Messages in this thread | | | Date | Tue, 13 Apr 2010 13:04:58 +0900 | Subject | Re: [PATCH 1/4] Simplify and comment on anon_vma re-use for anon_vma_prepare() | From | Minchan Kim <> |
| |
On Tue, Apr 13, 2010 at 5:22 AM, Linus Torvalds <torvalds@linux-foundation.org> wrote: > > From: Linus Torvalds <torvalds@linux-foundation.org> > Date: Sat, 10 Apr 2010 10:36:19 -0700 > Subject: [PATCH 1/4] Simplify and comment on anon_vma re-use for anon_vma_prepare() > > This changes the anon_vma reuse case to require that we only reuse > simple anon_vma's - ie the case when the vma only has a single anon_vma > associated with it. > > This means that a reuse of an anon_vma from an adjacent vma will always > guarantee that both vma's are associated not onyl with the same > anon_vma, they will also have the same anon_vma chain (of just a single > entry in this case). > > And since anon_vma re-use was the only case where the same anon_vma > might be associated with different chains of anon_vma's, we now have the > case that every vma that shares the same vma will always also have the
same vma => same anon_vma.
> same chain. That makes it much easier to think about merging vma's that > share the same anon_vma's: you can always just drop the other anon_vma > chain in anon_vma_merge() since you know that they are always identical. > > This also splits up the function to validate the anon_vma re-use, and > adds a lot of commentary about the possible races. > > Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
-- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |