Am 13.05.2017 um 12:04 schrieb Richard Weinberger: > Thomas, Hi,
> On Sat, May 13, 2017 at 10:10 AM, Thomas Meyer <tho...@m3y3r.de> wrote: >> >> Hi, >> >> after looking into using userfaultfd for the userspace UML process >> page fault handling, I come to the conclusion that userfaultfd >> *cannot* be used for above goal as it only operates on mmaped memory >> areas. >> Am I missing something? What do you think about it? > > See: https://lkml.org/lkml/2015/5/20/541 Cool! Thanks for the hint. I don't follow LKML, so... But Andrea wrote: "Alternatively once we extend the handle_userfault to tmpfs you could map the page in two virtual mappings and track the faults in one mapping (where the tracked app runs) and read/write the page contents in the other mapping that isn't tracked by the userfault." I think this is now the case with 4.11, isn't it? As I understand this we must do the following: kernel process: Map a tmpfs region for each userspace process with read/write. userspace process: Map the same tmpfs for the current process and userfaultfd the whole address space, and give the userfaultfd fd to the kernel somehow and process the page fault there and fill/copy the faulted page accordingly. so each userspace process would be backed by a tmpfs mmap region? sound complicated. with kind regards thomas ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
