lkml.org 
[lkml]   [2010]   [Apr]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH -v2] rmap: make anon_vma_prepare link in all the anon_vmas of a mergeable VMA
    On 04/12/2010 11:44 AM, Linus Torvalds wrote:
    > On Sun, 11 Apr 2010, Rik van Riel wrote:
    >>
    >> Looking around the code some more, zap_pte_range()
    >> calls page_remove_rmap(), which leaves the
    >> page->mapping in place and has this comment:
    >
    > See my earlier email about this exact issue. It's well-known that there
    > are stale page->mapping pointers. The "page_mapped()" check _should_ have
    > meant that in that case we never follow them, though.

    Good point. I wonder if we have some SMP reordering
    issue then?

    >> I wonder if we can clear page->mapping here, if
    >> list_is_singular(anon_vma->head). That way we
    >> will not leave stale pointers behind.
    >
    > What does that help? What if list _isn't_ singular?

    Yeah, that was a bad idea. Looking at the same code for
    11 days straight seems to have put some knots in my brain :)


    \
     
     \ /
      Last update: 2010-04-12 17:55    [W:6.480 / U:0.020 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site