I would like to discuss your suggestion of moving the do_page_fault
instrumentation to handle_mm_fault. On one side, it helps removing architecture
dependant instrumentation, but on the other hand :
1- We cannot access the struct pt_regs in all cases (there may be an invalid
current task struct).
2- We cannot distinguish between calls to handle_mm_fault from the page fault
handler or from get_user_pages.
3- Some people complain about not having enough information about the cause of
the page fault (see the forward below).
So instead of staying between my users who ask for those feature and kernel
developers who wish to reduce the intrusiveness of instrumentation (which is a
nice goal : moving the syscall entry/exit instrumentation do do_syscall_trace
has helped simplifying the instrumentation), I prefer to open the discussion
about it.
Ideas/comments are welcome.
Regards,
Mathieu