On Tue, May 19, 2015 at 11:38 PM, Andrew Morton <a...@linux-foundation.org> wrote: > On Thu, 14 May 2015 19:30:57 +0200 Andrea Arcangeli <aarca...@redhat.com> > wrote: > >> This is the latest userfaultfd patchset against mm-v4.1-rc3 >> 2015-05-14-10:04. > > It would be useful to have some userfaultfd testcases in > tools/testing/selftests/. Partly as an aid to arch maintainers when > enabling this. And also as a standalone thing to give people a > practical way of exercising this interface. > > What are your thoughts on enabling userfaultfd for other architectures, > btw? Are there good use cases, are people working on it, etc?
UML is using SIGSEGV for page faults. i.e. the UML processes receives a SIGSEGV, learns the faulting address from the mcontext and resolves the fault by installing a new mapping. If userfaultfd is faster that the SIGSEGV notification it could speed up UML a bit. For UML I'm only interested in the notification, not the resolving part. The "missing" data is present, only a new mapping is needed. No copy of data. Andrea, what do you think? -- Thanks, //richard
