Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-09-05 Thread Michal Hocko
On Tue 04-09-18 10:00:36, Jerome Glisse wrote: > On Mon, Sep 03, 2018 at 07:56:54AM +0200, Michal Hocko wrote: [...] > > And THP migration is still a problem with 4.4 AFAICS. All other cases > > simply split the huge page but THP migration keeps it in one piece and > > as such it is theoretically

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-09-05 Thread Michal Hocko
On Tue 04-09-18 10:00:36, Jerome Glisse wrote: > On Mon, Sep 03, 2018 at 07:56:54AM +0200, Michal Hocko wrote: [...] > > And THP migration is still a problem with 4.4 AFAICS. All other cases > > simply split the huge page but THP migration keeps it in one piece and > > as such it is theoretically

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-09-04 Thread Mike Kravetz
On 09/04/2018 07:00 AM, Jerome Glisse wrote: > On Mon, Sep 03, 2018 at 07:56:54AM +0200, Michal Hocko wrote: >> On Thu 30-08-18 14:39:44, Jerome Glisse wrote: >>> For all intents and purposes this is not a backport of the original >>> patch so maybe we should just drop the commit reference and

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-09-04 Thread Mike Kravetz
On 09/04/2018 07:00 AM, Jerome Glisse wrote: > On Mon, Sep 03, 2018 at 07:56:54AM +0200, Michal Hocko wrote: >> On Thu 30-08-18 14:39:44, Jerome Glisse wrote: >>> For all intents and purposes this is not a backport of the original >>> patch so maybe we should just drop the commit reference and

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-09-04 Thread Jerome Glisse
On Mon, Sep 03, 2018 at 07:56:54AM +0200, Michal Hocko wrote: > On Thu 30-08-18 14:39:44, Jerome Glisse wrote: > > On Thu, Aug 30, 2018 at 11:05:16AM -0700, Mike Kravetz wrote: > > > On 08/30/2018 09:57 AM, Jerome Glisse wrote: > > > > On Thu, Aug 30, 2018 at 06:19:52PM +0200, Michal Hocko wrote:

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-09-04 Thread Jerome Glisse
On Mon, Sep 03, 2018 at 07:56:54AM +0200, Michal Hocko wrote: > On Thu 30-08-18 14:39:44, Jerome Glisse wrote: > > On Thu, Aug 30, 2018 at 11:05:16AM -0700, Mike Kravetz wrote: > > > On 08/30/2018 09:57 AM, Jerome Glisse wrote: > > > > On Thu, Aug 30, 2018 at 06:19:52PM +0200, Michal Hocko wrote:

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-09-02 Thread Michal Hocko
On Thu 30-08-18 14:39:44, Jerome Glisse wrote: > On Thu, Aug 30, 2018 at 11:05:16AM -0700, Mike Kravetz wrote: > > On 08/30/2018 09:57 AM, Jerome Glisse wrote: > > > On Thu, Aug 30, 2018 at 06:19:52PM +0200, Michal Hocko wrote: > > >> On Thu 30-08-18 10:08:25, Jerome Glisse wrote: > > >>> On Thu,

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-09-02 Thread Michal Hocko
On Thu 30-08-18 14:39:44, Jerome Glisse wrote: > On Thu, Aug 30, 2018 at 11:05:16AM -0700, Mike Kravetz wrote: > > On 08/30/2018 09:57 AM, Jerome Glisse wrote: > > > On Thu, Aug 30, 2018 at 06:19:52PM +0200, Michal Hocko wrote: > > >> On Thu 30-08-18 10:08:25, Jerome Glisse wrote: > > >>> On Thu,

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-30 Thread Jerome Glisse
On Thu, Aug 30, 2018 at 11:05:16AM -0700, Mike Kravetz wrote: > On 08/30/2018 09:57 AM, Jerome Glisse wrote: > > On Thu, Aug 30, 2018 at 06:19:52PM +0200, Michal Hocko wrote: > >> On Thu 30-08-18 10:08:25, Jerome Glisse wrote: > >>> On Thu, Aug 30, 2018 at 12:56:16PM +0200, Michal Hocko wrote: >

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-30 Thread Jerome Glisse
On Thu, Aug 30, 2018 at 11:05:16AM -0700, Mike Kravetz wrote: > On 08/30/2018 09:57 AM, Jerome Glisse wrote: > > On Thu, Aug 30, 2018 at 06:19:52PM +0200, Michal Hocko wrote: > >> On Thu 30-08-18 10:08:25, Jerome Glisse wrote: > >>> On Thu, Aug 30, 2018 at 12:56:16PM +0200, Michal Hocko wrote: >

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-30 Thread Mike Kravetz
On 08/30/2018 09:57 AM, Jerome Glisse wrote: > On Thu, Aug 30, 2018 at 06:19:52PM +0200, Michal Hocko wrote: >> On Thu 30-08-18 10:08:25, Jerome Glisse wrote: >>> On Thu, Aug 30, 2018 at 12:56:16PM +0200, Michal Hocko wrote: On Wed 29-08-18 17:11:07, Jerome Glisse wrote: > On Wed, Aug 29,

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-30 Thread Mike Kravetz
On 08/30/2018 09:57 AM, Jerome Glisse wrote: > On Thu, Aug 30, 2018 at 06:19:52PM +0200, Michal Hocko wrote: >> On Thu 30-08-18 10:08:25, Jerome Glisse wrote: >>> On Thu, Aug 30, 2018 at 12:56:16PM +0200, Michal Hocko wrote: On Wed 29-08-18 17:11:07, Jerome Glisse wrote: > On Wed, Aug 29,

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-30 Thread Jerome Glisse
On Thu, Aug 30, 2018 at 06:19:52PM +0200, Michal Hocko wrote: > On Thu 30-08-18 10:08:25, Jerome Glisse wrote: > > On Thu, Aug 30, 2018 at 12:56:16PM +0200, Michal Hocko wrote: > > > On Wed 29-08-18 17:11:07, Jerome Glisse wrote: > > > > On Wed, Aug 29, 2018 at 08:39:06PM +0200, Michal Hocko

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-30 Thread Jerome Glisse
On Thu, Aug 30, 2018 at 06:19:52PM +0200, Michal Hocko wrote: > On Thu 30-08-18 10:08:25, Jerome Glisse wrote: > > On Thu, Aug 30, 2018 at 12:56:16PM +0200, Michal Hocko wrote: > > > On Wed 29-08-18 17:11:07, Jerome Glisse wrote: > > > > On Wed, Aug 29, 2018 at 08:39:06PM +0200, Michal Hocko

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-30 Thread Michal Hocko
On Thu 30-08-18 10:08:25, Jerome Glisse wrote: > On Thu, Aug 30, 2018 at 12:56:16PM +0200, Michal Hocko wrote: > > On Wed 29-08-18 17:11:07, Jerome Glisse wrote: > > > On Wed, Aug 29, 2018 at 08:39:06PM +0200, Michal Hocko wrote: > > > > On Wed 29-08-18 14:14:25, Jerome Glisse wrote: > > > > > On

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-30 Thread Michal Hocko
On Thu 30-08-18 10:08:25, Jerome Glisse wrote: > On Thu, Aug 30, 2018 at 12:56:16PM +0200, Michal Hocko wrote: > > On Wed 29-08-18 17:11:07, Jerome Glisse wrote: > > > On Wed, Aug 29, 2018 at 08:39:06PM +0200, Michal Hocko wrote: > > > > On Wed 29-08-18 14:14:25, Jerome Glisse wrote: > > > > > On

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-30 Thread Jerome Glisse
On Thu, Aug 30, 2018 at 12:56:16PM +0200, Michal Hocko wrote: > On Wed 29-08-18 17:11:07, Jerome Glisse wrote: > > On Wed, Aug 29, 2018 at 08:39:06PM +0200, Michal Hocko wrote: > > > On Wed 29-08-18 14:14:25, Jerome Glisse wrote: > > > > On Wed, Aug 29, 2018 at 10:24:44AM -0700, Mike Kravetz

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-30 Thread Jerome Glisse
On Thu, Aug 30, 2018 at 12:56:16PM +0200, Michal Hocko wrote: > On Wed 29-08-18 17:11:07, Jerome Glisse wrote: > > On Wed, Aug 29, 2018 at 08:39:06PM +0200, Michal Hocko wrote: > > > On Wed 29-08-18 14:14:25, Jerome Glisse wrote: > > > > On Wed, Aug 29, 2018 at 10:24:44AM -0700, Mike Kravetz

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-30 Thread Michal Hocko
On Wed 29-08-18 17:11:07, Jerome Glisse wrote: > On Wed, Aug 29, 2018 at 08:39:06PM +0200, Michal Hocko wrote: > > On Wed 29-08-18 14:14:25, Jerome Glisse wrote: > > > On Wed, Aug 29, 2018 at 10:24:44AM -0700, Mike Kravetz wrote: > > [...] > > > > What would be the best mmu notifier interface to

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-30 Thread Michal Hocko
On Wed 29-08-18 17:11:07, Jerome Glisse wrote: > On Wed, Aug 29, 2018 at 08:39:06PM +0200, Michal Hocko wrote: > > On Wed 29-08-18 14:14:25, Jerome Glisse wrote: > > > On Wed, Aug 29, 2018 at 10:24:44AM -0700, Mike Kravetz wrote: > > [...] > > > > What would be the best mmu notifier interface to

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-29 Thread Mike Kravetz
On 08/29/2018 02:11 PM, Jerome Glisse wrote: > On Wed, Aug 29, 2018 at 08:39:06PM +0200, Michal Hocko wrote: >> On Wed 29-08-18 14:14:25, Jerome Glisse wrote: >>> On Wed, Aug 29, 2018 at 10:24:44AM -0700, Mike Kravetz wrote: >> [...] What would be the best mmu notifier interface to use where

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-29 Thread Mike Kravetz
On 08/29/2018 02:11 PM, Jerome Glisse wrote: > On Wed, Aug 29, 2018 at 08:39:06PM +0200, Michal Hocko wrote: >> On Wed 29-08-18 14:14:25, Jerome Glisse wrote: >>> On Wed, Aug 29, 2018 at 10:24:44AM -0700, Mike Kravetz wrote: >> [...] What would be the best mmu notifier interface to use where

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-29 Thread Jerome Glisse
On Wed, Aug 29, 2018 at 08:39:06PM +0200, Michal Hocko wrote: > On Wed 29-08-18 14:14:25, Jerome Glisse wrote: > > On Wed, Aug 29, 2018 at 10:24:44AM -0700, Mike Kravetz wrote: > [...] > > > What would be the best mmu notifier interface to use where there are no > > > start/end calls? > > > Or, is

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-29 Thread Jerome Glisse
On Wed, Aug 29, 2018 at 08:39:06PM +0200, Michal Hocko wrote: > On Wed 29-08-18 14:14:25, Jerome Glisse wrote: > > On Wed, Aug 29, 2018 at 10:24:44AM -0700, Mike Kravetz wrote: > [...] > > > What would be the best mmu notifier interface to use where there are no > > > start/end calls? > > > Or, is

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-29 Thread Michal Hocko
On Wed 29-08-18 14:14:25, Jerome Glisse wrote: > On Wed, Aug 29, 2018 at 10:24:44AM -0700, Mike Kravetz wrote: [...] > > What would be the best mmu notifier interface to use where there are no > > start/end calls? > > Or, is the best solution to add the start/end calls as is done in later > >

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-29 Thread Michal Hocko
On Wed 29-08-18 14:14:25, Jerome Glisse wrote: > On Wed, Aug 29, 2018 at 10:24:44AM -0700, Mike Kravetz wrote: [...] > > What would be the best mmu notifier interface to use where there are no > > start/end calls? > > Or, is the best solution to add the start/end calls as is done in later > >

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-29 Thread Jerome Glisse
On Wed, Aug 29, 2018 at 10:24:44AM -0700, Mike Kravetz wrote: > On 08/27/2018 06:46 AM, Jerome Glisse wrote: > > On Mon, Aug 27, 2018 at 09:46:45AM +0200, Michal Hocko wrote: > >> On Fri 24-08-18 11:08:24, Mike Kravetz wrote: > >>> Here is an updated patch which does as you suggest above. > >>

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-29 Thread Jerome Glisse
On Wed, Aug 29, 2018 at 10:24:44AM -0700, Mike Kravetz wrote: > On 08/27/2018 06:46 AM, Jerome Glisse wrote: > > On Mon, Aug 27, 2018 at 09:46:45AM +0200, Michal Hocko wrote: > >> On Fri 24-08-18 11:08:24, Mike Kravetz wrote: > >>> Here is an updated patch which does as you suggest above. > >>

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-29 Thread Mike Kravetz
On 08/27/2018 06:46 AM, Jerome Glisse wrote: > On Mon, Aug 27, 2018 at 09:46:45AM +0200, Michal Hocko wrote: >> On Fri 24-08-18 11:08:24, Mike Kravetz wrote: >>> Here is an updated patch which does as you suggest above. >> [...] >>> @@ -1409,6 +1419,32 @@ static bool try_to_unmap_one(struct page

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-29 Thread Mike Kravetz
On 08/27/2018 06:46 AM, Jerome Glisse wrote: > On Mon, Aug 27, 2018 at 09:46:45AM +0200, Michal Hocko wrote: >> On Fri 24-08-18 11:08:24, Mike Kravetz wrote: >>> Here is an updated patch which does as you suggest above. >> [...] >>> @@ -1409,6 +1419,32 @@ static bool try_to_unmap_one(struct page

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-27 Thread Michal Hocko
On Fri 24-08-18 11:08:24, Mike Kravetz wrote: [...] > From: Mike Kravetz > Date: Fri, 24 Aug 2018 10:58:20 -0700 > Subject: [PATCH v7 1/2] mm: migration: fix migration of huge PMD shared pages > > The page migration code employs try_to_unmap() to try and unmap the > source page. This is

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-27 Thread Michal Hocko
On Fri 24-08-18 11:08:24, Mike Kravetz wrote: [...] > From: Mike Kravetz > Date: Fri, 24 Aug 2018 10:58:20 -0700 > Subject: [PATCH v7 1/2] mm: migration: fix migration of huge PMD shared pages > > The page migration code employs try_to_unmap() to try and unmap the > source page. This is

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-27 Thread Michal Hocko
On Mon 27-08-18 09:46:33, Jerome Glisse wrote: > On Mon, Aug 27, 2018 at 09:46:45AM +0200, Michal Hocko wrote: > > On Fri 24-08-18 11:08:24, Mike Kravetz wrote: > > > On 08/24/2018 01:41 AM, Michal Hocko wrote: > > > > On Thu 23-08-18 13:59:16, Mike Kravetz wrote: > > > > > > > > Acked-by: Michal

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-27 Thread Michal Hocko
On Mon 27-08-18 09:46:33, Jerome Glisse wrote: > On Mon, Aug 27, 2018 at 09:46:45AM +0200, Michal Hocko wrote: > > On Fri 24-08-18 11:08:24, Mike Kravetz wrote: > > > On 08/24/2018 01:41 AM, Michal Hocko wrote: > > > > On Thu 23-08-18 13:59:16, Mike Kravetz wrote: > > > > > > > > Acked-by: Michal

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-27 Thread Mike Kravetz
On 08/27/2018 12:46 AM, Michal Hocko wrote: > On Fri 24-08-18 11:08:24, Mike Kravetz wrote: >> On 08/24/2018 01:41 AM, Michal Hocko wrote: >>> On Thu 23-08-18 13:59:16, Mike Kravetz wrote: >>> >>> Acked-by: Michal Hocko >>> >>> One nit below. >>> >>> [...] diff --git a/mm/hugetlb.c

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-27 Thread Mike Kravetz
On 08/27/2018 12:46 AM, Michal Hocko wrote: > On Fri 24-08-18 11:08:24, Mike Kravetz wrote: >> On 08/24/2018 01:41 AM, Michal Hocko wrote: >>> On Thu 23-08-18 13:59:16, Mike Kravetz wrote: >>> >>> Acked-by: Michal Hocko >>> >>> One nit below. >>> >>> [...] diff --git a/mm/hugetlb.c

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-27 Thread Jerome Glisse
On Mon, Aug 27, 2018 at 09:46:45AM +0200, Michal Hocko wrote: > On Fri 24-08-18 11:08:24, Mike Kravetz wrote: > > On 08/24/2018 01:41 AM, Michal Hocko wrote: > > > On Thu 23-08-18 13:59:16, Mike Kravetz wrote: > > > > > > Acked-by: Michal Hocko > > > > > > One nit below. > > > > > > [...] > >

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-27 Thread Jerome Glisse
On Mon, Aug 27, 2018 at 09:46:45AM +0200, Michal Hocko wrote: > On Fri 24-08-18 11:08:24, Mike Kravetz wrote: > > On 08/24/2018 01:41 AM, Michal Hocko wrote: > > > On Thu 23-08-18 13:59:16, Mike Kravetz wrote: > > > > > > Acked-by: Michal Hocko > > > > > > One nit below. > > > > > > [...] > >

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-27 Thread Michal Hocko
On Fri 24-08-18 11:08:24, Mike Kravetz wrote: > On 08/24/2018 01:41 AM, Michal Hocko wrote: > > On Thu 23-08-18 13:59:16, Mike Kravetz wrote: > > > > Acked-by: Michal Hocko > > > > One nit below. > > > > [...] > >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c > >> index 3103099f64fd..a73c5728e961

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-27 Thread Michal Hocko
On Fri 24-08-18 11:08:24, Mike Kravetz wrote: > On 08/24/2018 01:41 AM, Michal Hocko wrote: > > On Thu 23-08-18 13:59:16, Mike Kravetz wrote: > > > > Acked-by: Michal Hocko > > > > One nit below. > > > > [...] > >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c > >> index 3103099f64fd..a73c5728e961

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-24 Thread Mike Kravetz
On 08/24/2018 01:41 AM, Michal Hocko wrote: > On Thu 23-08-18 13:59:16, Mike Kravetz wrote: > > Acked-by: Michal Hocko > > One nit below. > > [...] >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >> index 3103099f64fd..a73c5728e961 100644 >> --- a/mm/hugetlb.c >> +++ b/mm/hugetlb.c >> @@ -4548,6

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-24 Thread Mike Kravetz
On 08/24/2018 01:41 AM, Michal Hocko wrote: > On Thu 23-08-18 13:59:16, Mike Kravetz wrote: > > Acked-by: Michal Hocko > > One nit below. > > [...] >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >> index 3103099f64fd..a73c5728e961 100644 >> --- a/mm/hugetlb.c >> +++ b/mm/hugetlb.c >> @@ -4548,6

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-24 Thread Michal Hocko
On Thu 23-08-18 13:59:16, Mike Kravetz wrote: [...] > @@ -1409,6 +1419,32 @@ static bool try_to_unmap_one(struct page *page, struct > vm_area_struct *vma, > subpage = page - page_to_pfn(page) + pte_pfn(*pvmw.pte); > address = pvmw.address; > > + if

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-24 Thread Michal Hocko
On Thu 23-08-18 13:59:16, Mike Kravetz wrote: [...] > @@ -1409,6 +1419,32 @@ static bool try_to_unmap_one(struct page *page, struct > vm_area_struct *vma, > subpage = page - page_to_pfn(page) + pte_pfn(*pvmw.pte); > address = pvmw.address; > > + if

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-24 Thread Michal Hocko
On Thu 23-08-18 13:59:16, Mike Kravetz wrote: > The page migration code employs try_to_unmap() to try and unmap the > source page. This is accomplished by using rmap_walk to find all > vmas where the page is mapped. This search stops when page mapcount > is zero. For shared PMD huge pages, the

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-24 Thread Michal Hocko
On Thu 23-08-18 13:59:16, Mike Kravetz wrote: > The page migration code employs try_to_unmap() to try and unmap the > source page. This is accomplished by using rmap_walk to find all > vmas where the page is mapped. This search stops when page mapcount > is zero. For shared PMD huge pages, the

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-23 Thread Naoya Horiguchi
On Thu, Aug 23, 2018 at 01:59:16PM -0700, Mike Kravetz wrote: > The page migration code employs try_to_unmap() to try and unmap the > source page. This is accomplished by using rmap_walk to find all > vmas where the page is mapped. This search stops when page mapcount > is zero. For shared PMD

Re: [PATCH v6 1/2] mm: migration: fix migration of huge PMD shared pages

2018-08-23 Thread Naoya Horiguchi
On Thu, Aug 23, 2018 at 01:59:16PM -0700, Mike Kravetz wrote: > The page migration code employs try_to_unmap() to try and unmap the > source page. This is accomplished by using rmap_walk to find all > vmas where the page is mapped. This search stops when page mapcount > is zero. For shared PMD