Mention that other aliases should only arise from sharing or bugs.

diff --git a/doc/vm.texi b/doc/vm.texi
index 6f0c1a71b2e60b7cdeff0b8339580449426edb41..bc7fd46fa9e03719c47d763bb0c07b6045d489e0 100644 (file)
--- a/doc/vm.texi
+++ b/doc/vm.texi
@@ -213,6 +213,9 @@ could check and update the accessed and dirty bits for both addresses.
 Alternatively, the kernel could avoid the problem by only accessing user
 data through the user virtual address.
 
 Alternatively, the kernel could avoid the problem by only accessing user
 data through the user virtual address.
 

+Other aliases should only arise if you implement sharing, as extra
+credit (@pxref{VM Extra Credit}), or as bugs elsewhere in your code.
+

 @deftypefun bool pagedir_is_dirty (uint32_t *@var{pd}, const void *@var{vpage})
 @deftypefunx bool pagedir_is_accessed (uint32_t *@var{pd}, const void *@var{vpage})
 Returns true if page directory @var{pd} contains a page table entry for
 @deftypefun bool pagedir_is_dirty (uint32_t *@var{pd}, const void *@var{vpage})
 @deftypefunx bool pagedir_is_accessed (uint32_t *@var{pd}, const void *@var{vpage})
 Returns true if page directory @var{pd} contains a page table entry for


@@ -607,6 +610,7 @@ summary of project 2.
 Yes.
 
 @item What extra credit is available?
 Yes.
 
 @item What extra credit is available?

+@anchor{VM Extra Credit}

 
 You may implement sharing: when multiple processes are created that use
 the same executable file, share read-only pages among those processes
 
 You may implement sharing: when multiple processes are created that use
 the same executable file, share read-only pages among those processes