Signed-off-by: Mike Rapoport <r...@linux.vnet.ibm.com> --- man2/userfaultfd.2 | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2 index 8b89162..f177bba 100644 --- a/man2/userfaultfd.2 +++ b/man2/userfaultfd.2 @@ -112,6 +112,18 @@ created for the child process, which allows userfaultfd monitor to perform user-space paging for the child process. +Unlike page faults which have to be synchronous and require +explicit or implicit wakeup, +all other events are delivered asynchronously and +the non-cooperative process resumes execution as +soon as manager executes +.BR read(2). +The userfaultfd manager should carefully synchronize calls +to UFFDIO_COPY with the events processing. + +The current asynchronous model of the event delivery is optimal for +single threaded non-cooperative userfaultfd manager implementations. + .\" FIXME elaborate about non-cooperating mode, describe its limitations .\" for kernels before 4.11, features added in 4.11 .\" and limitations remaining in 4.11 -- 1.9.1
