, once v2 is submitted I'll pull the patches and we'll run the tests that discovered the issue to verify it works.
