Messages in this thread | | | Date | Wed, 12 May 2010 22:25:15 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH 3/5] track the root (oldest) anon_vma |
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On 05/12/2010 08:38 PM, KAMEZAWA Hiroyuki wrote: > On Wed, 12 May 2010 13:39:58 -0400 > Rik van Riel<riel@redhat.com> 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<riel@redhat.com> > > > Acked-by: KAMEZAWA Hiroyuki<kamezawa.hiroyu@jp.fujitsu.com> > > 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.
Please send me a list of all the questions that come up when you read the patches, and I'll prepare a patch 6/5 with just documentation :)
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