Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-07 Thread Johannes Weiner 
On Tue, Mar 07, 2017 at 02:55:51PM +0900, Minchan Kim wrote:
> From d42d296950c3bbce74afddcff307fa18eef305fe Mon Sep 17 00:00:00 2001
> From: Minchan Kim 
> Date: Tue, 7 Mar 2017 14:48:37 +0900
> Subject: [PATCH] mm: fix lazyfree bug on check in try_to_unmap_one
> 
> If a page is swapbacked, it means it should be in swapcache
> in try_to_unmap_one's path.
> 
> If a page is !swapbacked, it mean it shouldn't be in swapcache
> in try_to_unmap_one's path.
> 
> Check both two cases all at once and if it fails, warn and
> return SWAP_FAIL. Such bug never mean we should shut down
> the kernel.
> 
> Suggested-by: Johannes Weiner 
> Signed-off-by: Minchan Kim 

Acked-by: Johannes Weiner 

Thanks Minchan

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-07 Thread Johannes Weiner 
On Tue, Mar 07, 2017 at 02:55:51PM +0900, Minchan Kim wrote:
> From d42d296950c3bbce74afddcff307fa18eef305fe Mon Sep 17 00:00:00 2001
> From: Minchan Kim 
> Date: Tue, 7 Mar 2017 14:48:37 +0900
> Subject: [PATCH] mm: fix lazyfree bug on check in try_to_unmap_one
> 
> If a page is swapbacked, it means it should be in swapcache
> in try_to_unmap_one's path.
> 
> If a page is !swapbacked, it mean it shouldn't be in swapcache
> in try_to_unmap_one's path.
> 
> Check both two cases all at once and if it fails, warn and
> return SWAP_FAIL. Such bug never mean we should shut down
> the kernel.
> 
> Suggested-by: Johannes Weiner 
> Signed-off-by: Minchan Kim 

Acked-by: Johannes Weiner 

Thanks Minchan

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-07 Thread Michal Hocko 
On Tue 07-03-17 14:55:51, Minchan Kim wrote:
[...]
> >From d42d296950c3bbce74afddcff307fa18eef305fe Mon Sep 17 00:00:00 2001
> From: Minchan Kim 
> Date: Tue, 7 Mar 2017 14:48:37 +0900
> Subject: [PATCH] mm: fix lazyfree bug on check in try_to_unmap_one
> 
> If a page is swapbacked, it means it should be in swapcache
> in try_to_unmap_one's path.
> 
> If a page is !swapbacked, it mean it shouldn't be in swapcache
> in try_to_unmap_one's path.
> 
> Check both two cases all at once and if it fails, warn and
> return SWAP_FAIL. Such bug never mean we should shut down
> the kernel.
> 
> Suggested-by: Johannes Weiner 
> Signed-off-by: Minchan Kim 

looks good to me
Acked-by: Michal Hocko 

> ---
>  mm/rmap.c | 9 +++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 35acb83..9925f32 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1413,8 +1413,13 @@ static int try_to_unmap_one(struct page *page, struct 
> vm_area_struct *vma,
>* Store the swap location in the pte.
>* See handle_pte_fault() ...
>*/
> - VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> PageSwapBacked(page),
> - page);
> + if (VM_WARN_ON_ONCE(PageSwapBacked(page) !=
> + PageSwapCache(page))) {
> + ret = SWAP_FAIL;
> + page_vma_mapped_walk_done();
> + break;
> +
> + }
>  
>   /* MADV_FREE page check */
>   if (!PageSwapBacked(page)) {
> -- 
> 2.7.4
> 

-- 
Michal Hocko
SUSE Labs

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-07 Thread Michal Hocko 
On Tue 07-03-17 14:55:51, Minchan Kim wrote:
[...]
> >From d42d296950c3bbce74afddcff307fa18eef305fe Mon Sep 17 00:00:00 2001
> From: Minchan Kim 
> Date: Tue, 7 Mar 2017 14:48:37 +0900
> Subject: [PATCH] mm: fix lazyfree bug on check in try_to_unmap_one
> 
> If a page is swapbacked, it means it should be in swapcache
> in try_to_unmap_one's path.
> 
> If a page is !swapbacked, it mean it shouldn't be in swapcache
> in try_to_unmap_one's path.
> 
> Check both two cases all at once and if it fails, warn and
> return SWAP_FAIL. Such bug never mean we should shut down
> the kernel.
> 
> Suggested-by: Johannes Weiner 
> Signed-off-by: Minchan Kim 

looks good to me
Acked-by: Michal Hocko 

> ---
>  mm/rmap.c | 9 +++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 35acb83..9925f32 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1413,8 +1413,13 @@ static int try_to_unmap_one(struct page *page, struct 
> vm_area_struct *vma,
>* Store the swap location in the pte.
>* See handle_pte_fault() ...
>*/
> - VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> PageSwapBacked(page),
> - page);
> + if (VM_WARN_ON_ONCE(PageSwapBacked(page) !=
> + PageSwapCache(page))) {
> + ret = SWAP_FAIL;
> + page_vma_mapped_walk_done();
> + break;
> +
> + }
>  
>   /* MADV_FREE page check */
>   if (!PageSwapBacked(page)) {
> -- 
> 2.7.4
> 

-- 
Michal Hocko
SUSE Labs

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-06 Thread Minchan Kim 
On Mon, Mar 06, 2017 at 10:49:06AM -0500, Johannes Weiner wrote:

< snip >

> > @@ -1413,20 +1413,24 @@ static int try_to_unmap_one(struct page *page, 
> > struct vm_area_struct *vma,
> >  * Store the swap location in the pte.
> >  * See handle_pte_fault() ...
> >  */
> > -   VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> > PageSwapBacked(page),
> > -   page);
> > +   if (VM_WARN_ON_ONCE(PageSwapBacked(page) &&
> > +   !PageSwapCache(page))) {
> > +   ret = SWAP_FAIL;
> 
> But you're not adding the !swapbacked && swapcache case?
> 
> > +   page_vma_mapped_walk_done();
> > +   break;
> > +   }
> 
> [...]
> 
> > -   /*
> > -* swapin page could be clean, it has data stored in
> > -* swap. We can't silently discard it without setting
> > -* swap entry in the page table.
> > -*/
> > -   if (!PageDirty(page) && !PageSwapCache(page)) {
> > -   /* It's a freeable page by MADV_FREE */
> > -   dec_mm_counter(mm, MM_ANONPAGES);
> > -   goto discard;
> > -   } else if (!PageSwapBacked(page)) {
> > -   /* dirty MADV_FREE page */
> > +   /* MADV_FREE page check */
> > +   if (!PageSwapBacked(page)) {
> > +   if (!PageDirty(page)) {
> > +   dec_mm_counter(mm, MM_ANONPAGES);
> > +   goto discard;
> > +   }
> 
> Andrew already has this, you might want to send the warning changes as
> a separate patch on top of this one.

Here it goes.

>From d42d296950c3bbce74afddcff307fa18eef305fe Mon Sep 17 00:00:00 2001
From: Minchan Kim 
Date: Tue, 7 Mar 2017 14:48:37 +0900
Subject: [PATCH] mm: fix lazyfree bug on check in try_to_unmap_one

If a page is swapbacked, it means it should be in swapcache
in try_to_unmap_one's path.

If a page is !swapbacked, it mean it shouldn't be in swapcache
in try_to_unmap_one's path.

Check both two cases all at once and if it fails, warn and
return SWAP_FAIL. Such bug never mean we should shut down
the kernel.

Suggested-by: Johannes Weiner 
Signed-off-by: Minchan Kim 
---
 mm/rmap.c | 9 +++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index 35acb83..9925f32 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1413,8 +1413,13 @@ static int try_to_unmap_one(struct page *page, struct 
vm_area_struct *vma,
 * Store the swap location in the pte.
 * See handle_pte_fault() ...
 */
-   VM_BUG_ON_PAGE(!PageSwapCache(page) && 
PageSwapBacked(page),
-   page);
+   if (VM_WARN_ON_ONCE(PageSwapBacked(page) !=
+   PageSwapCache(page))) {
+   ret = SWAP_FAIL;
+   page_vma_mapped_walk_done();
+   break;
+
+   }
 
/* MADV_FREE page check */
if (!PageSwapBacked(page)) {
-- 
2.7.4

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-06 Thread Minchan Kim 
On Mon, Mar 06, 2017 at 10:49:06AM -0500, Johannes Weiner wrote:

< snip >

> > @@ -1413,20 +1413,24 @@ static int try_to_unmap_one(struct page *page, 
> > struct vm_area_struct *vma,
> >  * Store the swap location in the pte.
> >  * See handle_pte_fault() ...
> >  */
> > -   VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> > PageSwapBacked(page),
> > -   page);
> > +   if (VM_WARN_ON_ONCE(PageSwapBacked(page) &&
> > +   !PageSwapCache(page))) {
> > +   ret = SWAP_FAIL;
> 
> But you're not adding the !swapbacked && swapcache case?
> 
> > +   page_vma_mapped_walk_done();
> > +   break;
> > +   }
> 
> [...]
> 
> > -   /*
> > -* swapin page could be clean, it has data stored in
> > -* swap. We can't silently discard it without setting
> > -* swap entry in the page table.
> > -*/
> > -   if (!PageDirty(page) && !PageSwapCache(page)) {
> > -   /* It's a freeable page by MADV_FREE */
> > -   dec_mm_counter(mm, MM_ANONPAGES);
> > -   goto discard;
> > -   } else if (!PageSwapBacked(page)) {
> > -   /* dirty MADV_FREE page */
> > +   /* MADV_FREE page check */
> > +   if (!PageSwapBacked(page)) {
> > +   if (!PageDirty(page)) {
> > +   dec_mm_counter(mm, MM_ANONPAGES);
> > +   goto discard;
> > +   }
> 
> Andrew already has this, you might want to send the warning changes as
> a separate patch on top of this one.

Here it goes.

>From d42d296950c3bbce74afddcff307fa18eef305fe Mon Sep 17 00:00:00 2001
From: Minchan Kim 
Date: Tue, 7 Mar 2017 14:48:37 +0900
Subject: [PATCH] mm: fix lazyfree bug on check in try_to_unmap_one

If a page is swapbacked, it means it should be in swapcache
in try_to_unmap_one's path.

If a page is !swapbacked, it mean it shouldn't be in swapcache
in try_to_unmap_one's path.

Check both two cases all at once and if it fails, warn and
return SWAP_FAIL. Such bug never mean we should shut down
the kernel.

Suggested-by: Johannes Weiner 
Signed-off-by: Minchan Kim 
---
 mm/rmap.c | 9 +++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index 35acb83..9925f32 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1413,8 +1413,13 @@ static int try_to_unmap_one(struct page *page, struct 
vm_area_struct *vma,
 * Store the swap location in the pte.
 * See handle_pte_fault() ...
 */
-   VM_BUG_ON_PAGE(!PageSwapCache(page) && 
PageSwapBacked(page),
-   page);
+   if (VM_WARN_ON_ONCE(PageSwapBacked(page) !=
+   PageSwapCache(page))) {
+   ret = SWAP_FAIL;
+   page_vma_mapped_walk_done();
+   break;
+
+   }
 
/* MADV_FREE page check */
if (!PageSwapBacked(page)) {
-- 
2.7.4

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-06 Thread Minchan Kim 
On Mon, Mar 06, 2017 at 10:49:06AM -0500, Johannes Weiner wrote:
> On Mon, Mar 06, 2017 at 12:03:44PM +0900, Minchan Kim wrote:
> > On Fri, Mar 03, 2017 at 10:18:51AM -0500, Johannes Weiner wrote:
> > > On Fri, Mar 03, 2017 at 11:52:37AM +0900, Minchan Kim wrote:
> > > > On Tue, Feb 28, 2017 at 04:32:38PM -0800, a...@linux-foundation.org 
> > > > wrote:
> > > > > 
> > > > > The patch titled
> > > > >  Subject: mm: reclaim MADV_FREE pages
> > > > > has been added to the -mm tree.  Its filename is
> > > > >  mm-reclaim-madv_free-pages.patch
> > > > > 
> > > > > This patch should soon appear at
> > > > > 
> > > > > http://ozlabs.org/~akpm/mmots/broken-out/mm-reclaim-madv_free-pages.patch
> > > > > and later at
> > > > > 
> > > > > http://ozlabs.org/~akpm/mmotm/broken-out/mm-reclaim-madv_free-pages.patch
> > > > > 
> > > > > Before you just go and hit "reply", please:
> > > > >a) Consider who else should be cc'ed
> > > > >b) Prefer to cc a suitable mailing list as well
> > > > >c) Ideally: find the original patch on the mailing list and do a
> > > > >   reply-to-all to that, adding suitable additional cc's
> > > > > 
> > > > > *** Remember to use Documentation/SubmitChecklist when testing your 
> > > > > code ***
> > > > > 
> > > > > The -mm tree is included into linux-next and is updated
> > > > > there every 3-4 working days
> > > > > 
> > > > > --
> > > > > From: Shaohua Li 
> > > > > Subject: mm: reclaim MADV_FREE pages
> > > > > 
> > > > > When memory pressure is high, we free MADV_FREE pages.  If the pages 
> > > > > are
> > > > > not dirty in pte, the pages could be freed immediately.  Otherwise we
> > > > > can't reclaim them.  We put the pages back to anonumous LRU list (by
> > > > > setting SwapBacked flag) and the pages will be reclaimed in normal 
> > > > > swapout
> > > > > way.
> > > > > 
> > > > > We use normal page reclaim policy.  Since MADV_FREE pages are put into
> > > > > inactive file list, such pages and inactive file pages are reclaimed
> > > > > according to their age.  This is expected, because we don't want to
> > > > > reclaim too many MADV_FREE pages before used once pages.
> > > > > 
> > > > > Based on Minchan's original patch
> > > > > 
> > > > > Link: 
> > > > > http://lkml.kernel.org/r/14b8eb1d3f6bf6cc492833f183ac8c304e560484.1487965799.git.s...@fb.com
> > > > > Signed-off-by: Shaohua Li 
> > > > > Acked-by: Minchan Kim 
> > > > > Acked-by: Michal Hocko 
> > > > > Acked-by: Johannes Weiner 
> > > > > Acked-by: Hillf Danton 
> > > > > Cc: Hugh Dickins 
> > > > > Cc: Rik van Riel 
> > > > > Cc: Mel Gorman 
> > > > > Signed-off-by: Andrew Morton 
> > > > > ---
> > > > 
> > > > < snip >
> > > > 
> > > > > @@ -1419,11 +1413,21 @@ static int try_to_unmap_one(struct page
> > > > >   VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> > > > > PageSwapBacked(page),
> > > > >   page);
> > > > >  
> > > > > - if (!PageDirty(page)) {
> > > > > + /*
> > > > > +  * swapin page could be clean, it has data 
> > > > > stored in
> > > > > +  * swap. We can't silently discard it without 
> > > > > setting
> > > > > +  * swap entry in the page table.
> > > > > +  */
> > > > > + if (!PageDirty(page) && !PageSwapCache(page)) {
> > > > >   /* It's a freeable page by MADV_FREE */
> > > > >   dec_mm_counter(mm, MM_ANONPAGES);
> > > > > - rp->lazyfreed++;
> > > > >   goto discard;
> > > > > + } else if (!PageSwapBacked(page)) {
> > > > > + /* dirty MADV_FREE page */
> > > > > + set_pte_at(mm, address, pvmw.pte, 
> > > > > pteval);
> > > > > + ret = SWAP_DIRTY;
> > > > > + page_vma_mapped_walk_done();
> > > > > + break;
> > > > >   }
> > > > 
> > > > There is no point to make this logic complicated with clean swapin-page.
> > > > 
> > > > Andrew,
> > > > Could you fold below patch into the mm-reclaim-madv_free-pages.patch
> > > > if others are not against?
> > > > 
> > > > Thanks.
> > > > 
> > > > From 0c28f6560fbc4e65da4f4a8cc4664ab9f7b11cf3 Mon Sep 17 00:00:00 2001
> > > > From: Minchan Kim 
> > > > Date: Fri, 3 Mar 2017 11:42:52 +0900
> > > > Subject: [PATCH] mm: clean up lazyfree page handling
> > > > 
> > > > We can make it simple to understand without need to be aware of
> > > > clean-swapin page.
> > > > This patch just clean up lazyfree

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-06 Thread Minchan Kim 
On Mon, Mar 06, 2017 at 10:49:06AM -0500, Johannes Weiner wrote:
> On Mon, Mar 06, 2017 at 12:03:44PM +0900, Minchan Kim wrote:
> > On Fri, Mar 03, 2017 at 10:18:51AM -0500, Johannes Weiner wrote:
> > > On Fri, Mar 03, 2017 at 11:52:37AM +0900, Minchan Kim wrote:
> > > > On Tue, Feb 28, 2017 at 04:32:38PM -0800, a...@linux-foundation.org 
> > > > wrote:
> > > > > 
> > > > > The patch titled
> > > > >  Subject: mm: reclaim MADV_FREE pages
> > > > > has been added to the -mm tree.  Its filename is
> > > > >  mm-reclaim-madv_free-pages.patch
> > > > > 
> > > > > This patch should soon appear at
> > > > > 
> > > > > http://ozlabs.org/~akpm/mmots/broken-out/mm-reclaim-madv_free-pages.patch
> > > > > and later at
> > > > > 
> > > > > http://ozlabs.org/~akpm/mmotm/broken-out/mm-reclaim-madv_free-pages.patch
> > > > > 
> > > > > Before you just go and hit "reply", please:
> > > > >a) Consider who else should be cc'ed
> > > > >b) Prefer to cc a suitable mailing list as well
> > > > >c) Ideally: find the original patch on the mailing list and do a
> > > > >   reply-to-all to that, adding suitable additional cc's
> > > > > 
> > > > > *** Remember to use Documentation/SubmitChecklist when testing your 
> > > > > code ***
> > > > > 
> > > > > The -mm tree is included into linux-next and is updated
> > > > > there every 3-4 working days
> > > > > 
> > > > > --
> > > > > From: Shaohua Li 
> > > > > Subject: mm: reclaim MADV_FREE pages
> > > > > 
> > > > > When memory pressure is high, we free MADV_FREE pages.  If the pages 
> > > > > are
> > > > > not dirty in pte, the pages could be freed immediately.  Otherwise we
> > > > > can't reclaim them.  We put the pages back to anonumous LRU list (by
> > > > > setting SwapBacked flag) and the pages will be reclaimed in normal 
> > > > > swapout
> > > > > way.
> > > > > 
> > > > > We use normal page reclaim policy.  Since MADV_FREE pages are put into
> > > > > inactive file list, such pages and inactive file pages are reclaimed
> > > > > according to their age.  This is expected, because we don't want to
> > > > > reclaim too many MADV_FREE pages before used once pages.
> > > > > 
> > > > > Based on Minchan's original patch
> > > > > 
> > > > > Link: 
> > > > > http://lkml.kernel.org/r/14b8eb1d3f6bf6cc492833f183ac8c304e560484.1487965799.git.s...@fb.com
> > > > > Signed-off-by: Shaohua Li 
> > > > > Acked-by: Minchan Kim 
> > > > > Acked-by: Michal Hocko 
> > > > > Acked-by: Johannes Weiner 
> > > > > Acked-by: Hillf Danton 
> > > > > Cc: Hugh Dickins 
> > > > > Cc: Rik van Riel 
> > > > > Cc: Mel Gorman 
> > > > > Signed-off-by: Andrew Morton 
> > > > > ---
> > > > 
> > > > < snip >
> > > > 
> > > > > @@ -1419,11 +1413,21 @@ static int try_to_unmap_one(struct page
> > > > >   VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> > > > > PageSwapBacked(page),
> > > > >   page);
> > > > >  
> > > > > - if (!PageDirty(page)) {
> > > > > + /*
> > > > > +  * swapin page could be clean, it has data 
> > > > > stored in
> > > > > +  * swap. We can't silently discard it without 
> > > > > setting
> > > > > +  * swap entry in the page table.
> > > > > +  */
> > > > > + if (!PageDirty(page) && !PageSwapCache(page)) {
> > > > >   /* It's a freeable page by MADV_FREE */
> > > > >   dec_mm_counter(mm, MM_ANONPAGES);
> > > > > - rp->lazyfreed++;
> > > > >   goto discard;
> > > > > + } else if (!PageSwapBacked(page)) {
> > > > > + /* dirty MADV_FREE page */
> > > > > + set_pte_at(mm, address, pvmw.pte, 
> > > > > pteval);
> > > > > + ret = SWAP_DIRTY;
> > > > > + page_vma_mapped_walk_done();
> > > > > + break;
> > > > >   }
> > > > 
> > > > There is no point to make this logic complicated with clean swapin-page.
> > > > 
> > > > Andrew,
> > > > Could you fold below patch into the mm-reclaim-madv_free-pages.patch
> > > > if others are not against?
> > > > 
> > > > Thanks.
> > > > 
> > > > From 0c28f6560fbc4e65da4f4a8cc4664ab9f7b11cf3 Mon Sep 17 00:00:00 2001
> > > > From: Minchan Kim 
> > > > Date: Fri, 3 Mar 2017 11:42:52 +0900
> > > > Subject: [PATCH] mm: clean up lazyfree page handling
> > > > 
> > > > We can make it simple to understand without need to be aware of
> > > > clean-swapin page.
> > > > This patch just clean up lazyfree page handling in try_to_unmap_one.
> > > > 
> > > > Signed-off-by: Minchan Kim 
> > > 
> > > Agreed, this is a litle easier to follow.
> > > 
> > > Acked-by: Johannes Weiner 
> > 
> > Thanks, Johannes.
> > 
> > > 
> > >

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-06 Thread Johannes Weiner 
On Mon, Mar 06, 2017 at 12:03:44PM +0900, Minchan Kim wrote:
> On Fri, Mar 03, 2017 at 10:18:51AM -0500, Johannes Weiner wrote:
> > On Fri, Mar 03, 2017 at 11:52:37AM +0900, Minchan Kim wrote:
> > > On Tue, Feb 28, 2017 at 04:32:38PM -0800, a...@linux-foundation.org wrote:
> > > > 
> > > > The patch titled
> > > >  Subject: mm: reclaim MADV_FREE pages
> > > > has been added to the -mm tree.  Its filename is
> > > >  mm-reclaim-madv_free-pages.patch
> > > > 
> > > > This patch should soon appear at
> > > > 
> > > > http://ozlabs.org/~akpm/mmots/broken-out/mm-reclaim-madv_free-pages.patch
> > > > and later at
> > > > 
> > > > http://ozlabs.org/~akpm/mmotm/broken-out/mm-reclaim-madv_free-pages.patch
> > > > 
> > > > Before you just go and hit "reply", please:
> > > >a) Consider who else should be cc'ed
> > > >b) Prefer to cc a suitable mailing list as well
> > > >c) Ideally: find the original patch on the mailing list and do a
> > > >   reply-to-all to that, adding suitable additional cc's
> > > > 
> > > > *** Remember to use Documentation/SubmitChecklist when testing your 
> > > > code ***
> > > > 
> > > > The -mm tree is included into linux-next and is updated
> > > > there every 3-4 working days
> > > > 
> > > > --
> > > > From: Shaohua Li 
> > > > Subject: mm: reclaim MADV_FREE pages
> > > > 
> > > > When memory pressure is high, we free MADV_FREE pages.  If the pages are
> > > > not dirty in pte, the pages could be freed immediately.  Otherwise we
> > > > can't reclaim them.  We put the pages back to anonumous LRU list (by
> > > > setting SwapBacked flag) and the pages will be reclaimed in normal 
> > > > swapout
> > > > way.
> > > > 
> > > > We use normal page reclaim policy.  Since MADV_FREE pages are put into
> > > > inactive file list, such pages and inactive file pages are reclaimed
> > > > according to their age.  This is expected, because we don't want to
> > > > reclaim too many MADV_FREE pages before used once pages.
> > > > 
> > > > Based on Minchan's original patch
> > > > 
> > > > Link: 
> > > > http://lkml.kernel.org/r/14b8eb1d3f6bf6cc492833f183ac8c304e560484.1487965799.git.s...@fb.com
> > > > Signed-off-by: Shaohua Li 
> > > > Acked-by: Minchan Kim 
> > > > Acked-by: Michal Hocko 
> > > > Acked-by: Johannes Weiner 
> > > > Acked-by: Hillf Danton 
> > > > Cc: Hugh Dickins 
> > > > Cc: Rik van Riel 
> > > > Cc: Mel Gorman 
> > > > Signed-off-by: Andrew Morton 
> > > > ---
> > > 
> > > < snip >
> > > 
> > > > @@ -1419,11 +1413,21 @@ static int try_to_unmap_one(struct page
> > > > VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> > > > PageSwapBacked(page),
> > > > page);
> > > >  
> > > > -   if (!PageDirty(page)) {
> > > > +   /*
> > > > +* swapin page could be clean, it has data 
> > > > stored in
> > > > +* swap. We can't silently discard it without 
> > > > setting
> > > > +* swap entry in the page table.
> > > > +*/
> > > > +   if (!PageDirty(page) && !PageSwapCache(page)) {
> > > > /* It's a freeable page by MADV_FREE */
> > > > dec_mm_counter(mm, MM_ANONPAGES);
> > > > -   rp->lazyfreed++;
> > > > goto discard;
> > > > +   } else if (!PageSwapBacked(page)) {
> > > > +   /* dirty MADV_FREE page */
> > > > +   set_pte_at(mm, address, pvmw.pte, 
> > > > pteval);
> > > > +   ret = SWAP_DIRTY;
> > > > +   page_vma_mapped_walk_done();
> > > > +   break;
> > > > }
> > > 
> > > There is no point to make this logic complicated with clean swapin-page.
> > > 
> > > Andrew,
> > > Could you fold below patch into the mm-reclaim-madv_free-pages.patch
> > > if others are not against?
> > > 
> > > Thanks.
> > > 
> > > From 0c28f6560fbc4e65da4f4a8cc4664ab9f7b11cf3 Mon Sep 17 00:00:00 2001
> > > From: Minchan Kim 
> > > Date: Fri, 3 Mar 2017 11:42:52 +0900
> > > Subject: [PATCH] mm: clean up lazyfree page handling
> > > 
> > > We can make it simple to understand without need to be aware of
> > > clean-swapin page.
> > > This patch just clean up lazyfree page handling in try_to_unmap_one.
> > > 
> > > Signed-off-by: Minchan Kim 
> > 
> > Agreed, this is a litle easier to follow.
> > 
> > Acked-by: Johannes Weiner 
> 
> Thanks, Johannes.
> 
> > 
> > > ---
> > >

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-06 Thread Johannes Weiner 
On Mon, Mar 06, 2017 at 12:03:44PM +0900, Minchan Kim wrote:
> On Fri, Mar 03, 2017 at 10:18:51AM -0500, Johannes Weiner wrote:
> > On Fri, Mar 03, 2017 at 11:52:37AM +0900, Minchan Kim wrote:
> > > On Tue, Feb 28, 2017 at 04:32:38PM -0800, a...@linux-foundation.org wrote:
> > > > 
> > > > The patch titled
> > > >  Subject: mm: reclaim MADV_FREE pages
> > > > has been added to the -mm tree.  Its filename is
> > > >  mm-reclaim-madv_free-pages.patch
> > > > 
> > > > This patch should soon appear at
> > > > 
> > > > http://ozlabs.org/~akpm/mmots/broken-out/mm-reclaim-madv_free-pages.patch
> > > > and later at
> > > > 
> > > > http://ozlabs.org/~akpm/mmotm/broken-out/mm-reclaim-madv_free-pages.patch
> > > > 
> > > > Before you just go and hit "reply", please:
> > > >a) Consider who else should be cc'ed
> > > >b) Prefer to cc a suitable mailing list as well
> > > >c) Ideally: find the original patch on the mailing list and do a
> > > >   reply-to-all to that, adding suitable additional cc's
> > > > 
> > > > *** Remember to use Documentation/SubmitChecklist when testing your 
> > > > code ***
> > > > 
> > > > The -mm tree is included into linux-next and is updated
> > > > there every 3-4 working days
> > > > 
> > > > --
> > > > From: Shaohua Li 
> > > > Subject: mm: reclaim MADV_FREE pages
> > > > 
> > > > When memory pressure is high, we free MADV_FREE pages.  If the pages are
> > > > not dirty in pte, the pages could be freed immediately.  Otherwise we
> > > > can't reclaim them.  We put the pages back to anonumous LRU list (by
> > > > setting SwapBacked flag) and the pages will be reclaimed in normal 
> > > > swapout
> > > > way.
> > > > 
> > > > We use normal page reclaim policy.  Since MADV_FREE pages are put into
> > > > inactive file list, such pages and inactive file pages are reclaimed
> > > > according to their age.  This is expected, because we don't want to
> > > > reclaim too many MADV_FREE pages before used once pages.
> > > > 
> > > > Based on Minchan's original patch
> > > > 
> > > > Link: 
> > > > http://lkml.kernel.org/r/14b8eb1d3f6bf6cc492833f183ac8c304e560484.1487965799.git.s...@fb.com
> > > > Signed-off-by: Shaohua Li 
> > > > Acked-by: Minchan Kim 
> > > > Acked-by: Michal Hocko 
> > > > Acked-by: Johannes Weiner 
> > > > Acked-by: Hillf Danton 
> > > > Cc: Hugh Dickins 
> > > > Cc: Rik van Riel 
> > > > Cc: Mel Gorman 
> > > > Signed-off-by: Andrew Morton 
> > > > ---
> > > 
> > > < snip >
> > > 
> > > > @@ -1419,11 +1413,21 @@ static int try_to_unmap_one(struct page
> > > > VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> > > > PageSwapBacked(page),
> > > > page);
> > > >  
> > > > -   if (!PageDirty(page)) {
> > > > +   /*
> > > > +* swapin page could be clean, it has data 
> > > > stored in
> > > > +* swap. We can't silently discard it without 
> > > > setting
> > > > +* swap entry in the page table.
> > > > +*/
> > > > +   if (!PageDirty(page) && !PageSwapCache(page)) {
> > > > /* It's a freeable page by MADV_FREE */
> > > > dec_mm_counter(mm, MM_ANONPAGES);
> > > > -   rp->lazyfreed++;
> > > > goto discard;
> > > > +   } else if (!PageSwapBacked(page)) {
> > > > +   /* dirty MADV_FREE page */
> > > > +   set_pte_at(mm, address, pvmw.pte, 
> > > > pteval);
> > > > +   ret = SWAP_DIRTY;
> > > > +   page_vma_mapped_walk_done();
> > > > +   break;
> > > > }
> > > 
> > > There is no point to make this logic complicated with clean swapin-page.
> > > 
> > > Andrew,
> > > Could you fold below patch into the mm-reclaim-madv_free-pages.patch
> > > if others are not against?
> > > 
> > > Thanks.
> > > 
> > > From 0c28f6560fbc4e65da4f4a8cc4664ab9f7b11cf3 Mon Sep 17 00:00:00 2001
> > > From: Minchan Kim 
> > > Date: Fri, 3 Mar 2017 11:42:52 +0900
> > > Subject: [PATCH] mm: clean up lazyfree page handling
> > > 
> > > We can make it simple to understand without need to be aware of
> > > clean-swapin page.
> > > This patch just clean up lazyfree page handling in try_to_unmap_one.
> > > 
> > > Signed-off-by: Minchan Kim 
> > 
> > Agreed, this is a litle easier to follow.
> > 
> > Acked-by: Johannes Weiner 
> 
> Thanks, Johannes.
> 
> > 
> > > ---
> > >  mm/rmap.c | 22 +++---
> > >  1 file changed, 11 insertions(+), 11 deletions(-)
> > > 
> > > diff --git a/mm/rmap.c b/mm/rmap.c
> > > index bb45712..f7eab40 100644
> > > --- a/mm/rmap.c
> > > +++ b/mm/rmap.c
> > > @@ -1413,17 +1413,17 @@ static int

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-05 Thread Minchan Kim 
On Fri, Mar 03, 2017 at 10:18:51AM -0500, Johannes Weiner wrote:
> On Fri, Mar 03, 2017 at 11:52:37AM +0900, Minchan Kim wrote:
> > On Tue, Feb 28, 2017 at 04:32:38PM -0800, a...@linux-foundation.org wrote:
> > > 
> > > The patch titled
> > >  Subject: mm: reclaim MADV_FREE pages
> > > has been added to the -mm tree.  Its filename is
> > >  mm-reclaim-madv_free-pages.patch
> > > 
> > > This patch should soon appear at
> > > 
> > > http://ozlabs.org/~akpm/mmots/broken-out/mm-reclaim-madv_free-pages.patch
> > > and later at
> > > 
> > > http://ozlabs.org/~akpm/mmotm/broken-out/mm-reclaim-madv_free-pages.patch
> > > 
> > > Before you just go and hit "reply", please:
> > >a) Consider who else should be cc'ed
> > >b) Prefer to cc a suitable mailing list as well
> > >c) Ideally: find the original patch on the mailing list and do a
> > >   reply-to-all to that, adding suitable additional cc's
> > > 
> > > *** Remember to use Documentation/SubmitChecklist when testing your code 
> > > ***
> > > 
> > > The -mm tree is included into linux-next and is updated
> > > there every 3-4 working days
> > > 
> > > --
> > > From: Shaohua Li 
> > > Subject: mm: reclaim MADV_FREE pages
> > > 
> > > When memory pressure is high, we free MADV_FREE pages.  If the pages are
> > > not dirty in pte, the pages could be freed immediately.  Otherwise we
> > > can't reclaim them.  We put the pages back to anonumous LRU list (by
> > > setting SwapBacked flag) and the pages will be reclaimed in normal swapout
> > > way.
> > > 
> > > We use normal page reclaim policy.  Since MADV_FREE pages are put into
> > > inactive file list, such pages and inactive file pages are reclaimed
> > > according to their age.  This is expected, because we don't want to
> > > reclaim too many MADV_FREE pages before used once pages.
> > > 
> > > Based on Minchan's original patch
> > > 
> > > Link: 
> > > http://lkml.kernel.org/r/14b8eb1d3f6bf6cc492833f183ac8c304e560484.1487965799.git.s...@fb.com
> > > Signed-off-by: Shaohua Li 
> > > Acked-by: Minchan Kim 
> > > Acked-by: Michal Hocko 
> > > Acked-by: Johannes Weiner 
> > > Acked-by: Hillf Danton 
> > > Cc: Hugh Dickins 
> > > Cc: Rik van Riel 
> > > Cc: Mel Gorman 
> > > Signed-off-by: Andrew Morton 
> > > ---
> > 
> > < snip >
> > 
> > > @@ -1419,11 +1413,21 @@ static int try_to_unmap_one(struct page
> > >   VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> > > PageSwapBacked(page),
> > >   page);
> > >  
> > > - if (!PageDirty(page)) {
> > > + /*
> > > +  * swapin page could be clean, it has data stored in
> > > +  * swap. We can't silently discard it without setting
> > > +  * swap entry in the page table.
> > > +  */
> > > + if (!PageDirty(page) && !PageSwapCache(page)) {
> > >   /* It's a freeable page by MADV_FREE */
> > >   dec_mm_counter(mm, MM_ANONPAGES);
> > > - rp->lazyfreed++;
> > >   goto discard;
> > > + } else if (!PageSwapBacked(page)) {
> > > + /* dirty MADV_FREE page */
> > > + set_pte_at(mm, address, pvmw.pte, pteval);
> > > + ret = SWAP_DIRTY;
> > > + page_vma_mapped_walk_done();
> > > + break;
> > >   }
> > 
> > There is no point to make this logic complicated with clean swapin-page.
> > 
> > Andrew,
> > Could you fold below patch into the mm-reclaim-madv_free-pages.patch
> > if others are not against?
> > 
> > Thanks.
> > 
> > From 0c28f6560fbc4e65da4f4a8cc4664ab9f7b11cf3 Mon Sep 17 00:00:00 2001
> > From: Minchan Kim 
> > Date: Fri, 3 Mar 2017 11:42:52 +0900
> > Subject: [PATCH] mm: clean up lazyfree page handling
> > 
> > We can make it simple to understand without need to be aware of
> > clean-swapin page.
> > This patch just clean up lazyfree page handling in try_to_unmap_one.
> > 
> > Signed-off-by: Minchan Kim 
> 
> Agreed, this is a litle easier to follow.
> 
> Acked-by: Johannes Weiner 

Thanks, Johannes.

> 
> > ---
> >  mm/rmap.c | 22 +++---
> >  1 file changed, 11 insertions(+), 11 deletions(-)
> > 
> > diff --git a/mm/rmap.c b/mm/rmap.c
> > index bb45712..f7eab40 100644
> > --- a/mm/rmap.c
> > +++ b/mm/rmap.c
> > @@ -1413,17 +1413,17 @@ static int try_to_unmap_one(struct page *page, 
> > struct vm_area_struct *vma,
> > VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> > PageSwapBacked(page),
> >

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-05 Thread Minchan Kim 
On Fri, Mar 03, 2017 at 10:18:51AM -0500, Johannes Weiner wrote:
> On Fri, Mar 03, 2017 at 11:52:37AM +0900, Minchan Kim wrote:
> > On Tue, Feb 28, 2017 at 04:32:38PM -0800, a...@linux-foundation.org wrote:
> > > 
> > > The patch titled
> > >  Subject: mm: reclaim MADV_FREE pages
> > > has been added to the -mm tree.  Its filename is
> > >  mm-reclaim-madv_free-pages.patch
> > > 
> > > This patch should soon appear at
> > > 
> > > http://ozlabs.org/~akpm/mmots/broken-out/mm-reclaim-madv_free-pages.patch
> > > and later at
> > > 
> > > http://ozlabs.org/~akpm/mmotm/broken-out/mm-reclaim-madv_free-pages.patch
> > > 
> > > Before you just go and hit "reply", please:
> > >a) Consider who else should be cc'ed
> > >b) Prefer to cc a suitable mailing list as well
> > >c) Ideally: find the original patch on the mailing list and do a
> > >   reply-to-all to that, adding suitable additional cc's
> > > 
> > > *** Remember to use Documentation/SubmitChecklist when testing your code 
> > > ***
> > > 
> > > The -mm tree is included into linux-next and is updated
> > > there every 3-4 working days
> > > 
> > > --
> > > From: Shaohua Li 
> > > Subject: mm: reclaim MADV_FREE pages
> > > 
> > > When memory pressure is high, we free MADV_FREE pages.  If the pages are
> > > not dirty in pte, the pages could be freed immediately.  Otherwise we
> > > can't reclaim them.  We put the pages back to anonumous LRU list (by
> > > setting SwapBacked flag) and the pages will be reclaimed in normal swapout
> > > way.
> > > 
> > > We use normal page reclaim policy.  Since MADV_FREE pages are put into
> > > inactive file list, such pages and inactive file pages are reclaimed
> > > according to their age.  This is expected, because we don't want to
> > > reclaim too many MADV_FREE pages before used once pages.
> > > 
> > > Based on Minchan's original patch
> > > 
> > > Link: 
> > > http://lkml.kernel.org/r/14b8eb1d3f6bf6cc492833f183ac8c304e560484.1487965799.git.s...@fb.com
> > > Signed-off-by: Shaohua Li 
> > > Acked-by: Minchan Kim 
> > > Acked-by: Michal Hocko 
> > > Acked-by: Johannes Weiner 
> > > Acked-by: Hillf Danton 
> > > Cc: Hugh Dickins 
> > > Cc: Rik van Riel 
> > > Cc: Mel Gorman 
> > > Signed-off-by: Andrew Morton 
> > > ---
> > 
> > < snip >
> > 
> > > @@ -1419,11 +1413,21 @@ static int try_to_unmap_one(struct page
> > >   VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> > > PageSwapBacked(page),
> > >   page);
> > >  
> > > - if (!PageDirty(page)) {
> > > + /*
> > > +  * swapin page could be clean, it has data stored in
> > > +  * swap. We can't silently discard it without setting
> > > +  * swap entry in the page table.
> > > +  */
> > > + if (!PageDirty(page) && !PageSwapCache(page)) {
> > >   /* It's a freeable page by MADV_FREE */
> > >   dec_mm_counter(mm, MM_ANONPAGES);
> > > - rp->lazyfreed++;
> > >   goto discard;
> > > + } else if (!PageSwapBacked(page)) {
> > > + /* dirty MADV_FREE page */
> > > + set_pte_at(mm, address, pvmw.pte, pteval);
> > > + ret = SWAP_DIRTY;
> > > + page_vma_mapped_walk_done();
> > > + break;
> > >   }
> > 
> > There is no point to make this logic complicated with clean swapin-page.
> > 
> > Andrew,
> > Could you fold below patch into the mm-reclaim-madv_free-pages.patch
> > if others are not against?
> > 
> > Thanks.
> > 
> > From 0c28f6560fbc4e65da4f4a8cc4664ab9f7b11cf3 Mon Sep 17 00:00:00 2001
> > From: Minchan Kim 
> > Date: Fri, 3 Mar 2017 11:42:52 +0900
> > Subject: [PATCH] mm: clean up lazyfree page handling
> > 
> > We can make it simple to understand without need to be aware of
> > clean-swapin page.
> > This patch just clean up lazyfree page handling in try_to_unmap_one.
> > 
> > Signed-off-by: Minchan Kim 
> 
> Agreed, this is a litle easier to follow.
> 
> Acked-by: Johannes Weiner 

Thanks, Johannes.

> 
> > ---
> >  mm/rmap.c | 22 +++---
> >  1 file changed, 11 insertions(+), 11 deletions(-)
> > 
> > diff --git a/mm/rmap.c b/mm/rmap.c
> > index bb45712..f7eab40 100644
> > --- a/mm/rmap.c
> > +++ b/mm/rmap.c
> > @@ -1413,17 +1413,17 @@ static int try_to_unmap_one(struct page *page, 
> > struct vm_area_struct *vma,
> > VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> > PageSwapBacked(page),
> > page);
> 
> Since you're removing the PageSwapCache() check and we're now assuming
> that !swapbacked is not in the swapcache, can you modify this to check
> PageSwapBacked(page) != PageSwapCache(page)?
> 
> Better yet, change it into a warning and SWAP_FAIL.

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-03 Thread Shaohua Li 
On Fri, Mar 03, 2017 at 11:52:37AM +0900, Minchan Kim wrote:
> Hi,
> 
> On Tue, Feb 28, 2017 at 04:32:38PM -0800, a...@linux-foundation.org wrote:
> > 
> > The patch titled
> >  Subject: mm: reclaim MADV_FREE pages
> > has been added to the -mm tree.  Its filename is
> >  mm-reclaim-madv_free-pages.patch
> > 
> > This patch should soon appear at
> > 
> > https://urldefense.proofpoint.com/v2/url?u=http-3A__ozlabs.org_-7Eakpm_mmots_broken-2Dout_mm-2Dreclaim-2Dmadv-5Ffree-2Dpages.patch=DwIBAg=5VD0RTtNlTh3ycd41b3MUw=X13hAPkxmvBro1Ug8vcKHw=oMKTke-r00qQPnpEwo0Cn43po669gckvribhR9LQWf0=wzX_7IDavzBkFEMl7HDTMwrFXo1skB35mu0CjZmfFOg=
> >  
> > and later at
> > 
> > https://urldefense.proofpoint.com/v2/url?u=http-3A__ozlabs.org_-7Eakpm_mmotm_broken-2Dout_mm-2Dreclaim-2Dmadv-5Ffree-2Dpages.patch=DwIBAg=5VD0RTtNlTh3ycd41b3MUw=X13hAPkxmvBro1Ug8vcKHw=oMKTke-r00qQPnpEwo0Cn43po669gckvribhR9LQWf0=eUYtR1qeasKBGvuNWsZP6jE4XwoKwMb4CdKQU7OXGYM=
> >  
> > 
> > Before you just go and hit "reply", please:
> >a) Consider who else should be cc'ed
> >b) Prefer to cc a suitable mailing list as well
> >c) Ideally: find the original patch on the mailing list and do a
> >   reply-to-all to that, adding suitable additional cc's
> > 
> > *** Remember to use Documentation/SubmitChecklist when testing your code ***
> > 
> > The -mm tree is included into linux-next and is updated
> > there every 3-4 working days
> > 
> > --
> > From: Shaohua Li 
> > Subject: mm: reclaim MADV_FREE pages
> > 
> > When memory pressure is high, we free MADV_FREE pages.  If the pages are
> > not dirty in pte, the pages could be freed immediately.  Otherwise we
> > can't reclaim them.  We put the pages back to anonumous LRU list (by
> > setting SwapBacked flag) and the pages will be reclaimed in normal swapout
> > way.
> > 
> > We use normal page reclaim policy.  Since MADV_FREE pages are put into
> > inactive file list, such pages and inactive file pages are reclaimed
> > according to their age.  This is expected, because we don't want to
> > reclaim too many MADV_FREE pages before used once pages.
> > 
> > Based on Minchan's original patch
> > 
> > Link: 
> > http://lkml.kernel.org/r/14b8eb1d3f6bf6cc492833f183ac8c304e560484.1487965799.git.s...@fb.com
> > Signed-off-by: Shaohua Li 
> > Acked-by: Minchan Kim 
> > Acked-by: Michal Hocko 
> > Acked-by: Johannes Weiner 
> > Acked-by: Hillf Danton 
> > Cc: Hugh Dickins 
> > Cc: Rik van Riel 
> > Cc: Mel Gorman 
> > Signed-off-by: Andrew Morton 
> > ---
> 
> < snip >
> 
> > @@ -1419,11 +1413,21 @@ static int try_to_unmap_one(struct page
> > VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> > PageSwapBacked(page),
> > page);
> >  
> > -   if (!PageDirty(page)) {
> > +   /*
> > +* swapin page could be clean, it has data stored in
> > +* swap. We can't silently discard it without setting
> > +* swap entry in the page table.
> > +*/
> > +   if (!PageDirty(page) && !PageSwapCache(page)) {
> > /* It's a freeable page by MADV_FREE */
> > dec_mm_counter(mm, MM_ANONPAGES);
> > -   rp->lazyfreed++;
> > goto discard;
> > +   } else if (!PageSwapBacked(page)) {
> > +   /* dirty MADV_FREE page */
> > +   set_pte_at(mm, address, pvmw.pte, pteval);
> > +   ret = SWAP_DIRTY;
> > +   page_vma_mapped_walk_done();
> > +   break;
> > }
> 
> There is no point to make this logic complicated with clean swapin-page.
> 
> Andrew,
> Could you fold below patch into the mm-reclaim-madv_free-pages.patch
> if others are not against?
> 
> Thanks.
> 
> From 0c28f6560fbc4e65da4f4a8cc4664ab9f7b11cf3 Mon Sep 17 00:00:00 2001
> From: Minchan Kim 
> Date: Fri, 3 Mar 2017 11:42:52 +0900
> Subject: [PATCH] mm: clean up lazyfree page handling
> 
> We can make it simple to understand without need to be aware of
> clean-swapin page.
> This patch just clean up lazyfree page handling in try_to_unmap_one.

Looks good, thanks!

Reviewed-by: Shaohua Li 
 
> Signed-off-by: Minchan Kim 
> ---
>  mm/rmap.c | 22 +++---
>  1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index bb45712..f7eab40 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1413,17 +1413,17 @@ static int try_to_unmap_one(struct page *page, struct 
> vm_area_struct *vma,
>

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-03 Thread Shaohua Li 
On Fri, Mar 03, 2017 at 11:52:37AM +0900, Minchan Kim wrote:
> Hi,
> 
> On Tue, Feb 28, 2017 at 04:32:38PM -0800, a...@linux-foundation.org wrote:
> > 
> > The patch titled
> >  Subject: mm: reclaim MADV_FREE pages
> > has been added to the -mm tree.  Its filename is
> >  mm-reclaim-madv_free-pages.patch
> > 
> > This patch should soon appear at
> > 
> > https://urldefense.proofpoint.com/v2/url?u=http-3A__ozlabs.org_-7Eakpm_mmots_broken-2Dout_mm-2Dreclaim-2Dmadv-5Ffree-2Dpages.patch=DwIBAg=5VD0RTtNlTh3ycd41b3MUw=X13hAPkxmvBro1Ug8vcKHw=oMKTke-r00qQPnpEwo0Cn43po669gckvribhR9LQWf0=wzX_7IDavzBkFEMl7HDTMwrFXo1skB35mu0CjZmfFOg=
> >  
> > and later at
> > 
> > https://urldefense.proofpoint.com/v2/url?u=http-3A__ozlabs.org_-7Eakpm_mmotm_broken-2Dout_mm-2Dreclaim-2Dmadv-5Ffree-2Dpages.patch=DwIBAg=5VD0RTtNlTh3ycd41b3MUw=X13hAPkxmvBro1Ug8vcKHw=oMKTke-r00qQPnpEwo0Cn43po669gckvribhR9LQWf0=eUYtR1qeasKBGvuNWsZP6jE4XwoKwMb4CdKQU7OXGYM=
> >  
> > 
> > Before you just go and hit "reply", please:
> >a) Consider who else should be cc'ed
> >b) Prefer to cc a suitable mailing list as well
> >c) Ideally: find the original patch on the mailing list and do a
> >   reply-to-all to that, adding suitable additional cc's
> > 
> > *** Remember to use Documentation/SubmitChecklist when testing your code ***
> > 
> > The -mm tree is included into linux-next and is updated
> > there every 3-4 working days
> > 
> > --
> > From: Shaohua Li 
> > Subject: mm: reclaim MADV_FREE pages
> > 
> > When memory pressure is high, we free MADV_FREE pages.  If the pages are
> > not dirty in pte, the pages could be freed immediately.  Otherwise we
> > can't reclaim them.  We put the pages back to anonumous LRU list (by
> > setting SwapBacked flag) and the pages will be reclaimed in normal swapout
> > way.
> > 
> > We use normal page reclaim policy.  Since MADV_FREE pages are put into
> > inactive file list, such pages and inactive file pages are reclaimed
> > according to their age.  This is expected, because we don't want to
> > reclaim too many MADV_FREE pages before used once pages.
> > 
> > Based on Minchan's original patch
> > 
> > Link: 
> > http://lkml.kernel.org/r/14b8eb1d3f6bf6cc492833f183ac8c304e560484.1487965799.git.s...@fb.com
> > Signed-off-by: Shaohua Li 
> > Acked-by: Minchan Kim 
> > Acked-by: Michal Hocko 
> > Acked-by: Johannes Weiner 
> > Acked-by: Hillf Danton 
> > Cc: Hugh Dickins 
> > Cc: Rik van Riel 
> > Cc: Mel Gorman 
> > Signed-off-by: Andrew Morton 
> > ---
> 
> < snip >
> 
> > @@ -1419,11 +1413,21 @@ static int try_to_unmap_one(struct page
> > VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> > PageSwapBacked(page),
> > page);
> >  
> > -   if (!PageDirty(page)) {
> > +   /*
> > +* swapin page could be clean, it has data stored in
> > +* swap. We can't silently discard it without setting
> > +* swap entry in the page table.
> > +*/
> > +   if (!PageDirty(page) && !PageSwapCache(page)) {
> > /* It's a freeable page by MADV_FREE */
> > dec_mm_counter(mm, MM_ANONPAGES);
> > -   rp->lazyfreed++;
> > goto discard;
> > +   } else if (!PageSwapBacked(page)) {
> > +   /* dirty MADV_FREE page */
> > +   set_pte_at(mm, address, pvmw.pte, pteval);
> > +   ret = SWAP_DIRTY;
> > +   page_vma_mapped_walk_done();
> > +   break;
> > }
> 
> There is no point to make this logic complicated with clean swapin-page.
> 
> Andrew,
> Could you fold below patch into the mm-reclaim-madv_free-pages.patch
> if others are not against?
> 
> Thanks.
> 
> From 0c28f6560fbc4e65da4f4a8cc4664ab9f7b11cf3 Mon Sep 17 00:00:00 2001
> From: Minchan Kim 
> Date: Fri, 3 Mar 2017 11:42:52 +0900
> Subject: [PATCH] mm: clean up lazyfree page handling
> 
> We can make it simple to understand without need to be aware of
> clean-swapin page.
> This patch just clean up lazyfree page handling in try_to_unmap_one.

Looks good, thanks!

Reviewed-by: Shaohua Li 
 
> Signed-off-by: Minchan Kim 
> ---
>  mm/rmap.c | 22 +++---
>  1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index bb45712..f7eab40 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1413,17 +1413,17 @@ static int try_to_unmap_one(struct page *page, struct 
> vm_area_struct *vma,
>   VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> PageSwapBacked(page),
>   page);
>  
> - /*
> -  * swapin page could be clean, it has data stored in
> -  * swap. We

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-03 Thread Johannes Weiner 
On Fri, Mar 03, 2017 at 11:52:37AM +0900, Minchan Kim wrote:
> On Tue, Feb 28, 2017 at 04:32:38PM -0800, a...@linux-foundation.org wrote:
> > 
> > The patch titled
> >  Subject: mm: reclaim MADV_FREE pages
> > has been added to the -mm tree.  Its filename is
> >  mm-reclaim-madv_free-pages.patch
> > 
> > This patch should soon appear at
> > 
> > http://ozlabs.org/~akpm/mmots/broken-out/mm-reclaim-madv_free-pages.patch
> > and later at
> > 
> > http://ozlabs.org/~akpm/mmotm/broken-out/mm-reclaim-madv_free-pages.patch
> > 
> > Before you just go and hit "reply", please:
> >a) Consider who else should be cc'ed
> >b) Prefer to cc a suitable mailing list as well
> >c) Ideally: find the original patch on the mailing list and do a
> >   reply-to-all to that, adding suitable additional cc's
> > 
> > *** Remember to use Documentation/SubmitChecklist when testing your code ***
> > 
> > The -mm tree is included into linux-next and is updated
> > there every 3-4 working days
> > 
> > --
> > From: Shaohua Li 
> > Subject: mm: reclaim MADV_FREE pages
> > 
> > When memory pressure is high, we free MADV_FREE pages.  If the pages are
> > not dirty in pte, the pages could be freed immediately.  Otherwise we
> > can't reclaim them.  We put the pages back to anonumous LRU list (by
> > setting SwapBacked flag) and the pages will be reclaimed in normal swapout
> > way.
> > 
> > We use normal page reclaim policy.  Since MADV_FREE pages are put into
> > inactive file list, such pages and inactive file pages are reclaimed
> > according to their age.  This is expected, because we don't want to
> > reclaim too many MADV_FREE pages before used once pages.
> > 
> > Based on Minchan's original patch
> > 
> > Link: 
> > http://lkml.kernel.org/r/14b8eb1d3f6bf6cc492833f183ac8c304e560484.1487965799.git.s...@fb.com
> > Signed-off-by: Shaohua Li 
> > Acked-by: Minchan Kim 
> > Acked-by: Michal Hocko 
> > Acked-by: Johannes Weiner 
> > Acked-by: Hillf Danton 
> > Cc: Hugh Dickins 
> > Cc: Rik van Riel 
> > Cc: Mel Gorman 
> > Signed-off-by: Andrew Morton 
> > ---
> 
> < snip >
> 
> > @@ -1419,11 +1413,21 @@ static int try_to_unmap_one(struct page
> > VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> > PageSwapBacked(page),
> > page);
> >  
> > -   if (!PageDirty(page)) {
> > +   /*
> > +* swapin page could be clean, it has data stored in
> > +* swap. We can't silently discard it without setting
> > +* swap entry in the page table.
> > +*/
> > +   if (!PageDirty(page) && !PageSwapCache(page)) {
> > /* It's a freeable page by MADV_FREE */
> > dec_mm_counter(mm, MM_ANONPAGES);
> > -   rp->lazyfreed++;
> > goto discard;
> > +   } else if (!PageSwapBacked(page)) {
> > +   /* dirty MADV_FREE page */
> > +   set_pte_at(mm, address, pvmw.pte, pteval);
> > +   ret = SWAP_DIRTY;
> > +   page_vma_mapped_walk_done();
> > +   break;
> > }
> 
> There is no point to make this logic complicated with clean swapin-page.
> 
> Andrew,
> Could you fold below patch into the mm-reclaim-madv_free-pages.patch
> if others are not against?
> 
> Thanks.
> 
> From 0c28f6560fbc4e65da4f4a8cc4664ab9f7b11cf3 Mon Sep 17 00:00:00 2001
> From: Minchan Kim 
> Date: Fri, 3 Mar 2017 11:42:52 +0900
> Subject: [PATCH] mm: clean up lazyfree page handling
> 
> We can make it simple to understand without need to be aware of
> clean-swapin page.
> This patch just clean up lazyfree page handling in try_to_unmap_one.
> 
> Signed-off-by: Minchan Kim 

Agreed, this is a litle easier to follow.

Acked-by: Johannes Weiner 

> ---
>  mm/rmap.c | 22 +++---
>  1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index bb45712..f7eab40 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1413,17 +1413,17 @@ static int try_to_unmap_one(struct page *page, struct 
> vm_area_struct *vma,
>   VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> PageSwapBacked(page),
>   page);

Since you're removing the PageSwapCache() check and we're now assuming
that !swapbacked is not in the swapcache, can you modify this to check
PageSwapBacked(page) != PageSwapCache(page)?

Better yet, change it into a warning and SWAP_FAIL.

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-03 Thread Johannes Weiner 
On Fri, Mar 03, 2017 at 11:52:37AM +0900, Minchan Kim wrote:
> On Tue, Feb 28, 2017 at 04:32:38PM -0800, a...@linux-foundation.org wrote:
> > 
> > The patch titled
> >  Subject: mm: reclaim MADV_FREE pages
> > has been added to the -mm tree.  Its filename is
> >  mm-reclaim-madv_free-pages.patch
> > 
> > This patch should soon appear at
> > 
> > http://ozlabs.org/~akpm/mmots/broken-out/mm-reclaim-madv_free-pages.patch
> > and later at
> > 
> > http://ozlabs.org/~akpm/mmotm/broken-out/mm-reclaim-madv_free-pages.patch
> > 
> > Before you just go and hit "reply", please:
> >a) Consider who else should be cc'ed
> >b) Prefer to cc a suitable mailing list as well
> >c) Ideally: find the original patch on the mailing list and do a
> >   reply-to-all to that, adding suitable additional cc's
> > 
> > *** Remember to use Documentation/SubmitChecklist when testing your code ***
> > 
> > The -mm tree is included into linux-next and is updated
> > there every 3-4 working days
> > 
> > --
> > From: Shaohua Li 
> > Subject: mm: reclaim MADV_FREE pages
> > 
> > When memory pressure is high, we free MADV_FREE pages.  If the pages are
> > not dirty in pte, the pages could be freed immediately.  Otherwise we
> > can't reclaim them.  We put the pages back to anonumous LRU list (by
> > setting SwapBacked flag) and the pages will be reclaimed in normal swapout
> > way.
> > 
> > We use normal page reclaim policy.  Since MADV_FREE pages are put into
> > inactive file list, such pages and inactive file pages are reclaimed
> > according to their age.  This is expected, because we don't want to
> > reclaim too many MADV_FREE pages before used once pages.
> > 
> > Based on Minchan's original patch
> > 
> > Link: 
> > http://lkml.kernel.org/r/14b8eb1d3f6bf6cc492833f183ac8c304e560484.1487965799.git.s...@fb.com
> > Signed-off-by: Shaohua Li 
> > Acked-by: Minchan Kim 
> > Acked-by: Michal Hocko 
> > Acked-by: Johannes Weiner 
> > Acked-by: Hillf Danton 
> > Cc: Hugh Dickins 
> > Cc: Rik van Riel 
> > Cc: Mel Gorman 
> > Signed-off-by: Andrew Morton 
> > ---
> 
> < snip >
> 
> > @@ -1419,11 +1413,21 @@ static int try_to_unmap_one(struct page
> > VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> > PageSwapBacked(page),
> > page);
> >  
> > -   if (!PageDirty(page)) {
> > +   /*
> > +* swapin page could be clean, it has data stored in
> > +* swap. We can't silently discard it without setting
> > +* swap entry in the page table.
> > +*/
> > +   if (!PageDirty(page) && !PageSwapCache(page)) {
> > /* It's a freeable page by MADV_FREE */
> > dec_mm_counter(mm, MM_ANONPAGES);
> > -   rp->lazyfreed++;
> > goto discard;
> > +   } else if (!PageSwapBacked(page)) {
> > +   /* dirty MADV_FREE page */
> > +   set_pte_at(mm, address, pvmw.pte, pteval);
> > +   ret = SWAP_DIRTY;
> > +   page_vma_mapped_walk_done();
> > +   break;
> > }
> 
> There is no point to make this logic complicated with clean swapin-page.
> 
> Andrew,
> Could you fold below patch into the mm-reclaim-madv_free-pages.patch
> if others are not against?
> 
> Thanks.
> 
> From 0c28f6560fbc4e65da4f4a8cc4664ab9f7b11cf3 Mon Sep 17 00:00:00 2001
> From: Minchan Kim 
> Date: Fri, 3 Mar 2017 11:42:52 +0900
> Subject: [PATCH] mm: clean up lazyfree page handling
> 
> We can make it simple to understand without need to be aware of
> clean-swapin page.
> This patch just clean up lazyfree page handling in try_to_unmap_one.
> 
> Signed-off-by: Minchan Kim 

Agreed, this is a litle easier to follow.

Acked-by: Johannes Weiner 

> ---
>  mm/rmap.c | 22 +++---
>  1 file changed, 11 insertions(+), 11 deletions(-)
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index bb45712..f7eab40 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1413,17 +1413,17 @@ static int try_to_unmap_one(struct page *page, struct 
> vm_area_struct *vma,
>   VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> PageSwapBacked(page),
>   page);

Since you're removing the PageSwapCache() check and we're now assuming
that !swapbacked is not in the swapcache, can you modify this to check
PageSwapBacked(page) != PageSwapCache(page)?

Better yet, change it into a warning and SWAP_FAIL.

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-02 Thread Minchan Kim 
Hi,

On Tue, Feb 28, 2017 at 04:32:38PM -0800, a...@linux-foundation.org wrote:
> 
> The patch titled
>  Subject: mm: reclaim MADV_FREE pages
> has been added to the -mm tree.  Its filename is
>  mm-reclaim-madv_free-pages.patch
> 
> This patch should soon appear at
> http://ozlabs.org/~akpm/mmots/broken-out/mm-reclaim-madv_free-pages.patch
> and later at
> http://ozlabs.org/~akpm/mmotm/broken-out/mm-reclaim-madv_free-pages.patch
> 
> Before you just go and hit "reply", please:
>a) Consider who else should be cc'ed
>b) Prefer to cc a suitable mailing list as well
>c) Ideally: find the original patch on the mailing list and do a
>   reply-to-all to that, adding suitable additional cc's
> 
> *** Remember to use Documentation/SubmitChecklist when testing your code ***
> 
> The -mm tree is included into linux-next and is updated
> there every 3-4 working days
> 
> --
> From: Shaohua Li 
> Subject: mm: reclaim MADV_FREE pages
> 
> When memory pressure is high, we free MADV_FREE pages.  If the pages are
> not dirty in pte, the pages could be freed immediately.  Otherwise we
> can't reclaim them.  We put the pages back to anonumous LRU list (by
> setting SwapBacked flag) and the pages will be reclaimed in normal swapout
> way.
> 
> We use normal page reclaim policy.  Since MADV_FREE pages are put into
> inactive file list, such pages and inactive file pages are reclaimed
> according to their age.  This is expected, because we don't want to
> reclaim too many MADV_FREE pages before used once pages.
> 
> Based on Minchan's original patch
> 
> Link: 
> http://lkml.kernel.org/r/14b8eb1d3f6bf6cc492833f183ac8c304e560484.1487965799.git.s...@fb.com
> Signed-off-by: Shaohua Li 
> Acked-by: Minchan Kim 
> Acked-by: Michal Hocko 
> Acked-by: Johannes Weiner 
> Acked-by: Hillf Danton 
> Cc: Hugh Dickins 
> Cc: Rik van Riel 
> Cc: Mel Gorman 
> Signed-off-by: Andrew Morton 
> ---

< snip >

> @@ -1419,11 +1413,21 @@ static int try_to_unmap_one(struct page
>   VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> PageSwapBacked(page),
>   page);
>  
> - if (!PageDirty(page)) {
> + /*
> +  * swapin page could be clean, it has data stored in
> +  * swap. We can't silently discard it without setting
> +  * swap entry in the page table.
> +  */
> + if (!PageDirty(page) && !PageSwapCache(page)) {
>   /* It's a freeable page by MADV_FREE */
>   dec_mm_counter(mm, MM_ANONPAGES);
> - rp->lazyfreed++;
>   goto discard;
> + } else if (!PageSwapBacked(page)) {
> + /* dirty MADV_FREE page */
> + set_pte_at(mm, address, pvmw.pte, pteval);
> + ret = SWAP_DIRTY;
> + page_vma_mapped_walk_done();
> + break;
>   }

There is no point to make this logic complicated with clean swapin-page.

Andrew,
Could you fold below patch into the mm-reclaim-madv_free-pages.patch
if others are not against?

Thanks.

>From 0c28f6560fbc4e65da4f4a8cc4664ab9f7b11cf3 Mon Sep 17 00:00:00 2001
From: Minchan Kim 
Date: Fri, 3 Mar 2017 11:42:52 +0900
Subject: [PATCH] mm: clean up lazyfree page handling

We can make it simple to understand without need to be aware of
clean-swapin page.
This patch just clean up lazyfree page handling in try_to_unmap_one.

Signed-off-by: Minchan Kim 
---
 mm/rmap.c | 22 +++---
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index bb45712..f7eab40 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1413,17 +1413,17 @@ static int try_to_unmap_one(struct page *page, struct 
vm_area_struct *vma,
VM_BUG_ON_PAGE(!PageSwapCache(page) && 
PageSwapBacked(page),
page);
 
-   /*
-* swapin page could be clean, it has data stored in
-* swap. We can't silently discard it without setting
-* swap entry in the page table.
-*/
-   if (!PageDirty(page) && !PageSwapCache(page)) {
-   /* It's a freeable page by MADV_FREE */
-   dec_mm_counter(mm, MM_ANONPAGES);
-   goto discard;
-   } else if (!PageSwapBacked(page)) {
-

Re: + mm-reclaim-madv_free-pages.patch added to -mm tree

2017-03-02 Thread Minchan Kim 
Hi,

On Tue, Feb 28, 2017 at 04:32:38PM -0800, a...@linux-foundation.org wrote:
> 
> The patch titled
>  Subject: mm: reclaim MADV_FREE pages
> has been added to the -mm tree.  Its filename is
>  mm-reclaim-madv_free-pages.patch
> 
> This patch should soon appear at
> http://ozlabs.org/~akpm/mmots/broken-out/mm-reclaim-madv_free-pages.patch
> and later at
> http://ozlabs.org/~akpm/mmotm/broken-out/mm-reclaim-madv_free-pages.patch
> 
> Before you just go and hit "reply", please:
>a) Consider who else should be cc'ed
>b) Prefer to cc a suitable mailing list as well
>c) Ideally: find the original patch on the mailing list and do a
>   reply-to-all to that, adding suitable additional cc's
> 
> *** Remember to use Documentation/SubmitChecklist when testing your code ***
> 
> The -mm tree is included into linux-next and is updated
> there every 3-4 working days
> 
> --
> From: Shaohua Li 
> Subject: mm: reclaim MADV_FREE pages
> 
> When memory pressure is high, we free MADV_FREE pages.  If the pages are
> not dirty in pte, the pages could be freed immediately.  Otherwise we
> can't reclaim them.  We put the pages back to anonumous LRU list (by
> setting SwapBacked flag) and the pages will be reclaimed in normal swapout
> way.
> 
> We use normal page reclaim policy.  Since MADV_FREE pages are put into
> inactive file list, such pages and inactive file pages are reclaimed
> according to their age.  This is expected, because we don't want to
> reclaim too many MADV_FREE pages before used once pages.
> 
> Based on Minchan's original patch
> 
> Link: 
> http://lkml.kernel.org/r/14b8eb1d3f6bf6cc492833f183ac8c304e560484.1487965799.git.s...@fb.com
> Signed-off-by: Shaohua Li 
> Acked-by: Minchan Kim 
> Acked-by: Michal Hocko 
> Acked-by: Johannes Weiner 
> Acked-by: Hillf Danton 
> Cc: Hugh Dickins 
> Cc: Rik van Riel 
> Cc: Mel Gorman 
> Signed-off-by: Andrew Morton 
> ---

< snip >

> @@ -1419,11 +1413,21 @@ static int try_to_unmap_one(struct page
>   VM_BUG_ON_PAGE(!PageSwapCache(page) && 
> PageSwapBacked(page),
>   page);
>  
> - if (!PageDirty(page)) {
> + /*
> +  * swapin page could be clean, it has data stored in
> +  * swap. We can't silently discard it without setting
> +  * swap entry in the page table.
> +  */
> + if (!PageDirty(page) && !PageSwapCache(page)) {
>   /* It's a freeable page by MADV_FREE */
>   dec_mm_counter(mm, MM_ANONPAGES);
> - rp->lazyfreed++;
>   goto discard;
> + } else if (!PageSwapBacked(page)) {
> + /* dirty MADV_FREE page */
> + set_pte_at(mm, address, pvmw.pte, pteval);
> + ret = SWAP_DIRTY;
> + page_vma_mapped_walk_done();
> + break;
>   }

There is no point to make this logic complicated with clean swapin-page.

Andrew,
Could you fold below patch into the mm-reclaim-madv_free-pages.patch
if others are not against?

Thanks.

>From 0c28f6560fbc4e65da4f4a8cc4664ab9f7b11cf3 Mon Sep 17 00:00:00 2001
From: Minchan Kim 
Date: Fri, 3 Mar 2017 11:42:52 +0900
Subject: [PATCH] mm: clean up lazyfree page handling

We can make it simple to understand without need to be aware of
clean-swapin page.
This patch just clean up lazyfree page handling in try_to_unmap_one.

Signed-off-by: Minchan Kim 
---
 mm/rmap.c | 22 +++---
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index bb45712..f7eab40 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1413,17 +1413,17 @@ static int try_to_unmap_one(struct page *page, struct 
vm_area_struct *vma,
VM_BUG_ON_PAGE(!PageSwapCache(page) && 
PageSwapBacked(page),
page);
 
-   /*
-* swapin page could be clean, it has data stored in
-* swap. We can't silently discard it without setting
-* swap entry in the page table.
-*/
-   if (!PageDirty(page) && !PageSwapCache(page)) {
-   /* It's a freeable page by MADV_FREE */
-   dec_mm_counter(mm, MM_ANONPAGES);
-   goto discard;
-   } else if (!PageSwapBacked(page)) {
-   /* dirty MADV_FREE page */
+   /* MADV_FREE page check */
+   if (!PageSwapBacked(page)) {
+   if (!PageDirty(page)) {
+