[lkml]   [2010]   [May]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH 3/5] track the root (oldest) anon_vma
On Wed, 12 May 2010 13:39:58 -0400
Rik van Riel <> wrote:

> Subject: track the root (oldest) anon_vma
> Track the root (oldest) anon_vma in each anon_vma tree. Because we only
> take the lock on the root anon_vma, we cannot use the lock on higher-up
> anon_vmas to lock anything. This makes it impossible to do an indirect
> lookup of the root anon_vma, since the data structures could go away from
> under us.
> However, a direct pointer is safe because the root anon_vma is always the
> last one that gets freed on munmap or exit, by virtue of the same_vma list
> order and unlink_anon_vmas walking the list forward.
> Signed-off-by: Rik van Riel <>

Acked-by: KAMEZAWA Hiroyuki <>

I welcome this. Thank you!

Reading 4/5, I felt I'm grad if you add a Documentation or very-precise-comment
about the new anon_vma rules and the _meaning_ of anon_vma_root_lock.
I cannot fully convice myself that I understand them all.

 \ /
  Last update: 2010-05-13 02:45    [W:0.046 / U:1.596 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site