Re: [PATCH 15/18] mm, hugetlb: move up anon_vma_prepare()

From: Naoya Horiguchi
Date: Wed Jul 31 2013 - 12:44:24 EST


On Wed, Jul 31, 2013 at 02:12:21PM +0900, Joonsoo Kim wrote:
> On Mon, Jul 29, 2013 at 03:19:15PM -0400, Naoya Horiguchi wrote:
> > On Mon, Jul 29, 2013 at 03:05:37PM -0400, Naoya Horiguchi wrote:
> > > On Mon, Jul 29, 2013 at 02:32:06PM +0900, Joonsoo Kim wrote:
> > > > If we fail with a allocated hugepage, it is hard to recover properly.
> > > > One such example is reserve count. We don't have any method to recover
> > > > reserve count. Although, I will introduce a function to recover reserve
> > > > count in following patch, it is better not to allocate a hugepage
> > > > as much as possible. So move up anon_vma_prepare() which can be failed
> > > > in OOM situation.
> > > >
> > > > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> > >
> > > Reviewed-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> >
> > Sorry, let me suspend this Reviewed for a question.
> > If alloc_huge_page failed after we succeeded anon_vma_parepare,
> > the allocated anon_vma_chain and/or anon_vma are safely freed?
> > Or don't we have to free them?
>
> Yes, it will be freed by free_pgtables() and then unlink_anon_vmas()
> when a task terminate. So, we don't have to free them.

OK, thanks for clarification.

Reviewed-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
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