[PATCH v9 00/21] per lruvec lru_lock for memcg

[PATCH v9 00/21] per lruvec lru_lock for memcg

[Alex Shi]

Hi all,

This patchset mainly includes 3 parts:
1, some code cleanup and minimum optimization as a preparation.
2, use TestCleanPageLRU as page isolation's precondition
3, replace per node lru_lock with per memcg per node lru_lock

The keypoint of this patchset is moving lru_lock into lruvec, give a 
lru_lock for each of lruvec, thus bring a lru_lock for each of memcg 
per node. So on a large node machine, each of memcg don't suffer from
per node pgdat->lru_lock waiting. They could go fast with their self
lru_lock now.

Since lruvec belongs to each memcg, the critical point is to keep
page's memcg stable, so we take PageLRU as its isolation's precondition.
Thanks for Johannes Weiner help and suggestion!

Following Daniel Jordan's suggestion, I have run 208 'dd' with on 104
containers on a 2s * 26cores * HT box with a modefied case:
  https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/tree/case-lru-file-readtwice

With this patchset, the readtwice performance increased about 80%
in concurrent containers.

Thanks Hugh Dickins and Konstantin Khlebnikov, they both brought this
idea 8 years ago, and others who give comments as well: Daniel Jordan, 
Mel Gorman, Shakeel Butt, Matthew Wilcox etc.

Thanks for Testing support from Intel 0day and Rong Chen, Fengguang Wu,
and Yun Wang.

v9,
  a, use TestCleanPageLRU as page isolation's precondition, that
     resolved the page's memcg stable problem, Thanks Johannes Weiner!
  b, few more code clean up patches

v8,
  a, redo lock_page_lru cleanup as Konstantin Khlebnikov suggested.
  b, fix a bug in lruvec_memcg_debug, reported by Hugh Dickins

...

v1: initial version, aim testing show 5% performance increase on a 16 threads box.

Alex Shi (19):
  mm/vmscan: remove unnecessary lruvec adding
  mm/memcg: fold lock_page_lru into commit_charge
  mm/page_idle: no unlikely double check for idle page counting
  mm/thp: move lru_add_page_tail func to huge_memory.c
  mm/thp: clean up lru_add_page_tail
  mm/thp: narrow lru locking
  mm/lru: introduce TestClearPageLRU
  mm/lru: add page isolation precondition in __isolate_lru_page
  mm/mlock: ClearPageLRU before get lru lock in munlock page isolation
  mm/lru: take PageLRU first in moving page between lru lists
  mm/memcg: move SetPageLRU out of lru_lock in commit_charge
  mm/mlock: clean up __munlock_isolate_lru_page
  mm/lru: replace pgdat lru_lock with lruvec lock
  mm/lru: introduce the relock_page_lruvec function
  mm/mlock: optimize munlock_pagevec by relocking
  mm/swap: only change the lru_lock iff page's lruvec is different
  mm/pgdat: remove pgdat lru_lock
  mm/lru: add debug checking for page memcg moving
  mm/memcg: add debug checking in lock_page_memcg

Hugh Dickins (1):
  mm/lru: revise the comments of lru_lock

 Documentation/admin-guide/cgroup-v1/memcg_test.rst |  15 +-
 Documentation/admin-guide/cgroup-v1/memory.rst     |   8 +-
 Documentation/trace/events-kmem.rst                |   2 +-
 Documentation/vm/unevictable-lru.rst               |  22 +--
 include/linux/memcontrol.h                         |  77 ++++++++++
 include/linux/mm_types.h                           |   2 +-
 include/linux/mmzone.h                             |   5 +-
 include/linux/page-flags.h                         |   1 +
 include/linux/swap.h                               |   6 +-
 mm/compaction.c                                    |  78 ++++++----
 mm/filemap.c                                       |   4 +-
 mm/huge_memory.c                                   |  54 +++++--
 mm/memcontrol.c                                    | 110 +++++++++-----
 mm/mlock.c                                         |  88 ++++++-----
 mm/mmzone.c                                        |   1 +
 mm/page_alloc.c                                    |   1 -
 mm/page_idle.c                                     |   8 -
 mm/rmap.c                                          |   2 +-
 mm/swap.c                                          | 160 +++++++-------------
 mm/vmscan.c                                        | 163 +++++++++++----------
 20 files changed, 446 insertions(+), 361 deletions(-)

-- 
1.8.3.1

[PATCH v9 01/20] mm/vmscan: remove unnecessary lruvec adding

[Alex Shi]

We don't have to add a freeable page into lru and then remove from it.
This change saves a couple of actions and makes the moving more clear.

The SetPageLRU needs to be kept here for list intergrity.
Otherwise:
 #0 mave_pages_to_lru              #1 release_pages
                                   if (put_page_testzero())
 if !put_page_testzero
                                     !PageLRU //skip lru_lock
                                       list_add(&page->lru,)
   list_add(&page->lru,) //corrupt

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/vmscan.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 876370565455..dcdd33f65f43 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1838,26 +1838,29 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 	while (!list_empty(list)) {
 		page = lru_to_page(list);
 		VM_BUG_ON_PAGE(PageLRU(page), page);
+		list_del(&page->lru);
 		if (unlikely(!page_evictable(page))) {
-			list_del(&page->lru);
 			spin_unlock_irq(&pgdat->lru_lock);
 			putback_lru_page(page);
 			spin_lock_irq(&pgdat->lru_lock);
 			continue;
 		}
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
+		/*
+		 * The SetPageLRU needs to be kept here for list intergrity.
+		 * Otherwise:
+		 *   #0 mave_pages_to_lru              #1 release_pages
+		 *				       if (put_page_testzero())
+		 *   if !put_page_testzero
+		 *				         !PageLRU //skip lru_lock
+		 *                                         list_add(&page->lru,)
+		 *     list_add(&page->lru,) //corrupt
+		 */
 		SetPageLRU(page);
-		lru = page_lru(page);
-
-		nr_pages = hpage_nr_pages(page);
-		update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
-		list_move(&page->lru, &lruvec->lists[lru]);
 
-		if (put_page_testzero(page)) {
+		if (unlikely(put_page_testzero(page))) {
 			__ClearPageLRU(page);
 			__ClearPageActive(page);
-			del_page_from_lru_list(page, lruvec, lru);
 
 			if (unlikely(PageCompound(page))) {
 				spin_unlock_irq(&pgdat->lru_lock);
@@ -1865,9 +1868,16 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 				spin_lock_irq(&pgdat->lru_lock);
 			} else
 				list_add(&page->lru, &pages_to_free);
-		} else {
-			nr_moved += nr_pages;
+			continue;
 		}
+
+		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+		lru = page_lru(page);
+		nr_pages = hpage_nr_pages(page);
+
+		update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
+		list_add(&page->lru, &lruvec->lists[lru]);
+		nr_moved += nr_pages;
 	}
 
 	/*
-- 
1.8.3.1

[PATCH v9 02/20] mm/memcg: fold lock_page_lru into commit_charge

[Alex Shi]

As Konstantin Khlebnikov mentioned:

	Also I don't like these functions:
	- called lock/unlock but actually also isolates
	- used just once
	- pgdat evaluated twice

Cleanup and fold these functions into commit_charge. It also reduces
lock time while lrucare && !PageLRU.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/memcontrol.c | 57 ++++++++++++++++++++-------------------------------------
 1 file changed, 20 insertions(+), 37 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d09776cd6e10..875e2aebcde7 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2572,41 +2572,11 @@ static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
 	css_put_many(&memcg->css, nr_pages);
 }
 
-static void lock_page_lru(struct page *page, int *isolated)
-{
-	pg_data_t *pgdat = page_pgdat(page);
-
-	spin_lock_irq(&pgdat->lru_lock);
-	if (PageLRU(page)) {
-		struct lruvec *lruvec;
-
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
-		ClearPageLRU(page);
-		del_page_from_lru_list(page, lruvec, page_lru(page));
-		*isolated = 1;
-	} else
-		*isolated = 0;
-}
-
-static void unlock_page_lru(struct page *page, int isolated)
-{
-	pg_data_t *pgdat = page_pgdat(page);
-
-	if (isolated) {
-		struct lruvec *lruvec;
-
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
-		VM_BUG_ON_PAGE(PageLRU(page), page);
-		SetPageLRU(page);
-		add_page_to_lru_list(page, lruvec, page_lru(page));
-	}
-	spin_unlock_irq(&pgdat->lru_lock);
-}
-
 static void commit_charge(struct page *page, struct mem_cgroup *memcg,
 			  bool lrucare)
 {
-	int isolated;
+	struct lruvec *lruvec = NULL;
+	pg_data_t *pgdat;
 
 	VM_BUG_ON_PAGE(page->mem_cgroup, page);
 
@@ -2614,9 +2584,17 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
 	 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
 	 * may already be on some other mem_cgroup's LRU.  Take care of it.
 	 */
-	if (lrucare)
-		lock_page_lru(page, &isolated);
-
+	if (lrucare) {
+		pgdat = page_pgdat(page);
+		spin_lock_irq(&pgdat->lru_lock);
+
+		if (PageLRU(page)) {
+			lruvec = mem_cgroup_page_lruvec(page, pgdat);
+			ClearPageLRU(page);
+			del_page_from_lru_list(page, lruvec, page_lru(page));
+		} else
+			spin_unlock_irq(&pgdat->lru_lock);
+	}
 	/*
 	 * Nobody should be changing or seriously looking at
 	 * page->mem_cgroup at this point:
@@ -2633,8 +2611,13 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
 	 */
 	page->mem_cgroup = memcg;
 
-	if (lrucare)
-		unlock_page_lru(page, isolated);
+	if (lrucare && lruvec) {
+		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+		VM_BUG_ON_PAGE(PageLRU(page), page);
+		SetPageLRU(page);
+		add_page_to_lru_list(page, lruvec, page_lru(page));
+		spin_unlock_irq(&pgdat->lru_lock);
+	}
 }
 
 #ifdef CONFIG_MEMCG_KMEM
-- 
1.8.3.1

[PATCH v9 03/20] mm/page_idle: no unlikely double check for idle page counting

[Alex Shi]

As func comments mentioned, few isolated page missing be tolerated.
So why not do further to drop the unlikely double check. That won't
cause more idle pages, but reduce a lock contention.

This is also a preparation for later new page isolation feature.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/page_idle.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/mm/page_idle.c b/mm/page_idle.c
index 295512465065..914df63948b1 100644
--- a/mm/page_idle.c
+++ b/mm/page_idle.c
@@ -31,7 +31,6 @@
 static struct page *page_idle_get_page(unsigned long pfn)
 {
 	struct page *page;
-	pg_data_t *pgdat;
 
 	if (!pfn_valid(pfn))
 		return NULL;
@@ -41,13 +40,6 @@ static struct page *page_idle_get_page(unsigned long pfn)
 	    !get_page_unless_zero(page))
 		return NULL;
 
-	pgdat = page_pgdat(page);
-	spin_lock_irq(&pgdat->lru_lock);
-	if (unlikely(!PageLRU(page))) {
-		put_page(page);
-		page = NULL;
-	}
-	spin_unlock_irq(&pgdat->lru_lock);
 	return page;
 }
 
-- 
1.8.3.1

[PATCH v9 03/20] mm/page_idle: no unlikely double check for idle page counting

[Alex Shi]

As func comments mentioned, few isolated page missing be tolerated.
So why not do further to drop the unlikely double check. That won't
cause more idle pages, but reduce a lock contention.

This is also a preparation for later new page isolation feature.

Signed-off-by: Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
Cc: Matthew Wilcox <willy-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Cc: Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
---
 mm/page_idle.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/mm/page_idle.c b/mm/page_idle.c
index 295512465065..914df63948b1 100644
--- a/mm/page_idle.c
+++ b/mm/page_idle.c
@@ -31,7 +31,6 @@
 static struct page *page_idle_get_page(unsigned long pfn)
 {
 	struct page *page;
-	pg_data_t *pgdat;
 
 	if (!pfn_valid(pfn))
 		return NULL;
@@ -41,13 +40,6 @@ static struct page *page_idle_get_page(unsigned long pfn)
 	    !get_page_unless_zero(page))
 		return NULL;
 
-	pgdat = page_pgdat(page);
-	spin_lock_irq(&pgdat->lru_lock);
-	if (unlikely(!PageLRU(page))) {
-		put_page(page);
-		page = NULL;
-	}
-	spin_unlock_irq(&pgdat->lru_lock);
 	return page;
 }
 
-- 
1.8.3.1

[PATCH v9 04/20] mm/thp: move lru_add_page_tail func to huge_memory.c

[Alex Shi]

The func is only used in huge_memory.c, defining it in other file with a
CONFIG_TRANSPARENT_HUGEPAGE macro restrict just looks weird.

Let's move it close user.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
---
 include/linux/swap.h |  4 ++--
 mm/huge_memory.c     | 35 +++++++++++++++++++++++++++++++++++
 mm/swap.c            | 41 +----------------------------------------
 3 files changed, 38 insertions(+), 42 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 1e99f7ac1d7e..c555e8f161ad 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -328,11 +328,11 @@ struct vma_swap_readahead {
 
 
 /* linux/mm/swap.c */
+extern void update_page_reclaim_stat(struct lruvec *lruvec,
+						int file, int rotated);
 extern void lru_cache_add(struct page *);
 extern void lru_cache_add_anon(struct page *page);
 extern void lru_cache_add_file(struct page *page);
-extern void lru_add_page_tail(struct page *page, struct page *page_tail,
-			 struct lruvec *lruvec, struct list_head *head);
 extern void activate_page(struct page *);
 extern void mark_page_accessed(struct page *);
 extern void lru_add_drain(void);
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index b08b199f9a11..acef164a8981 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2445,6 +2445,41 @@ static void remap_page(struct page *page)
 	}
 }
 
+void lru_add_page_tail(struct page *page, struct page *page_tail,
+		       struct lruvec *lruvec, struct list_head *list)
+{
+	const int file = 0;
+
+	VM_BUG_ON_PAGE(!PageHead(page), page);
+	VM_BUG_ON_PAGE(PageCompound(page_tail), page);
+	VM_BUG_ON_PAGE(PageLRU(page_tail), page);
+	lockdep_assert_held(&lruvec_pgdat(lruvec)->lru_lock);
+
+	if (!list)
+		SetPageLRU(page_tail);
+
+	if (likely(PageLRU(page)))
+		list_add_tail(&page_tail->lru, &page->lru);
+	else if (list) {
+		/* page reclaim is reclaiming a huge page */
+		get_page(page_tail);
+		list_add_tail(&page_tail->lru, list);
+	} else {
+		/*
+		 * Head page has not yet been counted, as an hpage,
+		 * so we must account for each subpage individually.
+		 *
+		 * Put page_tail on the list at the correct position
+		 * so they all end up in order.
+		 */
+		add_page_to_lru_list_tail(page_tail, lruvec,
+					  page_lru(page_tail));
+	}
+
+	if (!PageUnevictable(page))
+		update_page_reclaim_stat(lruvec, file, PageActive(page_tail));
+}
+
 static void __split_huge_page_tail(struct page *head, int tail,
 		struct lruvec *lruvec, struct list_head *list)
 {
diff --git a/mm/swap.c b/mm/swap.c
index cf39d24ada2a..1ac24fc35d6b 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -262,8 +262,7 @@ void rotate_reclaimable_page(struct page *page)
 	}
 }
 
-static void update_page_reclaim_stat(struct lruvec *lruvec,
-				     int file, int rotated)
+void update_page_reclaim_stat(struct lruvec *lruvec, int file, int rotated)
 {
 	struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
 
@@ -885,44 +884,6 @@ void __pagevec_release(struct pagevec *pvec)
 }
 EXPORT_SYMBOL(__pagevec_release);
 
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-/* used by __split_huge_page_refcount() */
-void lru_add_page_tail(struct page *page, struct page *page_tail,
-		       struct lruvec *lruvec, struct list_head *list)
-{
-	const int file = 0;
-
-	VM_BUG_ON_PAGE(!PageHead(page), page);
-	VM_BUG_ON_PAGE(PageCompound(page_tail), page);
-	VM_BUG_ON_PAGE(PageLRU(page_tail), page);
-	lockdep_assert_held(&lruvec_pgdat(lruvec)->lru_lock);
-
-	if (!list)
-		SetPageLRU(page_tail);
-
-	if (likely(PageLRU(page)))
-		list_add_tail(&page_tail->lru, &page->lru);
-	else if (list) {
-		/* page reclaim is reclaiming a huge page */
-		get_page(page_tail);
-		list_add_tail(&page_tail->lru, list);
-	} else {
-		/*
-		 * Head page has not yet been counted, as an hpage,
-		 * so we must account for each subpage individually.
-		 *
-		 * Put page_tail on the list at the correct position
-		 * so they all end up in order.
-		 */
-		add_page_to_lru_list_tail(page_tail, lruvec,
-					  page_lru(page_tail));
-	}
-
-	if (!PageUnevictable(page))
-		update_page_reclaim_stat(lruvec, file, PageActive(page_tail));
-}
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
-
 static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec,
 				 void *arg)
 {
-- 
1.8.3.1

Re: [PATCH v9 04/20] mm/thp: move lru_add_page_tail func to huge_memory.c

[Kirill A. Shutemov]

On Mon, Mar 02, 2020 at 07:00:14PM +0800, Alex Shi wrote:
> The func is only used in huge_memory.c, defining it in other file with a
> CONFIG_TRANSPARENT_HUGEPAGE macro restrict just looks weird.
> 
> Let's move it close user.

I don't think it's strong enough justification. I would rather keep all
lru helpers in one place.

-- 
 Kirill A. Shutemov

Re: [PATCH v9 04/20] mm/thp: move lru_add_page_tail func to huge_memory.c

[Alex Shi]

在 2020/3/4 下午3:47, Kirill A. Shutemov 写道:
> On Mon, Mar 02, 2020 at 07:00:14PM +0800, Alex Shi wrote:
>> The func is only used in huge_memory.c, defining it in other file with a
>> CONFIG_TRANSPARENT_HUGEPAGE macro restrict just looks weird.
>>
>> Let's move it close user.
> 
> I don't think it's strong enough justification. I would rather keep all
> lru helpers in one place.
> 

Thanks for comments, Kirill,

If it's a common used func, yes.

But if you look into details of this func, it's thp used only func. 

Thanks
Alex

Re: [PATCH v9 04/20] mm/thp: move lru_add_page_tail func to huge_memory.c

[Alex Shi]

ÔÚ 2020/3/4 ÏÂÎç3:47, Kirill A. Shutemov дµÀ:
> On Mon, Mar 02, 2020 at 07:00:14PM +0800, Alex Shi wrote:
>> The func is only used in huge_memory.c, defining it in other file with a
>> CONFIG_TRANSPARENT_HUGEPAGE macro restrict just looks weird.
>>
>> Let's move it close user.
> 
> I don't think it's strong enough justification. I would rather keep all
> lru helpers in one place.
> 

Thanks for comments, Kirill,

If it's a common used func, yes.

But if you look into details of this func, it's thp used only func. 

Thanks
Alex

[PATCH v9 05/20] mm/thp: clean up lru_add_page_tail

[Alex Shi]

Since the first parameter is only used by head page, it's better to make
it stright. And no needs to keep head checking:
	VM_BUG_ON_PAGE(!PageHead(page), page);

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/huge_memory.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index acef164a8981..599367d25fca 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2445,21 +2445,20 @@ static void remap_page(struct page *page)
 	}
 }
 
-void lru_add_page_tail(struct page *page, struct page *page_tail,
+void lru_add_page_tail(struct page *head, struct page *page_tail,
 		       struct lruvec *lruvec, struct list_head *list)
 {
 	const int file = 0;
 
-	VM_BUG_ON_PAGE(!PageHead(page), page);
-	VM_BUG_ON_PAGE(PageCompound(page_tail), page);
-	VM_BUG_ON_PAGE(PageLRU(page_tail), page);
+	VM_BUG_ON_PAGE(PageCompound(page_tail), head);
+	VM_BUG_ON_PAGE(PageLRU(page_tail), head);
 	lockdep_assert_held(&lruvec_pgdat(lruvec)->lru_lock);
 
 	if (!list)
 		SetPageLRU(page_tail);
 
-	if (likely(PageLRU(page)))
-		list_add_tail(&page_tail->lru, &page->lru);
+	if (likely(PageLRU(head)))
+		list_add_tail(&page_tail->lru, &head->lru);
 	else if (list) {
 		/* page reclaim is reclaiming a huge page */
 		get_page(page_tail);
@@ -2476,7 +2475,7 @@ void lru_add_page_tail(struct page *page, struct page *page_tail,
 					  page_lru(page_tail));
 	}
 
-	if (!PageUnevictable(page))
+	if (!PageUnevictable(head))
 		update_page_reclaim_stat(lruvec, file, PageActive(page_tail));
 }
 
-- 
1.8.3.1

[PATCH v9 05/20] mm/thp: clean up lru_add_page_tail

[Alex Shi]

Since the first parameter is only used by head page, it's better to make
it stright. And no needs to keep head checking:
	VM_BUG_ON_PAGE(!PageHead(page), page);

Signed-off-by: Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
Cc: Matthew Wilcox <willy-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Cc: Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
---
 mm/huge_memory.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index acef164a8981..599367d25fca 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2445,21 +2445,20 @@ static void remap_page(struct page *page)
 	}
 }
 
-void lru_add_page_tail(struct page *page, struct page *page_tail,
+void lru_add_page_tail(struct page *head, struct page *page_tail,
 		       struct lruvec *lruvec, struct list_head *list)
 {
 	const int file = 0;
 
-	VM_BUG_ON_PAGE(!PageHead(page), page);
-	VM_BUG_ON_PAGE(PageCompound(page_tail), page);
-	VM_BUG_ON_PAGE(PageLRU(page_tail), page);
+	VM_BUG_ON_PAGE(PageCompound(page_tail), head);
+	VM_BUG_ON_PAGE(PageLRU(page_tail), head);
 	lockdep_assert_held(&lruvec_pgdat(lruvec)->lru_lock);
 
 	if (!list)
 		SetPageLRU(page_tail);
 
-	if (likely(PageLRU(page)))
-		list_add_tail(&page_tail->lru, &page->lru);
+	if (likely(PageLRU(head)))
+		list_add_tail(&page_tail->lru, &head->lru);
 	else if (list) {
 		/* page reclaim is reclaiming a huge page */
 		get_page(page_tail);
@@ -2476,7 +2475,7 @@ void lru_add_page_tail(struct page *page, struct page *page_tail,
 					  page_lru(page_tail));
 	}
 
-	if (!PageUnevictable(page))
+	if (!PageUnevictable(head))
 		update_page_reclaim_stat(lruvec, file, PageActive(page_tail));
 }
 
-- 
1.8.3.1

[PATCH v9 06/20] mm/thp: narrow lru locking

[Alex Shi]

Lru locking just guard the lru list and subpage's Mlocked. Including
other things can't give help just delay the locking release. So narrow
the locking for early lock release and better code meaning.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/huge_memory.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 599367d25fca..3835f87d03fd 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2542,13 +2542,14 @@ static void __split_huge_page_tail(struct page *head, int tail,
 }
 
 static void __split_huge_page(struct page *page, struct list_head *list,
-		pgoff_t end, unsigned long flags)
+				pgoff_t end)
 {
 	struct page *head = compound_head(page);
 	pg_data_t *pgdat = page_pgdat(head);
 	struct lruvec *lruvec;
 	struct address_space *swap_cache = NULL;
 	unsigned long offset = 0;
+	unsigned long flags;
 	int i;
 
 	lruvec = mem_cgroup_page_lruvec(head, pgdat);
@@ -2564,6 +2565,9 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 		xa_lock(&swap_cache->i_pages);
 	}
 
+	/* Lru list would be changed, don't care head's LRU bit. */
+	spin_lock_irqsave(&pgdat->lru_lock, flags);
+
 	for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
 		__split_huge_page_tail(head, i, lruvec, list);
 		/* Some pages can be beyond i_size: drop them from page cache */
@@ -2581,6 +2585,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 					head + i, 0);
 		}
 	}
+	spin_unlock_irqrestore(&pgdat->lru_lock, flags);
 
 	ClearPageCompound(head);
 
@@ -2601,8 +2606,6 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 		xa_unlock(&head->mapping->i_pages);
 	}
 
-	spin_unlock_irqrestore(&pgdat->lru_lock, flags);
-
 	remap_page(head);
 
 	for (i = 0; i < HPAGE_PMD_NR; i++) {
@@ -2740,13 +2743,11 @@ bool can_split_huge_page(struct page *page, int *pextra_pins)
 int split_huge_page_to_list(struct page *page, struct list_head *list)
 {
 	struct page *head = compound_head(page);
-	struct pglist_data *pgdata = NODE_DATA(page_to_nid(head));
 	struct deferred_split *ds_queue = get_deferred_split_queue(head);
 	struct anon_vma *anon_vma = NULL;
 	struct address_space *mapping = NULL;
 	int count, mapcount, extra_pins, ret;
 	bool mlocked;
-	unsigned long flags;
 	pgoff_t end;
 
 	VM_BUG_ON_PAGE(is_huge_zero_page(head), head);
@@ -2812,9 +2813,6 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 	if (mlocked)
 		lru_add_drain();
 
-	/* prevent PageLRU to go away from under us, and freeze lru stats */
-	spin_lock_irqsave(&pgdata->lru_lock, flags);
-
 	if (mapping) {
 		XA_STATE(xas, &mapping->i_pages, page_index(head));
 
@@ -2844,7 +2842,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 				__dec_node_page_state(head, NR_FILE_THPS);
 		}
 
-		__split_huge_page(page, list, end, flags);
+		__split_huge_page(page, list, end);
 		if (PageSwapCache(head)) {
 			swp_entry_t entry = { .val = page_private(head) };
 
@@ -2863,7 +2861,6 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 		spin_unlock(&ds_queue->split_queue_lock);
 fail:		if (mapping)
 			xa_unlock(&mapping->i_pages);
-		spin_unlock_irqrestore(&pgdata->lru_lock, flags);
 		remap_page(head);
 		ret = -EBUSY;
 	}
-- 
1.8.3.1

Re: [PATCH v9 06/20] mm/thp: narrow lru locking

[Kirill A. Shutemov]

On Mon, Mar 02, 2020 at 07:00:16PM +0800, Alex Shi wrote:
> @@ -2564,6 +2565,9 @@ static void __split_huge_page(struct page *page, struct list_head *list,
>  		xa_lock(&swap_cache->i_pages);
>  	}
>  
> +	/* Lru list would be changed, don't care head's LRU bit. */
> +	spin_lock_irqsave(&pgdat->lru_lock, flags);
> +
>  	for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
>  		__split_huge_page_tail(head, i, lruvec, list);
>  		/* Some pages can be beyond i_size: drop them from page cache */

You change locking order WRT i_pages lock. Is it safe?

-- 
 Kirill A. Shutemov

Re: [PATCH v9 06/20] mm/thp: narrow lru locking

[Kirill A. Shutemov]

On Mon, Mar 02, 2020 at 07:00:16PM +0800, Alex Shi wrote:
> @@ -2564,6 +2565,9 @@ static void __split_huge_page(struct page *page, struct list_head *list,
>  		xa_lock(&swap_cache->i_pages);
>  	}
>  
> +	/* Lru list would be changed, don't care head's LRU bit. */
> +	spin_lock_irqsave(&pgdat->lru_lock, flags);
> +
>  	for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
>  		__split_huge_page_tail(head, i, lruvec, list);
>  		/* Some pages can be beyond i_size: drop them from page cache */

You change locking order WRT i_pages lock. Is it safe?

-- 
 Kirill A. Shutemov

Re: [PATCH v9 06/20] mm/thp: narrow lru locking

[Alex Shi]

在 2020/3/4 下午4:02, Kirill A. Shutemov 写道:
> On Mon, Mar 02, 2020 at 07:00:16PM +0800, Alex Shi wrote:
>> @@ -2564,6 +2565,9 @@ static void __split_huge_page(struct page *page, struct list_head *list,
>>  		xa_lock(&swap_cache->i_pages);
>>  	}
>>  
>> +	/* Lru list would be changed, don't care head's LRU bit. */
>> +	spin_lock_irqsave(&pgdat->lru_lock, flags);
>> +
>>  	for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
>>  		__split_huge_page_tail(head, i, lruvec, list);
>>  		/* Some pages can be beyond i_size: drop them from page cache */
> 
> You change locking order WRT i_pages lock. Is it safe?
> 

Thanks Kirill,

I think so. and lock_dep/proving has no complain.

Any problem addressed?

Alex

Re: [PATCH v9 06/20] mm/thp: narrow lru locking

[Alex Shi]

ÔÚ 2020/3/4 ÏÂÎç4:02, Kirill A. Shutemov дµÀ:
> On Mon, Mar 02, 2020 at 07:00:16PM +0800, Alex Shi wrote:
>> @@ -2564,6 +2565,9 @@ static void __split_huge_page(struct page *page, struct list_head *list,
>>  		xa_lock(&swap_cache->i_pages);
>>  	}
>>  
>> +	/* Lru list would be changed, don't care head's LRU bit. */
>> +	spin_lock_irqsave(&pgdat->lru_lock, flags);
>> +
>>  	for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
>>  		__split_huge_page_tail(head, i, lruvec, list);
>>  		/* Some pages can be beyond i_size: drop them from page cache */
> 
> You change locking order WRT i_pages lock. Is it safe?
> 

Thanks Kirill,

I think so. and lock_dep/proving has no complain.

Any problem addressed?

Alex

[PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

[Alex Shi]

Combined PageLRU check and ClearPageLRU into one function by new
introduced func TestClearPageLRU. This function will be used as page
isolation precondition.

No functional change yet.

Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
---
 include/linux/page-flags.h |  1 +
 mm/memcontrol.c            |  4 ++--
 mm/mlock.c                 |  3 +--
 mm/swap.c                  |  8 ++------
 mm/vmscan.c                | 19 +++++++++----------
 5 files changed, 15 insertions(+), 20 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 1bf83c8fcaa7..5cb155f3191e 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -318,6 +318,7 @@ static inline void page_init_poison(struct page *page, size_t size)
 PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
 	__CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
 PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
+	TESTCLEARFLAG(LRU, lru, PF_HEAD)
 PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
 	TESTCLEARFLAG(Active, active, PF_HEAD)
 PAGEFLAG(Workingset, workingset, PF_HEAD)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 875e2aebcde7..f8419f3436a8 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2588,9 +2588,8 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
 		pgdat = page_pgdat(page);
 		spin_lock_irq(&pgdat->lru_lock);
 
-		if (PageLRU(page)) {
+		if (TestClearPageLRU(page)) {
 			lruvec = mem_cgroup_page_lruvec(page, pgdat);
-			ClearPageLRU(page);
 			del_page_from_lru_list(page, lruvec, page_lru(page));
 		} else
 			spin_unlock_irq(&pgdat->lru_lock);
@@ -2613,6 +2612,7 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
 
 	if (lrucare && lruvec) {
 		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+
 		VM_BUG_ON_PAGE(PageLRU(page), page);
 		SetPageLRU(page);
 		add_page_to_lru_list(page, lruvec, page_lru(page));
diff --git a/mm/mlock.c b/mm/mlock.c
index a72c1eeded77..03b3a5d99ad7 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -108,13 +108,12 @@ void mlock_vma_page(struct page *page)
  */
 static bool __munlock_isolate_lru_page(struct page *page, bool getpage)
 {
-	if (PageLRU(page)) {
+	if (TestClearPageLRU(page)) {
 		struct lruvec *lruvec;
 
 		lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
 		if (getpage)
 			get_page(page);
-		ClearPageLRU(page);
 		del_page_from_lru_list(page, lruvec, page_lru(page));
 		return true;
 	}
diff --git a/mm/swap.c b/mm/swap.c
index 1ac24fc35d6b..8e71bdd04a1a 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -59,15 +59,13 @@
  */
 static void __page_cache_release(struct page *page)
 {
-	if (PageLRU(page)) {
+	if (TestClearPageLRU(page)) {
 		pg_data_t *pgdat = page_pgdat(page);
 		struct lruvec *lruvec;
 		unsigned long flags;
 
 		spin_lock_irqsave(&pgdat->lru_lock, flags);
 		lruvec = mem_cgroup_page_lruvec(page, pgdat);
-		VM_BUG_ON_PAGE(!PageLRU(page), page);
-		__ClearPageLRU(page);
 		del_page_from_lru_list(page, lruvec, page_off_lru(page));
 		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
 	}
@@ -831,7 +829,7 @@ void release_pages(struct page **pages, int nr)
 			continue;
 		}
 
-		if (PageLRU(page)) {
+		if (TestClearPageLRU(page)) {
 			struct pglist_data *pgdat = page_pgdat(page);
 
 			if (pgdat != locked_pgdat) {
@@ -844,8 +842,6 @@ void release_pages(struct page **pages, int nr)
 			}
 
 			lruvec = mem_cgroup_page_lruvec(page, locked_pgdat);
-			VM_BUG_ON_PAGE(!PageLRU(page), page);
-			__ClearPageLRU(page);
 			del_page_from_lru_list(page, lruvec, page_off_lru(page));
 		}
 
diff --git a/mm/vmscan.c b/mm/vmscan.c
index dcdd33f65f43..8958454d50fe 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1751,21 +1751,20 @@ int isolate_lru_page(struct page *page)
 	VM_BUG_ON_PAGE(!page_count(page), page);
 	WARN_RATELIMIT(PageTail(page), "trying to isolate tail page");
 
-	if (PageLRU(page)) {
+	get_page(page);
+	if (TestClearPageLRU(page)) {
 		pg_data_t *pgdat = page_pgdat(page);
 		struct lruvec *lruvec;
+		int lru = page_lru(page);
 
-		spin_lock_irq(&pgdat->lru_lock);
 		lruvec = mem_cgroup_page_lruvec(page, pgdat);
-		if (PageLRU(page)) {
-			int lru = page_lru(page);
-			get_page(page);
-			ClearPageLRU(page);
-			del_page_from_lru_list(page, lruvec, lru);
-			ret = 0;
-		}
+		spin_lock_irq(&pgdat->lru_lock);
+		del_page_from_lru_list(page, lruvec, lru);
 		spin_unlock_irq(&pgdat->lru_lock);
-	}
+		ret = 0;
+	} else
+		put_page(page);
+
 	return ret;
 }
 
-- 
1.8.3.1

Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

[Andrew Morton]

On Mon,  2 Mar 2020 19:00:17 +0800 Alex Shi <alex.shi@linux.alibaba.com> wrote:

> Combined PageLRU check and ClearPageLRU into one function by new
> introduced func TestClearPageLRU. This function will be used as page
> isolation precondition.
> 
> No functional change yet.
> 
> ...
>
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2588,9 +2588,8 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
>  		pgdat = page_pgdat(page);
>  		spin_lock_irq(&pgdat->lru_lock);
>  
> -		if (PageLRU(page)) {
> +		if (TestClearPageLRU(page)) {
>  			lruvec = mem_cgroup_page_lruvec(page, pgdat);
> -			ClearPageLRU(page);
>  			del_page_from_lru_list(page, lruvec, page_lru(page));
>  		} else

The code will now get exclusive access of the page->flags cacheline and
will dirty that cacheline, even for !PageLRU() pages.  What is the
performance impact of this?

Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

[Alex Shi]

在 2020/3/3 上午6:11, Andrew Morton 写道:
>> -		if (PageLRU(page)) {
>> +		if (TestClearPageLRU(page)) {
>>  			lruvec = mem_cgroup_page_lruvec(page, pgdat);
>> -			ClearPageLRU(page);
>>  			del_page_from_lru_list(page, lruvec, page_lru(page));
>>  		} else
> 
> The code will now get exclusive access of the page->flags cacheline and
> will dirty that cacheline, even for !PageLRU() pages.  What is the
> performance impact of this?
> 

Hi Andrew,

Thanks a lot for comments!

I was tested the whole patchset with fengguang's case-lru-file-readtwice
https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/
which is most sensitive case on PageLRU I found. There are no clear performance
drop.

On this single patch, I just test the same case again, there is still no perf
drop. some data is here on my 96 threads machine:

		no lock_dep	w lock_dep and few other debug option
w this patch, 	50.96MB/s		32.93MB/s
w/o this patch, 50.50MB/s		33.53MB/s


And also no any warning from Intel 0day yet.

Thanks a lot!
Alex

Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

[Alex Shi]

ÔÚ 2020/3/3 ÉÏÎç6:11, Andrew Morton дµÀ:
>> -		if (PageLRU(page)) {
>> +		if (TestClearPageLRU(page)) {
>>  			lruvec = mem_cgroup_page_lruvec(page, pgdat);
>> -			ClearPageLRU(page);
>>  			del_page_from_lru_list(page, lruvec, page_lru(page));
>>  		} else
> 
> The code will now get exclusive access of the page->flags cacheline and
> will dirty that cacheline, even for !PageLRU() pages.  What is the
> performance impact of this?
> 

Hi Andrew,

Thanks a lot for comments!

I was tested the whole patchset with fengguang's case-lru-file-readtwice
https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/
which is most sensitive case on PageLRU I found. There are no clear performance
drop.

On this single patch, I just test the same case again, there is still no perf
drop. some data is here on my 96 threads machine:

		no lock_dep	w lock_dep and few other debug option
w this patch, 	50.96MB/s		32.93MB/s
w/o this patch, 50.50MB/s		33.53MB/s


And also no any warning from Intel 0day yet.

Thanks a lot!
Alex

Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

[Andrew Morton]

On Tue, 3 Mar 2020 12:11:34 +0800 Alex Shi <alex.shi@linux.alibaba.com> wrote:

> 
> 
> 在 2020/3/3 上午6:11, Andrew Morton 写道:
> >> -		if (PageLRU(page)) {
> >> +		if (TestClearPageLRU(page)) {
> >>  			lruvec = mem_cgroup_page_lruvec(page, pgdat);
> >> -			ClearPageLRU(page);
> >>  			del_page_from_lru_list(page, lruvec, page_lru(page));
> >>  		} else
> > 
> > The code will now get exclusive access of the page->flags cacheline and
> > will dirty that cacheline, even for !PageLRU() pages.  What is the
> > performance impact of this?
> > 
> 
> Hi Andrew,
> 
> Thanks a lot for comments!
> 
> I was tested the whole patchset with fengguang's case-lru-file-readtwice
> https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/
> which is most sensitive case on PageLRU I found. There are no clear performance
> drop.
> 
> On this single patch, I just test the same case again, there is still no perf
> drop. some data is here on my 96 threads machine:
> 
> 		no lock_dep	w lock_dep and few other debug option
> w this patch, 	50.96MB/s		32.93MB/s
> w/o this patch, 50.50MB/s		33.53MB/s
> 
> 

Well, any difference would be small and the numbers did get a bit
lower, albeit probably within the margin of error.

But you know, if someone were to send a patch which micro-optimized
some code by replacing 'TestClearXXX()' with `if PageXXX()
ClearPageXXX()', I would happily merge it!

Is this change essential to the overall patchset?  If not, I'd be
inclined to skip it?

Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

[Andrew Morton]

On Tue, 3 Mar 2020 12:11:34 +0800 Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org> wrote:

> 
> 
> 在 2020/3/3 上午6:11, Andrew Morton 写道:
> >> -		if (PageLRU(page)) {
> >> +		if (TestClearPageLRU(page)) {
> >>  			lruvec = mem_cgroup_page_lruvec(page, pgdat);
> >> -			ClearPageLRU(page);
> >>  			del_page_from_lru_list(page, lruvec, page_lru(page));
> >>  		} else
> > 
> > The code will now get exclusive access of the page->flags cacheline and
> > will dirty that cacheline, even for !PageLRU() pages.  What is the
> > performance impact of this?
> > 
> 
> Hi Andrew,
> 
> Thanks a lot for comments!
> 
> I was tested the whole patchset with fengguang's case-lru-file-readtwice
> https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/
> which is most sensitive case on PageLRU I found. There are no clear performance
> drop.
> 
> On this single patch, I just test the same case again, there is still no perf
> drop. some data is here on my 96 threads machine:
> 
> 		no lock_dep	w lock_dep and few other debug option
> w this patch, 	50.96MB/s		32.93MB/s
> w/o this patch, 50.50MB/s		33.53MB/s
> 
> 

Well, any difference would be small and the numbers did get a bit
lower, albeit probably within the margin of error.

But you know, if someone were to send a patch which micro-optimized
some code by replacing 'TestClearXXX()' with `if PageXXX()
ClearPageXXX()', I would happily merge it!

Is this change essential to the overall patchset?  If not, I'd be
inclined to skip it?

Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

[Alex Shi]

在 2020/3/4 上午8:46, Andrew Morton 写道:
> 
> Well, any difference would be small and the numbers did get a bit
> lower, albeit probably within the margin of error.
> 
> But you know, if someone were to send a patch which micro-optimized
> some code by replacing 'TestClearXXX()' with `if PageXXX()
> ClearPageXXX()', I would happily merge it!
> 
> Is this change essential to the overall patchset?  If not, I'd be
> inclined to skip it?
> 

Hi Andrew,

Thanks a lot for comments!
Yes, this patch is essential for all next.

Consider the normal memory testing would focus on user page, that probabably with PageLRU. 

Fengguang's vm-scalibicase-small-allocs which used a lots vm_area_struct slab, which may
got some impact. 0day/Cheng Rong is working on the test. In my roughly testing, it may drop 5% on my
96threads/394GB machine.

Thanks
Alex

Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

[Alex Shi]

在 2020/3/4 上午8:46, Andrew Morton 写道:
> 
> Well, any difference would be small and the numbers did get a bit
> lower, albeit probably within the margin of error.
> 
> But you know, if someone were to send a patch which micro-optimized
> some code by replacing 'TestClearXXX()' with `if PageXXX()
> ClearPageXXX()', I would happily merge it!
> 
> Is this change essential to the overall patchset?  If not, I'd be
> inclined to skip it?
> 

Hi Andrew,

Thanks a lot for comments!
Yes, this patch is essential for all next.

Consider the normal memory testing would focus on user page, that probabably with PageLRU. 

Fengguang's vm-scalibicase-small-allocs which used a lots vm_area_struct slab, which may
got some impact. 0day/Cheng Rong is working on the test. In my roughly testing, it may drop 5% on my
96threads/394GB machine.

Thanks
Alex

Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

[Rong Chen]

On Wed, Mar 04, 2020 at 03:06:48PM +0800, Alex Shi wrote:
> 
> 
> 在 2020/3/4 上午8:46, Andrew Morton 写道:
> > 
> > Well, any difference would be small and the numbers did get a bit
> > lower, albeit probably within the margin of error.
> > 
> > But you know, if someone were to send a patch which micro-optimized
> > some code by replacing 'TestClearXXX()' with `if PageXXX()
> > ClearPageXXX()', I would happily merge it!
> > 
> > Is this change essential to the overall patchset?  If not, I'd be
> > inclined to skip it?
> > 
> 
> Hi Andrew,
> 
> Thanks a lot for comments!
> Yes, this patch is essential for all next.
> 
> Consider the normal memory testing would focus on user page, that probabably with PageLRU. 
> 
> Fengguang's vm-scalibicase-small-allocs which used a lots vm_area_struct slab, which may
> got some impact. 0day/Cheng Rong is working on the test. In my roughly testing, it may drop 5% on my
> 96threads/394GB machine.
> 
> Thanks
> Alex

Hi,

We only tested one case and found a slight regression of vm-scalability.median from this patch set:

Test case: small allocs
=========================================================================================
compiler/cpufreq_governor/kconfig/rootfs/runtime/tbox_group/test/testcase/ucode:
  gcc-7/performance/x86_64-rhel-7.6/debian-x86_64-20191114.cgz/300s/lkp-ivb-d02/small-allocs/vm-scalability/0x21

commit: 
  v5.6-rc4
  f71ed0f653e9dbd57347f6321e36556004a17b52

        v5.6-rc4 f71ed0f653e9dbd57347f6321e3 
---------------- --------------------------- 
         %stddev     %change         %stddev
             \          |                \  
    998930            -1.4%     984729        vm-scalability.median

=========================================================================================
compiler/cpufreq_governor/kconfig/rootfs/runtime/tbox_group/test/testcase/ucode:
  gcc-7/performance/x86_64-rhel-7.6/debian-x86_64-20191114.cgz/300s/lkp-csl-2ap4/small-allocs/vm-scalability/0x500002c

commit: 
  v5.6-rc4
  f71ed0f653e9dbd57347f6321e36556004a17b52

        v5.6-rc4 f71ed0f653e9dbd57347f6321e3 
---------------- --------------------------- 
         %stddev     %change         %stddev
             \          |                \  
     64040            -2.2%      62641        vm-scalability.median
  12294118            -2.2%   12027483        vm-scalability.throughput
 3.695e+09            -2.2%  3.614e+09        vm-scalability.workload


$ git log --oneline v5.6-rc4..f71ed0f653e9dbd57347f6321e36556004a17b52
f71ed0f653e9d mm/memcg: add debug checking in lock_page_memcg
c56d782a737a5 mm/lru: add debug checking for page memcg moving
40f9438e4f7a9 mm/lru: revise the comments of lru_lock
cf4d433ab1f59 mm/pgdat: remove pgdat lru_lock
8b45216bf602c mm/swap: only change the lru_lock iff page's lruvec is different
9aeff27f856c4 mm/mlock: optimize munlock_pagevec by relocking
0fd16f50f4260 mm/lru: introduce the relock_page_lruvec function
e8bcc2440b133 mm/lru: replace pgdat lru_lock with lruvec lock
88013de2d9cfa mm/mlock: clean up __munlock_isolate_lru_page
037f0e01cc3a3 mm/memcg: move SetPageLRU out of lru_lock in commit_charge
5f889edacd91d mm/lru: take PageLRU first in moving page between lru lists
06998f054a82b mm/mlock: ClearPageLRU before get lru lock in munlock page isolation
5212e3636eed6 mm/lru: add page isolation precondition in __isolate_lru_page
a7b8b29f36b13 mm/lru: introduce TestClearPageLRU
f27e8da1e2fa1 mm/thp: narrow lru locking
2deca0177d843 mm/thp: clean up lru_add_page_tail
afbe030c47e06 mm/thp: move lru_add_page_tail func to huge_memory.c
9bee24913b538 mm/page_idle: no unlikely double check for idle page counting
40def76b96d7b mm/memcg: fold lock_page_lru into commit_charge
c1199696673c2 mm/vmscan: remove unnecessary lruvec adding

Best Regards,
Rong Chen

Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

[Rong Chen]

On Wed, Mar 04, 2020 at 03:06:48PM +0800, Alex Shi wrote:
> 
> 
> 在 2020/3/4 上午8:46, Andrew Morton 写道:
> > 
> > Well, any difference would be small and the numbers did get a bit
> > lower, albeit probably within the margin of error.
> > 
> > But you know, if someone were to send a patch which micro-optimized
> > some code by replacing 'TestClearXXX()' with `if PageXXX()
> > ClearPageXXX()', I would happily merge it!
> > 
> > Is this change essential to the overall patchset?  If not, I'd be
> > inclined to skip it?
> > 
> 
> Hi Andrew,
> 
> Thanks a lot for comments!
> Yes, this patch is essential for all next.
> 
> Consider the normal memory testing would focus on user page, that probabably with PageLRU. 
> 
> Fengguang's vm-scalibicase-small-allocs which used a lots vm_area_struct slab, which may
> got some impact. 0day/Cheng Rong is working on the test. In my roughly testing, it may drop 5% on my
> 96threads/394GB machine.
> 
> Thanks
> Alex

Hi,

We only tested one case and found a slight regression of vm-scalability.median from this patch set:

Test case: small allocs
=========================================================================================
compiler/cpufreq_governor/kconfig/rootfs/runtime/tbox_group/test/testcase/ucode:
  gcc-7/performance/x86_64-rhel-7.6/debian-x86_64-20191114.cgz/300s/lkp-ivb-d02/small-allocs/vm-scalability/0x21

commit: 
  v5.6-rc4
  f71ed0f653e9dbd57347f6321e36556004a17b52

        v5.6-rc4 f71ed0f653e9dbd57347f6321e3 
---------------- --------------------------- 
         %stddev     %change         %stddev
             \          |                \  
    998930            -1.4%     984729        vm-scalability.median

=========================================================================================
compiler/cpufreq_governor/kconfig/rootfs/runtime/tbox_group/test/testcase/ucode:
  gcc-7/performance/x86_64-rhel-7.6/debian-x86_64-20191114.cgz/300s/lkp-csl-2ap4/small-allocs/vm-scalability/0x500002c

commit: 
  v5.6-rc4
  f71ed0f653e9dbd57347f6321e36556004a17b52

        v5.6-rc4 f71ed0f653e9dbd57347f6321e3 
---------------- --------------------------- 
         %stddev     %change         %stddev
             \          |                \  
     64040            -2.2%      62641        vm-scalability.median
  12294118            -2.2%   12027483        vm-scalability.throughput
 3.695e+09            -2.2%  3.614e+09        vm-scalability.workload


$ git log --oneline v5.6-rc4..f71ed0f653e9dbd57347f6321e36556004a17b52
f71ed0f653e9d mm/memcg: add debug checking in lock_page_memcg
c56d782a737a5 mm/lru: add debug checking for page memcg moving
40f9438e4f7a9 mm/lru: revise the comments of lru_lock
cf4d433ab1f59 mm/pgdat: remove pgdat lru_lock
8b45216bf602c mm/swap: only change the lru_lock iff page's lruvec is different
9aeff27f856c4 mm/mlock: optimize munlock_pagevec by relocking
0fd16f50f4260 mm/lru: introduce the relock_page_lruvec function
e8bcc2440b133 mm/lru: replace pgdat lru_lock with lruvec lock
88013de2d9cfa mm/mlock: clean up __munlock_isolate_lru_page
037f0e01cc3a3 mm/memcg: move SetPageLRU out of lru_lock in commit_charge
5f889edacd91d mm/lru: take PageLRU first in moving page between lru lists
06998f054a82b mm/mlock: ClearPageLRU before get lru lock in munlock page isolation
5212e3636eed6 mm/lru: add page isolation precondition in __isolate_lru_page
a7b8b29f36b13 mm/lru: introduce TestClearPageLRU
f27e8da1e2fa1 mm/thp: narrow lru locking
2deca0177d843 mm/thp: clean up lru_add_page_tail
afbe030c47e06 mm/thp: move lru_add_page_tail func to huge_memory.c
9bee24913b538 mm/page_idle: no unlikely double check for idle page counting
40def76b96d7b mm/memcg: fold lock_page_lru into commit_charge
c1199696673c2 mm/vmscan: remove unnecessary lruvec adding

Best Regards,
Rong Chen

Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

[Alex Shi]

在 2020/3/4 下午5:03, Rong Chen 写道:
>> Hi Andrew,
>>
>> Thanks a lot for comments!
>> Yes, this patch is essential for all next.
>>
>> Consider the normal memory testing would focus on user page, that probabably with PageLRU. 
>>
>> Fengguang's vm-scalibicase-small-allocs which used a lots vm_area_struct slab, which may
>> got some impact. 0day/Cheng Rong is working on the test. In my roughly testing, it may drop 5% on my
>> 96threads/394GB machine.
>>
>> Thanks
>> Alex
> Hi,
> 
> We only tested one case and found a slight regression of vm-scalability.median from this patch set:
> 
> Test case: small allocs
> =========================================================================================
> compiler/cpufreq_governor/kconfig/rootfs/runtime/tbox_group/test/testcase/ucode:
>   gcc-7/performance/x86_64-rhel-7.6/debian-x86_64-20191114.cgz/300s/lkp-ivb-d02/small-allocs/vm-scalability/0x21

It's a very acceptable result!

Thanks a lot for so quick testing! I believe your results would be far more stable than me. :)

(My testing show quit different result in 2 reboot(1.3% or 6.6% drop). Maybe sth wrong for me in this case.)

Thanks for your report!
Alex

Re: [PATCH v9 07/20] mm/lru: introduce TestClearPageLRU

[Alex Shi]

在 2020/3/4 下午5:03, Rong Chen 写道:
>> Hi Andrew,
>>
>> Thanks a lot for comments!
>> Yes, this patch is essential for all next.
>>
>> Consider the normal memory testing would focus on user page, that probabably with PageLRU. 
>>
>> Fengguang's vm-scalibicase-small-allocs which used a lots vm_area_struct slab, which may
>> got some impact. 0day/Cheng Rong is working on the test. In my roughly testing, it may drop 5% on my
>> 96threads/394GB machine.
>>
>> Thanks
>> Alex
> Hi,
> 
> We only tested one case and found a slight regression of vm-scalability.median from this patch set:
> 
> Test case: small allocs
> =========================================================================================
> compiler/cpufreq_governor/kconfig/rootfs/runtime/tbox_group/test/testcase/ucode:
>   gcc-7/performance/x86_64-rhel-7.6/debian-x86_64-20191114.cgz/300s/lkp-ivb-d02/small-allocs/vm-scalability/0x21

It's a very acceptable result!

Thanks a lot for so quick testing! I believe your results would be far more stable than me. :)

(My testing show quit different result in 2 reboot(1.3% or 6.6% drop). Maybe sth wrong for me in this case.)

Thanks for your report!
Alex

[PATCH v9 08/20] mm/lru: add page isolation precondition in __isolate_lru_page

[Alex Shi]

Johannes Weiner has suggested:
"
So here is a crazy idea that may be worth exploring:

Right now, pgdat->lru_lock protects both PageLRU *and* the lruvec's
linked list.

Can we make PageLRU atomic and use it to stabilize the lru_lock
instead, and then use the lru_lock only serialize list operations?
...
"

Yes, this patch is doing so on  __isolate_lru_page which is the core
page isolation func in compaction and shrinking path.

This patch move clear page lru action before compaction getting lru_lock,
makes it as a necessary condition for page isolation. Hence, PageLRU may
be cleared druing shrink_inactive_list path for isolation reason. If so,
we can skip that page's in reclaim.

It's a preparation for later per memcg lru_lock change.

Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
---
 include/linux/swap.h |  2 +-
 mm/compaction.c      | 25 +++++++++++++++++--------
 mm/vmscan.c          | 48 ++++++++++++++++++++++++++----------------------
 3 files changed, 44 insertions(+), 31 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index c555e8f161ad..69f0794f1da3 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -351,7 +351,7 @@ extern void lru_cache_add_active_or_unevictable(struct page *page,
 extern unsigned long zone_reclaimable_pages(struct zone *zone);
 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 					gfp_t gfp_mask, nodemask_t *mask);
-extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
+extern int __isolate_lru_page_prepare(struct page *page, isolate_mode_t mode);
 extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
 						  unsigned long nr_pages,
 						  gfp_t gfp_mask,
diff --git a/mm/compaction.c b/mm/compaction.c
index 672d3c78c6ab..1baba328d089 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -948,6 +948,23 @@ static bool too_many_isolated(pg_data_t *pgdat)
 		if (!(cc->gfp_mask & __GFP_FS) && page_mapping(page))
 			goto isolate_fail;
 
+		if (__isolate_lru_page_prepare(page, isolate_mode) != 0)
+			goto isolate_fail;
+
+		/*
+		 * Be careful not to clear PageLRU until after we're
+		 * sure the page is not being freed elsewhere -- the
+		 * page release code relies on it.
+		 */
+		if (unlikely(!get_page_unless_zero(page)))
+			goto isolate_fail;
+
+		/* Try isolate the page */
+		if (!TestClearPageLRU(page)) {
+			put_page(page);
+			goto isolate_fail;
+		}
+
 		/* If we already hold the lock, we can skip some rechecking */
 		if (!locked) {
 			locked = compact_lock_irqsave(&pgdat->lru_lock,
@@ -960,10 +977,6 @@ static bool too_many_isolated(pg_data_t *pgdat)
 					goto isolate_abort;
 			}
 
-			/* Recheck PageLRU and PageCompound under lock */
-			if (!PageLRU(page))
-				goto isolate_fail;
-
 			/*
 			 * Page become compound since the non-locked check,
 			 * and it's on LRU. It can only be a THP so the order
@@ -977,10 +990,6 @@ static bool too_many_isolated(pg_data_t *pgdat)
 
 		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
-		/* Try isolate the page */
-		if (__isolate_lru_page(page, isolate_mode) != 0)
-			goto isolate_fail;
-
 		VM_BUG_ON_PAGE(PageCompound(page), page);
 
 		/* Successfully isolated */
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8958454d50fe..bc2ec3fe4f48 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1522,20 +1522,20 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
  *
  * returns 0 on success, -ve errno on failure.
  */
-int __isolate_lru_page(struct page *page, isolate_mode_t mode)
+int __isolate_lru_page_prepare(struct page *page, isolate_mode_t mode)
 {
 	int ret = -EINVAL;
 
-	/* Only take pages on the LRU. */
-	if (!PageLRU(page))
-		return ret;
-
 	/* Compaction should not handle unevictable pages but CMA can do so */
 	if (PageUnevictable(page) && !(mode & ISOLATE_UNEVICTABLE))
 		return ret;
 
 	ret = -EBUSY;
 
+	/* Only take pages on the LRU. */
+	if (!PageLRU(page))
+		return ret;
+
 	/*
 	 * To minimise LRU disruption, the caller can indicate that it only
 	 * wants to isolate pages it will be able to operate on without
@@ -1576,20 +1576,9 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode)
 	if ((mode & ISOLATE_UNMAPPED) && page_mapped(page))
 		return ret;
 
-	if (likely(get_page_unless_zero(page))) {
-		/*
-		 * Be careful not to clear PageLRU until after we're
-		 * sure the page is not being freed elsewhere -- the
-		 * page release code relies on it.
-		 */
-		ClearPageLRU(page);
-		ret = 0;
-	}
-
-	return ret;
+	return 0;
 }
 
-
 /*
  * Update LRU sizes after isolating pages. The LRU size updates must
  * be complete before mem_cgroup_update_lru_size due to a santity check.
@@ -1653,8 +1642,6 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 		page = lru_to_page(src);
 		prefetchw_prev_lru_page(page, src, flags);
 
-		VM_BUG_ON_PAGE(!PageLRU(page), page);
-
 		nr_pages = compound_nr(page);
 		total_scan += nr_pages;
 
@@ -1675,17 +1662,34 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 		 * only when the page is being freed somewhere else.
 		 */
 		scan += nr_pages;
-		switch (__isolate_lru_page(page, mode)) {
+		switch (__isolate_lru_page_prepare(page, mode)) {
 		case 0:
+			/*
+			 * Be careful not to clear PageLRU until after we're
+			 * sure the page is not being freed elsewhere -- the
+			 * page release code relies on it.
+			 */
+			if (unlikely(!get_page_unless_zero(page)))
+				goto busy;
+
+			if (!TestClearPageLRU(page)) {
+				/*
+				 * This page may in other isolation path,
+				 * but we still hold lru_lock.
+				 */
+				put_page(page);
+				goto busy;
+			}
+
 			nr_taken += nr_pages;
 			nr_zone_taken[page_zonenum(page)] += nr_pages;
 			list_move(&page->lru, dst);
 			break;
-
+busy:
 		case -EBUSY:
 			/* else it is being freed elsewhere */
 			list_move(&page->lru, src);
-			continue;
+			break;
 
 		default:
 			BUG();
-- 
1.8.3.1

[PATCH v9 09/20] mm/mlock: ClearPageLRU before get lru lock in munlock page isolation

[Alex Shi]

This is one of effort to split the PageLRU clear from old page
isolation.

This patch move the lru_lock after TestClearPageLRU, which takes holding
PageLRU as precondition for page isolation, as a preparation for later
lru_lock replacment. So we have to unfold __munlock_isolate_lru_page.

__split_huge_page_refcount doesn't exist, but we still have to guard
PageMlocked in __split_huge_page_tail. That make code ugly.
Anyway we still remove 2 gotos.

[lkp@intel.com: found a sleeping function bug ... at mm/rmap.c:1861]
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/mlock.c | 35 +++++++++++++++++++++++------------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c
index 03b3a5d99ad7..7ddc52ca14b1 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -181,6 +181,7 @@ static void __munlock_isolation_failed(struct page *page)
 unsigned int munlock_vma_page(struct page *page)
 {
 	int nr_pages;
+	bool clearlru = false;
 	pg_data_t *pgdat = page_pgdat(page);
 
 	/* For try_to_munlock() and to serialize with page migration */
@@ -189,32 +190,42 @@ unsigned int munlock_vma_page(struct page *page)
 	VM_BUG_ON_PAGE(PageTail(page), page);
 
 	/*
-	 * Serialize with any parallel __split_huge_page_refcount() which
+	 * Serialize with any parallel __split_huge_page_tail() which
 	 * might otherwise copy PageMlocked to part of the tail pages before
 	 * we clear it in the head page. It also stabilizes hpage_nr_pages().
 	 */
+	get_page(page);
+	clearlru = TestClearPageLRU(page);
 	spin_lock_irq(&pgdat->lru_lock);
 
 	if (!TestClearPageMlocked(page)) {
-		/* Potentially, PTE-mapped THP: do not skip the rest PTEs */
-		nr_pages = 1;
-		goto unlock_out;
+		if (clearlru)
+			SetPageLRU(page);
+		/*
+		 * Potentially, PTE-mapped THP: do not skip the rest PTEs
+		 * Reuse lock as memory barrier for release_pages racing.
+		 */
+		spin_unlock_irq(&pgdat->lru_lock);
+		put_page(page);
+		return 0;
 	}
 
 	nr_pages = hpage_nr_pages(page);
 	__mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
 
-	if (__munlock_isolate_lru_page(page, true)) {
+	if (clearlru) {
+		struct lruvec *lruvec;
+
+		lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+		del_page_from_lru_list(page, lruvec, page_lru(page));
 		spin_unlock_irq(&pgdat->lru_lock);
 		__munlock_isolated_page(page);
-		goto out;
+	} else {
+		spin_unlock_irq(&pgdat->lru_lock);
+		put_page(page);
+		__munlock_isolation_failed(page);
 	}
-	__munlock_isolation_failed(page);
-
-unlock_out:
-	spin_unlock_irq(&pgdat->lru_lock);
 
-out:
 	return nr_pages - 1;
 }
 
@@ -323,8 +334,8 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 		pagevec_add(&pvec_putback, pvec->pages[i]);
 		pvec->pages[i] = NULL;
 	}
-	__mod_zone_page_state(zone, NR_MLOCK, delta_munlocked);
 	spin_unlock_irq(&zone->zone_pgdat->lru_lock);
+	__mod_zone_page_state(zone, NR_MLOCK, delta_munlocked);
 
 	/* Now we can release pins of pages that we are not munlocking */
 	pagevec_release(&pvec_putback);
-- 
1.8.3.1

[PATCH v9 09/20] mm/mlock: ClearPageLRU before get lru lock in munlock page isolation

[Alex Shi]

This is one of effort to split the PageLRU clear from old page
isolation.

This patch move the lru_lock after TestClearPageLRU, which takes holding
PageLRU as precondition for page isolation, as a preparation for later
lru_lock replacment. So we have to unfold __munlock_isolate_lru_page.

__split_huge_page_refcount doesn't exist, but we still have to guard
PageMlocked in __split_huge_page_tail. That make code ugly.
Anyway we still remove 2 gotos.

[lkp-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org: found a sleeping function bug ... at mm/rmap.c:1861]
Signed-off-by: Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
Cc: Kirill A. Shutemov <kirill-oKw7cIdHH8eLwutG50LtGA@public.gmane.org>
Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
Cc: Matthew Wilcox <willy-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Cc: Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
---
 mm/mlock.c | 35 +++++++++++++++++++++++------------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c
index 03b3a5d99ad7..7ddc52ca14b1 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -181,6 +181,7 @@ static void __munlock_isolation_failed(struct page *page)
 unsigned int munlock_vma_page(struct page *page)
 {
 	int nr_pages;
+	bool clearlru = false;
 	pg_data_t *pgdat = page_pgdat(page);
 
 	/* For try_to_munlock() and to serialize with page migration */
@@ -189,32 +190,42 @@ unsigned int munlock_vma_page(struct page *page)
 	VM_BUG_ON_PAGE(PageTail(page), page);
 
 	/*
-	 * Serialize with any parallel __split_huge_page_refcount() which
+	 * Serialize with any parallel __split_huge_page_tail() which
 	 * might otherwise copy PageMlocked to part of the tail pages before
 	 * we clear it in the head page. It also stabilizes hpage_nr_pages().
 	 */
+	get_page(page);
+	clearlru = TestClearPageLRU(page);
 	spin_lock_irq(&pgdat->lru_lock);
 
 	if (!TestClearPageMlocked(page)) {
-		/* Potentially, PTE-mapped THP: do not skip the rest PTEs */
-		nr_pages = 1;
-		goto unlock_out;
+		if (clearlru)
+			SetPageLRU(page);
+		/*
+		 * Potentially, PTE-mapped THP: do not skip the rest PTEs
+		 * Reuse lock as memory barrier for release_pages racing.
+		 */
+		spin_unlock_irq(&pgdat->lru_lock);
+		put_page(page);
+		return 0;
 	}
 
 	nr_pages = hpage_nr_pages(page);
 	__mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
 
-	if (__munlock_isolate_lru_page(page, true)) {
+	if (clearlru) {
+		struct lruvec *lruvec;
+
+		lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+		del_page_from_lru_list(page, lruvec, page_lru(page));
 		spin_unlock_irq(&pgdat->lru_lock);
 		__munlock_isolated_page(page);
-		goto out;
+	} else {
+		spin_unlock_irq(&pgdat->lru_lock);
+		put_page(page);
+		__munlock_isolation_failed(page);
 	}
-	__munlock_isolation_failed(page);
-
-unlock_out:
-	spin_unlock_irq(&pgdat->lru_lock);
 
-out:
 	return nr_pages - 1;
 }
 
@@ -323,8 +334,8 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 		pagevec_add(&pvec_putback, pvec->pages[i]);
 		pvec->pages[i] = NULL;
 	}
-	__mod_zone_page_state(zone, NR_MLOCK, delta_munlocked);
 	spin_unlock_irq(&zone->zone_pgdat->lru_lock);
+	__mod_zone_page_state(zone, NR_MLOCK, delta_munlocked);
 
 	/* Now we can release pins of pages that we are not munlocking */
 	pagevec_release(&pvec_putback);
-- 
1.8.3.1

[PATCH v9 10/20] mm/lru: take PageLRU first in moving page between lru lists

[Alex Shi]

Current move_fn do moving with PageLRU in lru_lock protection. Moving
include a lru isolation and a lru adding. As to the isolation part,
we need take PageLRU before move_fn, that add a extra PageLRU guard
to block other isolations. and set lru bit back after page settled on
lru list.

This makes TestClearPageLRU as isolation's necessary condition in
page moving between lru lists.

Another page moving between lru lists is check_move_unevictable_pages
func, we need to take PageLRu temporarilly same as move_fn.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/swap.c   | 42 ++++++++++++++++++++++++------------------
 mm/vmscan.c |  3 ++-
 2 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index 8e71bdd04a1a..16af7c8369fe 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -187,7 +187,7 @@ int get_kernel_page(unsigned long start, int write, struct page **pages)
 
 static void pagevec_lru_move_fn(struct pagevec *pvec,
 	void (*move_fn)(struct page *page, struct lruvec *lruvec, void *arg),
-	void *arg)
+	void *arg, bool isolation)
 {
 	int i;
 	struct pglist_data *pgdat = NULL;
@@ -198,6 +198,10 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 		struct page *page = pvec->pages[i];
 		struct pglist_data *pagepgdat = page_pgdat(page);
 
+		if (isolation && !TestClearPageLRU(page))
+			continue;
+
+		/* every page should be isolated from lru */
 		if (pagepgdat != pgdat) {
 			if (pgdat)
 				spin_unlock_irqrestore(&pgdat->lru_lock, flags);
@@ -207,6 +211,9 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 
 		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 		(*move_fn)(page, lruvec, arg);
+
+		if (isolation)
+			SetPageLRU(page);
 	}
 	if (pgdat)
 		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
@@ -219,7 +226,7 @@ static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec,
 {
 	int *pgmoved = arg;
 
-	if (PageLRU(page) && !PageUnevictable(page)) {
+	if (!PageUnevictable(page)) {
 		del_page_from_lru_list(page, lruvec, page_lru(page));
 		ClearPageActive(page);
 		add_page_to_lru_list_tail(page, lruvec, page_lru(page));
@@ -235,7 +242,7 @@ static void pagevec_move_tail(struct pagevec *pvec)
 {
 	int pgmoved = 0;
 
-	pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, &pgmoved);
+	pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, &pgmoved, true);
 	__count_vm_events(PGROTATED, pgmoved);
 }
 
@@ -272,7 +279,7 @@ void update_page_reclaim_stat(struct lruvec *lruvec, int file, int rotated)
 static void __activate_page(struct page *page, struct lruvec *lruvec,
 			    void *arg)
 {
-	if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
+	if (!PageActive(page) && !PageUnevictable(page)) {
 		int file = page_is_file_cache(page);
 		int lru = page_lru_base_type(page);
 
@@ -293,7 +300,7 @@ static void activate_page_drain(int cpu)
 	struct pagevec *pvec = &per_cpu(activate_page_pvecs, cpu);
 
 	if (pagevec_count(pvec))
-		pagevec_lru_move_fn(pvec, __activate_page, NULL);
+		pagevec_lru_move_fn(pvec, __activate_page, NULL, true);
 }
 
 static bool need_activate_page_drain(int cpu)
@@ -309,7 +316,7 @@ void activate_page(struct page *page)
 
 		get_page(page);
 		if (!pagevec_add(pvec, page) || PageCompound(page))
-			pagevec_lru_move_fn(pvec, __activate_page, NULL);
+			pagevec_lru_move_fn(pvec, __activate_page, NULL, true);
 		put_cpu_var(activate_page_pvecs);
 	}
 }
@@ -501,9 +508,6 @@ static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec,
 	int lru, file;
 	bool active;
 
-	if (!PageLRU(page))
-		return;
-
 	if (PageUnevictable(page))
 		return;
 
@@ -544,7 +548,7 @@ static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec,
 static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec,
 			    void *arg)
 {
-	if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) {
+	if (PageActive(page) && !PageUnevictable(page)) {
 		int file = page_is_file_cache(page);
 		int lru = page_lru_base_type(page);
 
@@ -561,7 +565,7 @@ static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec,
 static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec,
 			    void *arg)
 {
-	if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
+	if (PageAnon(page) && PageSwapBacked(page) &&
 	    !PageSwapCache(page) && !PageUnevictable(page)) {
 		bool active = PageActive(page);
 
@@ -607,15 +611,15 @@ void lru_add_drain_cpu(int cpu)
 
 	pvec = &per_cpu(lru_deactivate_file_pvecs, cpu);
 	if (pagevec_count(pvec))
-		pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, NULL);
+		pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, NULL, true);
 
 	pvec = &per_cpu(lru_deactivate_pvecs, cpu);
 	if (pagevec_count(pvec))
-		pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
+		pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL, true);
 
 	pvec = &per_cpu(lru_lazyfree_pvecs, cpu);
 	if (pagevec_count(pvec))
-		pagevec_lru_move_fn(pvec, lru_lazyfree_fn, NULL);
+		pagevec_lru_move_fn(pvec, lru_lazyfree_fn, NULL, true);
 
 	activate_page_drain(cpu);
 }
@@ -641,7 +645,8 @@ void deactivate_file_page(struct page *page)
 		struct pagevec *pvec = &get_cpu_var(lru_deactivate_file_pvecs);
 
 		if (!pagevec_add(pvec, page) || PageCompound(page))
-			pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, NULL);
+			pagevec_lru_move_fn(pvec,
+					lru_deactivate_file_fn, NULL, true);
 		put_cpu_var(lru_deactivate_file_pvecs);
 	}
 }
@@ -661,7 +666,8 @@ void deactivate_page(struct page *page)
 
 		get_page(page);
 		if (!pagevec_add(pvec, page) || PageCompound(page))
-			pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
+			pagevec_lru_move_fn(pvec,
+					lru_deactivate_fn, NULL, true);
 		put_cpu_var(lru_deactivate_pvecs);
 	}
 }
@@ -681,7 +687,7 @@ void mark_page_lazyfree(struct page *page)
 
 		get_page(page);
 		if (!pagevec_add(pvec, page) || PageCompound(page))
-			pagevec_lru_move_fn(pvec, lru_lazyfree_fn, NULL);
+			pagevec_lru_move_fn(pvec, lru_lazyfree_fn, NULL, true);
 		put_cpu_var(lru_lazyfree_pvecs);
 	}
 }
@@ -941,7 +947,7 @@ static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec,
  */
 void __pagevec_lru_add(struct pagevec *pvec)
 {
-	pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn, NULL);
+	pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn, NULL, false);
 }
 EXPORT_SYMBOL(__pagevec_lru_add);
 
diff --git a/mm/vmscan.c b/mm/vmscan.c
index bc2ec3fe4f48..efaa4f41044e 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4343,7 +4343,7 @@ void check_move_unevictable_pages(struct pagevec *pvec)
 		}
 		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
-		if (!PageLRU(page) || !PageUnevictable(page))
+		if (!TestClearPageLRU(page) || !PageUnevictable(page))
 			continue;
 
 		if (page_evictable(page)) {
@@ -4354,6 +4354,7 @@ void check_move_unevictable_pages(struct pagevec *pvec)
 			del_page_from_lru_list(page, lruvec, LRU_UNEVICTABLE);
 			add_page_to_lru_list(page, lruvec, lru);
 			pgrescued++;
+			SetPageLRU(page);
 		}
 	}
 
-- 
1.8.3.1

[PATCH v9 11/20] mm/memcg: move SetPageLRU out of lru_lock in commit_charge

[Alex Shi]

Since lru lock doesn't defense PageLRU anymore, move the setting out of
lock may save a bit lock contention time.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/memcontrol.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f8419f3436a8..7d7b861a948c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2614,9 +2614,9 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
 		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
 		VM_BUG_ON_PAGE(PageLRU(page), page);
-		SetPageLRU(page);
 		add_page_to_lru_list(page, lruvec, page_lru(page));
 		spin_unlock_irq(&pgdat->lru_lock);
+		SetPageLRU(page);
 	}
 }
 
-- 
1.8.3.1

[PATCH v9 11/20] mm/memcg: move SetPageLRU out of lru_lock in commit_charge

[Alex Shi]

Since lru lock doesn't defense PageLRU anymore, move the setting out of
lock may save a bit lock contention time.

Signed-off-by: Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
Cc: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
Cc: Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Vladimir Davydov <vdavydov.dev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
---
 mm/memcontrol.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f8419f3436a8..7d7b861a948c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2614,9 +2614,9 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
 		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
 		VM_BUG_ON_PAGE(PageLRU(page), page);
-		SetPageLRU(page);
 		add_page_to_lru_list(page, lruvec, page_lru(page));
 		spin_unlock_irq(&pgdat->lru_lock);
+		SetPageLRU(page);
 	}
 }
 
-- 
1.8.3.1

[PATCH v9 12/20] mm/mlock: clean up __munlock_isolate_lru_page

[Alex Shi]

clean up __munlock_isolate_lru_page func for later lru lock change.
No functional change.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/mlock.c | 47 ++++++++++++++++++-----------------------------
 1 file changed, 18 insertions(+), 29 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c
index 7ddc52ca14b1..a43b3da78541 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -103,25 +103,6 @@ void mlock_vma_page(struct page *page)
 }
 
 /*
- * Isolate a page from LRU with optional get_page() pin.
- * Assumes lru_lock already held and page already pinned.
- */
-static bool __munlock_isolate_lru_page(struct page *page, bool getpage)
-{
-	if (TestClearPageLRU(page)) {
-		struct lruvec *lruvec;
-
-		lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
-		if (getpage)
-			get_page(page);
-		del_page_from_lru_list(page, lruvec, page_lru(page));
-		return true;
-	}
-
-	return false;
-}
-
-/*
  * Finish munlock after successful page isolation
  *
  * Page must be locked. This is a wrapper for try_to_munlock()
@@ -311,26 +292,34 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 	spin_lock_irq(&zone->zone_pgdat->lru_lock);
 	for (i = 0; i < nr; i++) {
 		struct page *page = pvec->pages[i];
+		struct lruvec *lruvec;
 
-		if (TestClearPageMlocked(page)) {
-			/*
-			 * We already have pin from follow_page_mask()
-			 * so we can spare the get_page() here.
-			 */
-			if (__munlock_isolate_lru_page(page, false))
-				continue;
-			else
-				__munlock_isolation_failed(page);
-		} else {
+		if (!TestClearPageMlocked(page)) {
 			delta_munlocked++;
+			goto putback;
+		}
+
+		if (!TestClearPageLRU(page)) {
+			__munlock_isolation_failed(page);
+			goto putback;
 		}
 
 		/*
+		 * Isolate this page.
+		 * We already have pin from follow_page_mask()
+		 * so we can spare the get_page() here.
+		 */
+		lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+		del_page_from_lru_list(page, lruvec, page_lru(page));
+		continue;
+
+		/*
 		 * We won't be munlocking this page in the next phase
 		 * but we still need to release the follow_page_mask()
 		 * pin. We cannot do it under lru_lock however. If it's
 		 * the last pin, __page_cache_release() would deadlock.
 		 */
+putback:
 		pagevec_add(&pvec_putback, pvec->pages[i]);
 		pvec->pages[i] = NULL;
 	}
-- 
1.8.3.1

[PATCH v9 13/20] mm/lru: replace pgdat lru_lock with lruvec lock

[Alex Shi]

This patch moves lru_lock into lruvec, give a lru_lock for each of
lruvec, thus bring a lru_lock for each of memcg per node. So on a large
node machine, each of memcg don't need suffer from per node pgdat->lru_lock
waiting. They could go fast with their self lru_lock.

We introduces function lock_page_lruvec, which will lock the page's
memcg's lruvec->lru_lock. (Thanks Johannes Weiner, Hugh Dickins and
Konstantin Khlebnikov suggestion/reminder during patch writting.)

This is the key patch to replace per node lru_lock with per memcg
lruvec lock, with few palce full back more frequency lru locking.
But the later patch will use relock_page_lruvec_xxx to fill up the gap.

According to Daniel Jordan's suggestion, I run 208 'dd' with on 104
containers on a 2s * 26cores * HT box with a modefied case:
  https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/tree/case-lru-file-readtwice

With this and later patches, the readtwice performance increases about
80% within concurrent containers.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: cgroups@vger.kernel.org
---
 include/linux/memcontrol.h | 35 ++++++++++++++++++++++
 include/linux/mmzone.h     |  2 ++
 mm/compaction.c            | 51 ++++++++++++++++++++------------
 mm/huge_memory.c           |  9 ++----
 mm/memcontrol.c            | 50 +++++++++++++++++++++++++-------
 mm/mlock.c                 | 18 +++++-------
 mm/mmzone.c                |  1 +
 mm/swap.c                  | 72 +++++++++++++++++-----------------------------
 mm/vmscan.c                | 57 ++++++++++++++++--------------------
 9 files changed, 170 insertions(+), 125 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index a7a0a1a5c8d5..b8a04f0a2ab8 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -424,6 +424,13 @@ static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg,
 
 struct mem_cgroup *get_mem_cgroup_from_page(struct page *page);
 
+struct lruvec *lock_page_lruvec_irq(struct page *page);
+struct lruvec *lock_page_lruvec_irqsave(struct page *page,
+						unsigned long *flags);
+
+void unlock_page_lruvec_irq(struct lruvec *lruvec);
+void unlock_page_lruvec_irqrestore(struct lruvec *lruvec, unsigned long flags);
+
 static inline
 struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css){
 	return css ? container_of(css, struct mem_cgroup, css) : NULL;
@@ -926,6 +933,34 @@ static inline void mem_cgroup_put(struct mem_cgroup *memcg)
 {
 }
 
+static inline struct lruvec *lock_page_lruvec_irq(struct page *page)
+{
+	struct pglist_data *pgdat = page_pgdat(page);
+
+	spin_lock_irq(&pgdat->__lruvec.lru_lock);
+	return &pgdat->__lruvec;
+}
+
+static inline struct lruvec *lock_page_lruvec_irqsave(struct page *page,
+		unsigned long *flagsp)
+{
+	struct pglist_data *pgdat = page_pgdat(page);
+
+	spin_lock_irqsave(&pgdat->__lruvec.lru_lock, *flagsp);
+	return &pgdat->__lruvec;
+}
+
+static inline void unlock_page_lruvec_irq(struct lruvec *lruvec)
+{
+	spin_unlock_irq(&lruvec->lru_lock);
+}
+
+static inline void unlock_page_lruvec_irqrestore(struct lruvec *lruvec,
+		unsigned long flags)
+{
+	spin_unlock_irqrestore(&lruvec->lru_lock, flags);
+}
+
 static inline struct mem_cgroup *
 mem_cgroup_iter(struct mem_cgroup *root,
 		struct mem_cgroup *prev,
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 462f6873905a..a7bdff94990d 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -308,6 +308,8 @@ struct lruvec {
 	atomic_long_t			inactive_age;
 	/* Refaults at the time of last reclaim cycle */
 	unsigned long			refaults;
+	/* per lruvec lru_lock for memcg */
+	spinlock_t			lru_lock;
 	/* Various lruvec state flags (enum lruvec_flags) */
 	unsigned long			flags;
 #ifdef CONFIG_MEMCG
diff --git a/mm/compaction.c b/mm/compaction.c
index 1baba328d089..4a773f0ffedf 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -786,7 +786,7 @@ static bool too_many_isolated(pg_data_t *pgdat)
 	unsigned long nr_scanned = 0, nr_isolated = 0;
 	struct lruvec *lruvec;
 	unsigned long flags = 0;
-	bool locked = false;
+	struct lruvec *locked_lruvec = NULL;
 	struct page *page = NULL, *valid_page = NULL;
 	unsigned long start_pfn = low_pfn;
 	bool skip_on_failure = false;
@@ -846,11 +846,20 @@ static bool too_many_isolated(pg_data_t *pgdat)
 		 * contention, to give chance to IRQs. Abort completely if
 		 * a fatal signal is pending.
 		 */
-		if (!(low_pfn % SWAP_CLUSTER_MAX)
-		    && compact_unlock_should_abort(&pgdat->lru_lock,
-					    flags, &locked, cc)) {
-			low_pfn = 0;
-			goto fatal_pending;
+		if (!(low_pfn % SWAP_CLUSTER_MAX)) {
+			if (locked_lruvec) {
+				unlock_page_lruvec_irqrestore(locked_lruvec, flags);
+				locked_lruvec = NULL;
+			}
+
+			if (fatal_signal_pending(current)) {
+				cc->contended = true;
+
+				low_pfn = 0;
+				goto fatal_pending;
+			}
+
+			cond_resched();
 		}
 
 		if (!pfn_valid_within(low_pfn))
@@ -919,10 +928,9 @@ static bool too_many_isolated(pg_data_t *pgdat)
 			 */
 			if (unlikely(__PageMovable(page)) &&
 					!PageIsolated(page)) {
-				if (locked) {
-					spin_unlock_irqrestore(&pgdat->lru_lock,
-									flags);
-					locked = false;
+				if (locked_lruvec) {
+					unlock_page_lruvec_irqrestore(locked_lruvec, flags);
+					locked_lruvec = NULL;
 				}
 
 				if (!isolate_movable_page(page, isolate_mode))
@@ -965,10 +973,16 @@ static bool too_many_isolated(pg_data_t *pgdat)
 			goto isolate_fail;
 		}
 
+		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+
 		/* If we already hold the lock, we can skip some rechecking */
-		if (!locked) {
-			locked = compact_lock_irqsave(&pgdat->lru_lock,
-								&flags, cc);
+		if (lruvec != locked_lruvec) {
+			if (locked_lruvec) {
+				unlock_page_lruvec_irqrestore(locked_lruvec, flags);
+				locked_lruvec = NULL;
+			}
+			compact_lock_irqsave(&lruvec->lru_lock, &flags, cc);
+			locked_lruvec = lruvec;
 
 			/* Try get exclusive access under lock */
 			if (!skip_updated) {
@@ -988,7 +1002,6 @@ static bool too_many_isolated(pg_data_t *pgdat)
 			}
 		}
 
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
 		VM_BUG_ON_PAGE(PageCompound(page), page);
 
@@ -1025,9 +1038,9 @@ static bool too_many_isolated(pg_data_t *pgdat)
 		 * page anyway.
 		 */
 		if (nr_isolated) {
-			if (locked) {
-				spin_unlock_irqrestore(&pgdat->lru_lock, flags);
-				locked = false;
+			if (locked_lruvec) {
+				unlock_page_lruvec_irqrestore(locked_lruvec, flags);
+				locked_lruvec = NULL;
 			}
 			putback_movable_pages(&cc->migratepages);
 			cc->nr_migratepages = 0;
@@ -1052,8 +1065,8 @@ static bool too_many_isolated(pg_data_t *pgdat)
 		low_pfn = end_pfn;
 
 isolate_abort:
-	if (locked)
-		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+	if (locked_lruvec)
+		unlock_page_lruvec_irqrestore(locked_lruvec, flags);
 
 	/*
 	 * Updated the cached scanner pfn once the pageblock has been scanned
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 3835f87d03fd..7af56d0fb044 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2452,7 +2452,7 @@ void lru_add_page_tail(struct page *head, struct page *page_tail,
 
 	VM_BUG_ON_PAGE(PageCompound(page_tail), head);
 	VM_BUG_ON_PAGE(PageLRU(page_tail), head);
-	lockdep_assert_held(&lruvec_pgdat(lruvec)->lru_lock);
+	lockdep_assert_held(&lruvec->lru_lock);
 
 	if (!list)
 		SetPageLRU(page_tail);
@@ -2545,15 +2545,12 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 				pgoff_t end)
 {
 	struct page *head = compound_head(page);
-	pg_data_t *pgdat = page_pgdat(head);
 	struct lruvec *lruvec;
 	struct address_space *swap_cache = NULL;
 	unsigned long offset = 0;
 	unsigned long flags;
 	int i;
 
-	lruvec = mem_cgroup_page_lruvec(head, pgdat);
-
 	/* complete memcg works before add pages to LRU */
 	mem_cgroup_split_huge_fixup(head);
 
@@ -2566,7 +2563,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 	}
 
 	/* Lru list would be changed, don't care head's LRU bit. */
-	spin_lock_irqsave(&pgdat->lru_lock, flags);
+	lruvec = lock_page_lruvec_irqsave(head, &flags);
 
 	for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
 		__split_huge_page_tail(head, i, lruvec, list);
@@ -2585,7 +2582,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 					head + i, 0);
 		}
 	}
-	spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+	unlock_page_lruvec_irqrestore(lruvec, flags);
 
 	ClearPageCompound(head);
 
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7d7b861a948c..b0c156da60fe 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1219,7 +1219,7 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd
 		goto out;
 	}
 
-	memcg = page->mem_cgroup;
+	memcg = READ_ONCE(page->mem_cgroup);
 	/*
 	 * Swapcache readahead pages are added to the LRU - and
 	 * possibly migrated - before they are charged.
@@ -1240,6 +1240,37 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd
 	return lruvec;
 }
 
+/* page must be isolated */
+struct lruvec *lock_page_lruvec_irq(struct page *page)
+{
+	struct lruvec *lruvec;
+
+	lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+	spin_lock_irq(&lruvec->lru_lock);
+
+	return lruvec;
+}
+
+struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags)
+{
+	struct lruvec *lruvec;
+
+	lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+	spin_lock_irqsave(&lruvec->lru_lock, *flags);
+
+	return lruvec;
+}
+
+void unlock_page_lruvec_irq(struct lruvec *lruvec)
+{
+	spin_unlock_irq(&lruvec->lru_lock);
+}
+
+void unlock_page_lruvec_irqrestore(struct lruvec *lruvec, unsigned long flags)
+{
+	spin_unlock_irqrestore(&lruvec->lru_lock, flags);
+}
+
 /**
  * mem_cgroup_update_lru_size - account for adding or removing an lru page
  * @lruvec: mem_cgroup per zone lru vector
@@ -2576,7 +2607,6 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
 			  bool lrucare)
 {
 	struct lruvec *lruvec = NULL;
-	pg_data_t *pgdat;
 
 	VM_BUG_ON_PAGE(page->mem_cgroup, page);
 
@@ -2585,14 +2615,12 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
 	 * may already be on some other mem_cgroup's LRU.  Take care of it.
 	 */
 	if (lrucare) {
-		pgdat = page_pgdat(page);
-		spin_lock_irq(&pgdat->lru_lock);
-
 		if (TestClearPageLRU(page)) {
-			lruvec = mem_cgroup_page_lruvec(page, pgdat);
+			lruvec = lock_page_lruvec_irq(page);
+
 			del_page_from_lru_list(page, lruvec, page_lru(page));
-		} else
-			spin_unlock_irq(&pgdat->lru_lock);
+			unlock_page_lruvec_irq(lruvec);
+		}
 	}
 	/*
 	 * Nobody should be changing or seriously looking at
@@ -2611,11 +2639,11 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
 	page->mem_cgroup = memcg;
 
 	if (lrucare && lruvec) {
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+		lruvec = lock_page_lruvec_irq(page);
 
 		VM_BUG_ON_PAGE(PageLRU(page), page);
 		add_page_to_lru_list(page, lruvec, page_lru(page));
-		spin_unlock_irq(&pgdat->lru_lock);
+		unlock_page_lruvec_irq(lruvec);
 		SetPageLRU(page);
 	}
 }
@@ -2913,7 +2941,7 @@ void __memcg_kmem_uncharge(struct page *page, int order)
 
 /*
  * Because tail pages are not marked as "used", set it. We're under
- * pgdat->lru_lock and migration entries setup in all page mappings.
+ * lruvec->lru_lock and migration entries setup in all page mappings.
  */
 void mem_cgroup_split_huge_fixup(struct page *head)
 {
diff --git a/mm/mlock.c b/mm/mlock.c
index a43b3da78541..d285348b147e 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -163,7 +163,7 @@ unsigned int munlock_vma_page(struct page *page)
 {
 	int nr_pages;
 	bool clearlru = false;
-	pg_data_t *pgdat = page_pgdat(page);
+	struct lruvec *lruvec;
 
 	/* For try_to_munlock() and to serialize with page migration */
 	BUG_ON(!PageLocked(page));
@@ -177,7 +177,7 @@ unsigned int munlock_vma_page(struct page *page)
 	 */
 	get_page(page);
 	clearlru = TestClearPageLRU(page);
-	spin_lock_irq(&pgdat->lru_lock);
+	lruvec = lock_page_lruvec_irq(page);
 
 	if (!TestClearPageMlocked(page)) {
 		if (clearlru)
@@ -186,7 +186,7 @@ unsigned int munlock_vma_page(struct page *page)
 		 * Potentially, PTE-mapped THP: do not skip the rest PTEs
 		 * Reuse lock as memory barrier for release_pages racing.
 		 */
-		spin_unlock_irq(&pgdat->lru_lock);
+		unlock_page_lruvec_irq(lruvec);
 		put_page(page);
 		return 0;
 	}
@@ -195,14 +195,11 @@ unsigned int munlock_vma_page(struct page *page)
 	__mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
 
 	if (clearlru) {
-		struct lruvec *lruvec;
-
-		lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
 		del_page_from_lru_list(page, lruvec, page_lru(page));
-		spin_unlock_irq(&pgdat->lru_lock);
+		unlock_page_lruvec_irq(lruvec);
 		__munlock_isolated_page(page);
 	} else {
-		spin_unlock_irq(&pgdat->lru_lock);
+		unlock_page_lruvec_irq(lruvec);
 		put_page(page);
 		__munlock_isolation_failed(page);
 	}
@@ -289,7 +286,6 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 	pagevec_init(&pvec_putback);
 
 	/* Phase 1: page isolation */
-	spin_lock_irq(&zone->zone_pgdat->lru_lock);
 	for (i = 0; i < nr; i++) {
 		struct page *page = pvec->pages[i];
 		struct lruvec *lruvec;
@@ -309,8 +305,9 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 		 * We already have pin from follow_page_mask()
 		 * so we can spare the get_page() here.
 		 */
-		lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+		lruvec = lock_page_lruvec_irq(page);
 		del_page_from_lru_list(page, lruvec, page_lru(page));
+		unlock_page_lruvec_irq(lruvec);
 		continue;
 
 		/*
@@ -323,7 +320,6 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 		pagevec_add(&pvec_putback, pvec->pages[i]);
 		pvec->pages[i] = NULL;
 	}
-	spin_unlock_irq(&zone->zone_pgdat->lru_lock);
 	__mod_zone_page_state(zone, NR_MLOCK, delta_munlocked);
 
 	/* Now we can release pins of pages that we are not munlocking */
diff --git a/mm/mmzone.c b/mm/mmzone.c
index 4686fdc23bb9..3750a90ed4a0 100644
--- a/mm/mmzone.c
+++ b/mm/mmzone.c
@@ -91,6 +91,7 @@ void lruvec_init(struct lruvec *lruvec)
 	enum lru_list lru;
 
 	memset(lruvec, 0, sizeof(struct lruvec));
+	spin_lock_init(&lruvec->lru_lock);
 
 	for_each_lru(lru)
 		INIT_LIST_HEAD(&lruvec->lists[lru]);
diff --git a/mm/swap.c b/mm/swap.c
index 16af7c8369fe..50c856246f84 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -60,14 +60,12 @@
 static void __page_cache_release(struct page *page)
 {
 	if (TestClearPageLRU(page)) {
-		pg_data_t *pgdat = page_pgdat(page);
 		struct lruvec *lruvec;
 		unsigned long flags;
 
-		spin_lock_irqsave(&pgdat->lru_lock, flags);
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+		lruvec = lock_page_lruvec_irqsave(page, &flags);
 		del_page_from_lru_list(page, lruvec, page_off_lru(page));
-		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+		unlock_page_lruvec_irqrestore(lruvec, flags);
 	}
 	__ClearPageWaiters(page);
 }
@@ -190,33 +188,22 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 	void *arg, bool isolation)
 {
 	int i;
-	struct pglist_data *pgdat = NULL;
-	struct lruvec *lruvec;
+	struct lruvec *lruvec = NULL;
 	unsigned long flags = 0;
 
 	for (i = 0; i < pagevec_count(pvec); i++) {
 		struct page *page = pvec->pages[i];
-		struct pglist_data *pagepgdat = page_pgdat(page);
 
 		if (isolation && !TestClearPageLRU(page))
 			continue;
 
-		/* every page should be isolated from lru */
-		if (pagepgdat != pgdat) {
-			if (pgdat)
-				spin_unlock_irqrestore(&pgdat->lru_lock, flags);
-			pgdat = pagepgdat;
-			spin_lock_irqsave(&pgdat->lru_lock, flags);
-		}
-
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+		lruvec = lock_page_lruvec_irqsave(page, &flags);
 		(*move_fn)(page, lruvec, arg);
+		unlock_page_lruvec_irqrestore(lruvec, flags);
 
 		if (isolation)
 			SetPageLRU(page);
 	}
-	if (pgdat)
-		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
 	release_pages(pvec->pages, pvec->nr);
 	pagevec_reinit(pvec);
 }
@@ -328,12 +315,12 @@ static inline void activate_page_drain(int cpu)
 
 void activate_page(struct page *page)
 {
-	pg_data_t *pgdat = page_pgdat(page);
+	struct lruvec *lruvec;
 
 	page = compound_head(page);
-	spin_lock_irq(&pgdat->lru_lock);
-	__activate_page(page, mem_cgroup_page_lruvec(page, pgdat), NULL);
-	spin_unlock_irq(&pgdat->lru_lock);
+	lruvec = lock_page_lruvec_irq(page);
+	__activate_page(page, lruvec, NULL);
+	unlock_page_lruvec_irq(lruvec);
 }
 #endif
 
@@ -783,8 +770,7 @@ void release_pages(struct page **pages, int nr)
 {
 	int i;
 	LIST_HEAD(pages_to_free);
-	struct pglist_data *locked_pgdat = NULL;
-	struct lruvec *lruvec;
+	struct lruvec *lruvec = NULL;
 	unsigned long uninitialized_var(flags);
 	unsigned int uninitialized_var(lock_batch);
 
@@ -794,21 +780,20 @@ void release_pages(struct page **pages, int nr)
 		/*
 		 * Make sure the IRQ-safe lock-holding time does not get
 		 * excessive with a continuous string of pages from the
-		 * same pgdat. The lock is held only if pgdat != NULL.
+		 * same lruvec. The lock is held only if lruvec != NULL.
 		 */
-		if (locked_pgdat && ++lock_batch == SWAP_CLUSTER_MAX) {
-			spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags);
-			locked_pgdat = NULL;
+		if (lruvec && ++lock_batch == SWAP_CLUSTER_MAX) {
+			unlock_page_lruvec_irqrestore(lruvec, flags);
+			lruvec = NULL;
 		}
 
 		if (is_huge_zero_page(page))
 			continue;
 
 		if (is_zone_device_page(page)) {
-			if (locked_pgdat) {
-				spin_unlock_irqrestore(&locked_pgdat->lru_lock,
-						       flags);
-				locked_pgdat = NULL;
+			if (lruvec) {
+				unlock_page_lruvec_irqrestore(lruvec, flags);
+				lruvec = NULL;
 			}
 			/*
 			 * ZONE_DEVICE pages that return 'false' from
@@ -827,27 +812,24 @@ void release_pages(struct page **pages, int nr)
 			continue;
 
 		if (PageCompound(page)) {
-			if (locked_pgdat) {
-				spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags);
-				locked_pgdat = NULL;
+			if (lruvec) {
+				unlock_page_lruvec_irqrestore(lruvec, flags);
+				lruvec = NULL;
 			}
 			__put_compound_page(page);
 			continue;
 		}
 
 		if (TestClearPageLRU(page)) {
-			struct pglist_data *pgdat = page_pgdat(page);
+			struct lruvec *new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
 
-			if (pgdat != locked_pgdat) {
-				if (locked_pgdat)
-					spin_unlock_irqrestore(&locked_pgdat->lru_lock,
-									flags);
+			if (new_lruvec != lruvec) {
+				if (lruvec)
+					unlock_page_lruvec_irqrestore(lruvec, flags);
 				lock_batch = 0;
-				locked_pgdat = pgdat;
-				spin_lock_irqsave(&locked_pgdat->lru_lock, flags);
+				lruvec = lock_page_lruvec_irqsave(page, &flags);
 			}
 
-			lruvec = mem_cgroup_page_lruvec(page, locked_pgdat);
 			del_page_from_lru_list(page, lruvec, page_off_lru(page));
 		}
 
@@ -857,8 +839,8 @@ void release_pages(struct page **pages, int nr)
 
 		list_add(&page->lru, &pages_to_free);
 	}
-	if (locked_pgdat)
-		spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags);
+	if (lruvec)
+		unlock_page_lruvec_irqrestore(lruvec, flags);
 
 	mem_cgroup_uncharge_list(&pages_to_free);
 	free_unref_page_list(&pages_to_free);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index efaa4f41044e..a58cd5ee9ea1 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1757,14 +1757,12 @@ int isolate_lru_page(struct page *page)
 
 	get_page(page);
 	if (TestClearPageLRU(page)) {
-		pg_data_t *pgdat = page_pgdat(page);
 		struct lruvec *lruvec;
 		int lru = page_lru(page);
 
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
-		spin_lock_irq(&pgdat->lru_lock);
+		lruvec = lock_page_lruvec_irq(page);
 		del_page_from_lru_list(page, lruvec, lru);
-		spin_unlock_irq(&pgdat->lru_lock);
+		unlock_page_lruvec_irq(lruvec);
 		ret = 0;
 	} else
 		put_page(page);
@@ -1832,7 +1830,6 @@ static int too_many_isolated(struct pglist_data *pgdat, int file,
 static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 						     struct list_head *list)
 {
-	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
 	int nr_pages, nr_moved = 0;
 	LIST_HEAD(pages_to_free);
 	struct page *page;
@@ -1843,9 +1840,9 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 		VM_BUG_ON_PAGE(PageLRU(page), page);
 		list_del(&page->lru);
 		if (unlikely(!page_evictable(page))) {
-			spin_unlock_irq(&pgdat->lru_lock);
+			spin_unlock_irq(&lruvec->lru_lock);
 			putback_lru_page(page);
-			spin_lock_irq(&pgdat->lru_lock);
+			spin_lock_irq(&lruvec->lru_lock);
 			continue;
 		}
 
@@ -1866,18 +1863,16 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 			__ClearPageActive(page);
 
 			if (unlikely(PageCompound(page))) {
-				spin_unlock_irq(&pgdat->lru_lock);
+				spin_unlock_irq(&lruvec->lru_lock);
 				(*get_compound_page_dtor(page))(page);
-				spin_lock_irq(&pgdat->lru_lock);
+				spin_lock_irq(&lruvec->lru_lock);
 			} else
 				list_add(&page->lru, &pages_to_free);
 			continue;
 		}
 
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 		lru = page_lru(page);
 		nr_pages = hpage_nr_pages(page);
-
 		update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
 		list_add(&page->lru, &lruvec->lists[lru]);
 		nr_moved += nr_pages;
@@ -1938,7 +1933,7 @@ static int current_may_throttle(void)
 
 	lru_add_drain();
 
-	spin_lock_irq(&pgdat->lru_lock);
+	spin_lock_irq(&lruvec->lru_lock);
 
 	nr_taken = isolate_lru_pages(nr_to_scan, lruvec, &page_list,
 				     &nr_scanned, sc, lru);
@@ -1950,7 +1945,7 @@ static int current_may_throttle(void)
 	if (!cgroup_reclaim(sc))
 		__count_vm_events(item, nr_scanned);
 	__count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned);
-	spin_unlock_irq(&pgdat->lru_lock);
+	spin_unlock_irq(&lruvec->lru_lock);
 
 	if (nr_taken == 0)
 		return 0;
@@ -1958,7 +1953,7 @@ static int current_may_throttle(void)
 	nr_reclaimed = shrink_page_list(&page_list, pgdat, sc, 0,
 				&stat, false);
 
-	spin_lock_irq(&pgdat->lru_lock);
+	spin_lock_irq(&lruvec->lru_lock);
 
 	item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT;
 	if (!cgroup_reclaim(sc))
@@ -1971,7 +1966,7 @@ static int current_may_throttle(void)
 
 	__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
 
-	spin_unlock_irq(&pgdat->lru_lock);
+	spin_unlock_irq(&lruvec->lru_lock);
 
 	mem_cgroup_uncharge_list(&page_list);
 	free_unref_page_list(&page_list);
@@ -2024,7 +2019,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 
 	lru_add_drain();
 
-	spin_lock_irq(&pgdat->lru_lock);
+	spin_lock_irq(&lruvec->lru_lock);
 
 	nr_taken = isolate_lru_pages(nr_to_scan, lruvec, &l_hold,
 				     &nr_scanned, sc, lru);
@@ -2035,7 +2030,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 	__count_vm_events(PGREFILL, nr_scanned);
 	__count_memcg_events(lruvec_memcg(lruvec), PGREFILL, nr_scanned);
 
-	spin_unlock_irq(&pgdat->lru_lock);
+	spin_unlock_irq(&lruvec->lru_lock);
 
 	while (!list_empty(&l_hold)) {
 		cond_resched();
@@ -2081,7 +2076,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 	/*
 	 * Move pages back to the lru list.
 	 */
-	spin_lock_irq(&pgdat->lru_lock);
+	spin_lock_irq(&lruvec->lru_lock);
 	/*
 	 * Count referenced pages from currently used mappings as rotated,
 	 * even though only some of them are actually re-activated.  This
@@ -2099,7 +2094,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 	__count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate);
 
 	__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
-	spin_unlock_irq(&pgdat->lru_lock);
+	spin_unlock_irq(&lruvec->lru_lock);
 
 	mem_cgroup_uncharge_list(&l_active);
 	free_unref_page_list(&l_active);
@@ -2248,7 +2243,6 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
 	struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
 	u64 fraction[2];
 	u64 denominator = 0;	/* gcc */
-	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
 	unsigned long anon_prio, file_prio;
 	enum scan_balance scan_balance;
 	unsigned long anon, file;
@@ -2326,7 +2320,7 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
 	file  = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE, MAX_NR_ZONES) +
 		lruvec_lru_size(lruvec, LRU_INACTIVE_FILE, MAX_NR_ZONES);
 
-	spin_lock_irq(&pgdat->lru_lock);
+	spin_lock_irq(&lruvec->lru_lock);
 	if (unlikely(reclaim_stat->recent_scanned[0] > anon / 4)) {
 		reclaim_stat->recent_scanned[0] /= 2;
 		reclaim_stat->recent_rotated[0] /= 2;
@@ -2347,7 +2341,7 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
 
 	fp = file_prio * (reclaim_stat->recent_scanned[1] + 1);
 	fp /= reclaim_stat->recent_rotated[1] + 1;
-	spin_unlock_irq(&pgdat->lru_lock);
+	spin_unlock_irq(&lruvec->lru_lock);
 
 	fraction[0] = ap;
 	fraction[1] = fp;
@@ -4324,24 +4318,21 @@ int page_evictable(struct page *page)
  */
 void check_move_unevictable_pages(struct pagevec *pvec)
 {
-	struct lruvec *lruvec;
-	struct pglist_data *pgdat = NULL;
+	struct lruvec *lruvec = NULL;
 	int pgscanned = 0;
 	int pgrescued = 0;
 	int i;
 
 	for (i = 0; i < pvec->nr; i++) {
 		struct page *page = pvec->pages[i];
-		struct pglist_data *pagepgdat = page_pgdat(page);
+		struct lruvec *new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
 
 		pgscanned++;
-		if (pagepgdat != pgdat) {
-			if (pgdat)
-				spin_unlock_irq(&pgdat->lru_lock);
-			pgdat = pagepgdat;
-			spin_lock_irq(&pgdat->lru_lock);
+		if (lruvec != new_lruvec) {
+			if (lruvec)
+				unlock_page_lruvec_irq(lruvec);
+			lruvec = lock_page_lruvec_irq(page);
 		}
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
 		if (!TestClearPageLRU(page) || !PageUnevictable(page))
 			continue;
@@ -4358,10 +4349,10 @@ void check_move_unevictable_pages(struct pagevec *pvec)
 		}
 	}
 
-	if (pgdat) {
+	if (lruvec) {
 		__count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued);
 		__count_vm_events(UNEVICTABLE_PGSCANNED, pgscanned);
-		spin_unlock_irq(&pgdat->lru_lock);
+		unlock_page_lruvec_irq(lruvec);
 	}
 }
 EXPORT_SYMBOL_GPL(check_move_unevictable_pages);
-- 
1.8.3.1

[PATCH v9 13/20] mm/lru: replace pgdat lru_lock with lruvec lock

[Alex Shi]

This patch moves lru_lock into lruvec, give a lru_lock for each of
lruvec, thus bring a lru_lock for each of memcg per node. So on a large
node machine, each of memcg don't need suffer from per node pgdat->lru_lock
waiting. They could go fast with their self lru_lock.

We introduces function lock_page_lruvec, which will lock the page's
memcg's lruvec->lru_lock. (Thanks Johannes Weiner, Hugh Dickins and
Konstantin Khlebnikov suggestion/reminder during patch writting.)

This is the key patch to replace per node lru_lock with per memcg
lruvec lock, with few palce full back more frequency lru locking.
But the later patch will use relock_page_lruvec_xxx to fill up the gap.

According to Daniel Jordan's suggestion, I run 208 'dd' with on 104
containers on a 2s * 26cores * HT box with a modefied case:
  https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/tree/case-lru-file-readtwice

With this and later patches, the readtwice performance increases about
80% within concurrent containers.

Signed-off-by: Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
Cc: Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Vladimir Davydov <vdavydov.dev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Yang Shi <yang.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
Cc: Matthew Wilcox <willy-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Cc: Konstantin Khlebnikov <khlebnikov-XoJtRXgx1JseBXzfvpsJ4g@public.gmane.org>
Cc: Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
---
 include/linux/memcontrol.h | 35 ++++++++++++++++++++++
 include/linux/mmzone.h     |  2 ++
 mm/compaction.c            | 51 ++++++++++++++++++++------------
 mm/huge_memory.c           |  9 ++----
 mm/memcontrol.c            | 50 +++++++++++++++++++++++++-------
 mm/mlock.c                 | 18 +++++-------
 mm/mmzone.c                |  1 +
 mm/swap.c                  | 72 +++++++++++++++++-----------------------------
 mm/vmscan.c                | 57 ++++++++++++++++--------------------
 9 files changed, 170 insertions(+), 125 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index a7a0a1a5c8d5..b8a04f0a2ab8 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -424,6 +424,13 @@ static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg,
 
 struct mem_cgroup *get_mem_cgroup_from_page(struct page *page);
 
+struct lruvec *lock_page_lruvec_irq(struct page *page);
+struct lruvec *lock_page_lruvec_irqsave(struct page *page,
+						unsigned long *flags);
+
+void unlock_page_lruvec_irq(struct lruvec *lruvec);
+void unlock_page_lruvec_irqrestore(struct lruvec *lruvec, unsigned long flags);
+
 static inline
 struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css){
 	return css ? container_of(css, struct mem_cgroup, css) : NULL;
@@ -926,6 +933,34 @@ static inline void mem_cgroup_put(struct mem_cgroup *memcg)
 {
 }
 
+static inline struct lruvec *lock_page_lruvec_irq(struct page *page)
+{
+	struct pglist_data *pgdat = page_pgdat(page);
+
+	spin_lock_irq(&pgdat->__lruvec.lru_lock);
+	return &pgdat->__lruvec;
+}
+
+static inline struct lruvec *lock_page_lruvec_irqsave(struct page *page,
+		unsigned long *flagsp)
+{
+	struct pglist_data *pgdat = page_pgdat(page);
+
+	spin_lock_irqsave(&pgdat->__lruvec.lru_lock, *flagsp);
+	return &pgdat->__lruvec;
+}
+
+static inline void unlock_page_lruvec_irq(struct lruvec *lruvec)
+{
+	spin_unlock_irq(&lruvec->lru_lock);
+}
+
+static inline void unlock_page_lruvec_irqrestore(struct lruvec *lruvec,
+		unsigned long flags)
+{
+	spin_unlock_irqrestore(&lruvec->lru_lock, flags);
+}
+
 static inline struct mem_cgroup *
 mem_cgroup_iter(struct mem_cgroup *root,
 		struct mem_cgroup *prev,
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 462f6873905a..a7bdff94990d 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -308,6 +308,8 @@ struct lruvec {
 	atomic_long_t			inactive_age;
 	/* Refaults at the time of last reclaim cycle */
 	unsigned long			refaults;
+	/* per lruvec lru_lock for memcg */
+	spinlock_t			lru_lock;
 	/* Various lruvec state flags (enum lruvec_flags) */
 	unsigned long			flags;
 #ifdef CONFIG_MEMCG
diff --git a/mm/compaction.c b/mm/compaction.c
index 1baba328d089..4a773f0ffedf 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -786,7 +786,7 @@ static bool too_many_isolated(pg_data_t *pgdat)
 	unsigned long nr_scanned = 0, nr_isolated = 0;
 	struct lruvec *lruvec;
 	unsigned long flags = 0;
-	bool locked = false;
+	struct lruvec *locked_lruvec = NULL;
 	struct page *page = NULL, *valid_page = NULL;
 	unsigned long start_pfn = low_pfn;
 	bool skip_on_failure = false;
@@ -846,11 +846,20 @@ static bool too_many_isolated(pg_data_t *pgdat)
 		 * contention, to give chance to IRQs. Abort completely if
 		 * a fatal signal is pending.
 		 */
-		if (!(low_pfn % SWAP_CLUSTER_MAX)
-		    && compact_unlock_should_abort(&pgdat->lru_lock,
-					    flags, &locked, cc)) {
-			low_pfn = 0;
-			goto fatal_pending;
+		if (!(low_pfn % SWAP_CLUSTER_MAX)) {
+			if (locked_lruvec) {
+				unlock_page_lruvec_irqrestore(locked_lruvec, flags);
+				locked_lruvec = NULL;
+			}
+
+			if (fatal_signal_pending(current)) {
+				cc->contended = true;
+
+				low_pfn = 0;
+				goto fatal_pending;
+			}
+
+			cond_resched();
 		}
 
 		if (!pfn_valid_within(low_pfn))
@@ -919,10 +928,9 @@ static bool too_many_isolated(pg_data_t *pgdat)
 			 */
 			if (unlikely(__PageMovable(page)) &&
 					!PageIsolated(page)) {
-				if (locked) {
-					spin_unlock_irqrestore(&pgdat->lru_lock,
-									flags);
-					locked = false;
+				if (locked_lruvec) {
+					unlock_page_lruvec_irqrestore(locked_lruvec, flags);
+					locked_lruvec = NULL;
 				}
 
 				if (!isolate_movable_page(page, isolate_mode))
@@ -965,10 +973,16 @@ static bool too_many_isolated(pg_data_t *pgdat)
 			goto isolate_fail;
 		}
 
+		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+
 		/* If we already hold the lock, we can skip some rechecking */
-		if (!locked) {
-			locked = compact_lock_irqsave(&pgdat->lru_lock,
-								&flags, cc);
+		if (lruvec != locked_lruvec) {
+			if (locked_lruvec) {
+				unlock_page_lruvec_irqrestore(locked_lruvec, flags);
+				locked_lruvec = NULL;
+			}
+			compact_lock_irqsave(&lruvec->lru_lock, &flags, cc);
+			locked_lruvec = lruvec;
 
 			/* Try get exclusive access under lock */
 			if (!skip_updated) {
@@ -988,7 +1002,6 @@ static bool too_many_isolated(pg_data_t *pgdat)
 			}
 		}
 
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
 		VM_BUG_ON_PAGE(PageCompound(page), page);
 
@@ -1025,9 +1038,9 @@ static bool too_many_isolated(pg_data_t *pgdat)
 		 * page anyway.
 		 */
 		if (nr_isolated) {
-			if (locked) {
-				spin_unlock_irqrestore(&pgdat->lru_lock, flags);
-				locked = false;
+			if (locked_lruvec) {
+				unlock_page_lruvec_irqrestore(locked_lruvec, flags);
+				locked_lruvec = NULL;
 			}
 			putback_movable_pages(&cc->migratepages);
 			cc->nr_migratepages = 0;
@@ -1052,8 +1065,8 @@ static bool too_many_isolated(pg_data_t *pgdat)
 		low_pfn = end_pfn;
 
 isolate_abort:
-	if (locked)
-		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+	if (locked_lruvec)
+		unlock_page_lruvec_irqrestore(locked_lruvec, flags);
 
 	/*
 	 * Updated the cached scanner pfn once the pageblock has been scanned
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 3835f87d03fd..7af56d0fb044 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2452,7 +2452,7 @@ void lru_add_page_tail(struct page *head, struct page *page_tail,
 
 	VM_BUG_ON_PAGE(PageCompound(page_tail), head);
 	VM_BUG_ON_PAGE(PageLRU(page_tail), head);
-	lockdep_assert_held(&lruvec_pgdat(lruvec)->lru_lock);
+	lockdep_assert_held(&lruvec->lru_lock);
 
 	if (!list)
 		SetPageLRU(page_tail);
@@ -2545,15 +2545,12 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 				pgoff_t end)
 {
 	struct page *head = compound_head(page);
-	pg_data_t *pgdat = page_pgdat(head);
 	struct lruvec *lruvec;
 	struct address_space *swap_cache = NULL;
 	unsigned long offset = 0;
 	unsigned long flags;
 	int i;
 
-	lruvec = mem_cgroup_page_lruvec(head, pgdat);
-
 	/* complete memcg works before add pages to LRU */
 	mem_cgroup_split_huge_fixup(head);
 
@@ -2566,7 +2563,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 	}
 
 	/* Lru list would be changed, don't care head's LRU bit. */
-	spin_lock_irqsave(&pgdat->lru_lock, flags);
+	lruvec = lock_page_lruvec_irqsave(head, &flags);
 
 	for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
 		__split_huge_page_tail(head, i, lruvec, list);
@@ -2585,7 +2582,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 					head + i, 0);
 		}
 	}
-	spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+	unlock_page_lruvec_irqrestore(lruvec, flags);
 
 	ClearPageCompound(head);
 
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7d7b861a948c..b0c156da60fe 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1219,7 +1219,7 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd
 		goto out;
 	}
 
-	memcg = page->mem_cgroup;
+	memcg = READ_ONCE(page->mem_cgroup);
 	/*
 	 * Swapcache readahead pages are added to the LRU - and
 	 * possibly migrated - before they are charged.
@@ -1240,6 +1240,37 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd
 	return lruvec;
 }
 
+/* page must be isolated */
+struct lruvec *lock_page_lruvec_irq(struct page *page)
+{
+	struct lruvec *lruvec;
+
+	lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+	spin_lock_irq(&lruvec->lru_lock);
+
+	return lruvec;
+}
+
+struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags)
+{
+	struct lruvec *lruvec;
+
+	lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+	spin_lock_irqsave(&lruvec->lru_lock, *flags);
+
+	return lruvec;
+}
+
+void unlock_page_lruvec_irq(struct lruvec *lruvec)
+{
+	spin_unlock_irq(&lruvec->lru_lock);
+}
+
+void unlock_page_lruvec_irqrestore(struct lruvec *lruvec, unsigned long flags)
+{
+	spin_unlock_irqrestore(&lruvec->lru_lock, flags);
+}
+
 /**
  * mem_cgroup_update_lru_size - account for adding or removing an lru page
  * @lruvec: mem_cgroup per zone lru vector
@@ -2576,7 +2607,6 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
 			  bool lrucare)
 {
 	struct lruvec *lruvec = NULL;
-	pg_data_t *pgdat;
 
 	VM_BUG_ON_PAGE(page->mem_cgroup, page);
 
@@ -2585,14 +2615,12 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
 	 * may already be on some other mem_cgroup's LRU.  Take care of it.
 	 */
 	if (lrucare) {
-		pgdat = page_pgdat(page);
-		spin_lock_irq(&pgdat->lru_lock);
-
 		if (TestClearPageLRU(page)) {
-			lruvec = mem_cgroup_page_lruvec(page, pgdat);
+			lruvec = lock_page_lruvec_irq(page);
+
 			del_page_from_lru_list(page, lruvec, page_lru(page));
-		} else
-			spin_unlock_irq(&pgdat->lru_lock);
+			unlock_page_lruvec_irq(lruvec);
+		}
 	}
 	/*
 	 * Nobody should be changing or seriously looking at
@@ -2611,11 +2639,11 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
 	page->mem_cgroup = memcg;
 
 	if (lrucare && lruvec) {
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+		lruvec = lock_page_lruvec_irq(page);
 
 		VM_BUG_ON_PAGE(PageLRU(page), page);
 		add_page_to_lru_list(page, lruvec, page_lru(page));
-		spin_unlock_irq(&pgdat->lru_lock);
+		unlock_page_lruvec_irq(lruvec);
 		SetPageLRU(page);
 	}
 }
@@ -2913,7 +2941,7 @@ void __memcg_kmem_uncharge(struct page *page, int order)
 
 /*
  * Because tail pages are not marked as "used", set it. We're under
- * pgdat->lru_lock and migration entries setup in all page mappings.
+ * lruvec->lru_lock and migration entries setup in all page mappings.
  */
 void mem_cgroup_split_huge_fixup(struct page *head)
 {
diff --git a/mm/mlock.c b/mm/mlock.c
index a43b3da78541..d285348b147e 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -163,7 +163,7 @@ unsigned int munlock_vma_page(struct page *page)
 {
 	int nr_pages;
 	bool clearlru = false;
-	pg_data_t *pgdat = page_pgdat(page);
+	struct lruvec *lruvec;
 
 	/* For try_to_munlock() and to serialize with page migration */
 	BUG_ON(!PageLocked(page));
@@ -177,7 +177,7 @@ unsigned int munlock_vma_page(struct page *page)
 	 */
 	get_page(page);
 	clearlru = TestClearPageLRU(page);
-	spin_lock_irq(&pgdat->lru_lock);
+	lruvec = lock_page_lruvec_irq(page);
 
 	if (!TestClearPageMlocked(page)) {
 		if (clearlru)
@@ -186,7 +186,7 @@ unsigned int munlock_vma_page(struct page *page)
 		 * Potentially, PTE-mapped THP: do not skip the rest PTEs
 		 * Reuse lock as memory barrier for release_pages racing.
 		 */
-		spin_unlock_irq(&pgdat->lru_lock);
+		unlock_page_lruvec_irq(lruvec);
 		put_page(page);
 		return 0;
 	}
@@ -195,14 +195,11 @@ unsigned int munlock_vma_page(struct page *page)
 	__mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
 
 	if (clearlru) {
-		struct lruvec *lruvec;
-
-		lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
 		del_page_from_lru_list(page, lruvec, page_lru(page));
-		spin_unlock_irq(&pgdat->lru_lock);
+		unlock_page_lruvec_irq(lruvec);
 		__munlock_isolated_page(page);
 	} else {
-		spin_unlock_irq(&pgdat->lru_lock);
+		unlock_page_lruvec_irq(lruvec);
 		put_page(page);
 		__munlock_isolation_failed(page);
 	}
@@ -289,7 +286,6 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 	pagevec_init(&pvec_putback);
 
 	/* Phase 1: page isolation */
-	spin_lock_irq(&zone->zone_pgdat->lru_lock);
 	for (i = 0; i < nr; i++) {
 		struct page *page = pvec->pages[i];
 		struct lruvec *lruvec;
@@ -309,8 +305,9 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 		 * We already have pin from follow_page_mask()
 		 * so we can spare the get_page() here.
 		 */
-		lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+		lruvec = lock_page_lruvec_irq(page);
 		del_page_from_lru_list(page, lruvec, page_lru(page));
+		unlock_page_lruvec_irq(lruvec);
 		continue;
 
 		/*
@@ -323,7 +320,6 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 		pagevec_add(&pvec_putback, pvec->pages[i]);
 		pvec->pages[i] = NULL;
 	}
-	spin_unlock_irq(&zone->zone_pgdat->lru_lock);
 	__mod_zone_page_state(zone, NR_MLOCK, delta_munlocked);
 
 	/* Now we can release pins of pages that we are not munlocking */
diff --git a/mm/mmzone.c b/mm/mmzone.c
index 4686fdc23bb9..3750a90ed4a0 100644
--- a/mm/mmzone.c
+++ b/mm/mmzone.c
@@ -91,6 +91,7 @@ void lruvec_init(struct lruvec *lruvec)
 	enum lru_list lru;
 
 	memset(lruvec, 0, sizeof(struct lruvec));
+	spin_lock_init(&lruvec->lru_lock);
 
 	for_each_lru(lru)
 		INIT_LIST_HEAD(&lruvec->lists[lru]);
diff --git a/mm/swap.c b/mm/swap.c
index 16af7c8369fe..50c856246f84 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -60,14 +60,12 @@
 static void __page_cache_release(struct page *page)
 {
 	if (TestClearPageLRU(page)) {
-		pg_data_t *pgdat = page_pgdat(page);
 		struct lruvec *lruvec;
 		unsigned long flags;
 
-		spin_lock_irqsave(&pgdat->lru_lock, flags);
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+		lruvec = lock_page_lruvec_irqsave(page, &flags);
 		del_page_from_lru_list(page, lruvec, page_off_lru(page));
-		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+		unlock_page_lruvec_irqrestore(lruvec, flags);
 	}
 	__ClearPageWaiters(page);
 }
@@ -190,33 +188,22 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 	void *arg, bool isolation)
 {
 	int i;
-	struct pglist_data *pgdat = NULL;
-	struct lruvec *lruvec;
+	struct lruvec *lruvec = NULL;
 	unsigned long flags = 0;
 
 	for (i = 0; i < pagevec_count(pvec); i++) {
 		struct page *page = pvec->pages[i];
-		struct pglist_data *pagepgdat = page_pgdat(page);
 
 		if (isolation && !TestClearPageLRU(page))
 			continue;
 
-		/* every page should be isolated from lru */
-		if (pagepgdat != pgdat) {
-			if (pgdat)
-				spin_unlock_irqrestore(&pgdat->lru_lock, flags);
-			pgdat = pagepgdat;
-			spin_lock_irqsave(&pgdat->lru_lock, flags);
-		}
-
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+		lruvec = lock_page_lruvec_irqsave(page, &flags);
 		(*move_fn)(page, lruvec, arg);
+		unlock_page_lruvec_irqrestore(lruvec, flags);
 
 		if (isolation)
 			SetPageLRU(page);
 	}
-	if (pgdat)
-		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
 	release_pages(pvec->pages, pvec->nr);
 	pagevec_reinit(pvec);
 }
@@ -328,12 +315,12 @@ static inline void activate_page_drain(int cpu)
 
 void activate_page(struct page *page)
 {
-	pg_data_t *pgdat = page_pgdat(page);
+	struct lruvec *lruvec;
 
 	page = compound_head(page);
-	spin_lock_irq(&pgdat->lru_lock);
-	__activate_page(page, mem_cgroup_page_lruvec(page, pgdat), NULL);
-	spin_unlock_irq(&pgdat->lru_lock);
+	lruvec = lock_page_lruvec_irq(page);
+	__activate_page(page, lruvec, NULL);
+	unlock_page_lruvec_irq(lruvec);
 }
 #endif
 
@@ -783,8 +770,7 @@ void release_pages(struct page **pages, int nr)
 {
 	int i;
 	LIST_HEAD(pages_to_free);
-	struct pglist_data *locked_pgdat = NULL;
-	struct lruvec *lruvec;
+	struct lruvec *lruvec = NULL;
 	unsigned long uninitialized_var(flags);
 	unsigned int uninitialized_var(lock_batch);
 
@@ -794,21 +780,20 @@ void release_pages(struct page **pages, int nr)
 		/*
 		 * Make sure the IRQ-safe lock-holding time does not get
 		 * excessive with a continuous string of pages from the
-		 * same pgdat. The lock is held only if pgdat != NULL.
+		 * same lruvec. The lock is held only if lruvec != NULL.
 		 */
-		if (locked_pgdat && ++lock_batch == SWAP_CLUSTER_MAX) {
-			spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags);
-			locked_pgdat = NULL;
+		if (lruvec && ++lock_batch == SWAP_CLUSTER_MAX) {
+			unlock_page_lruvec_irqrestore(lruvec, flags);
+			lruvec = NULL;
 		}
 
 		if (is_huge_zero_page(page))
 			continue;
 
 		if (is_zone_device_page(page)) {
-			if (locked_pgdat) {
-				spin_unlock_irqrestore(&locked_pgdat->lru_lock,
-						       flags);
-				locked_pgdat = NULL;
+			if (lruvec) {
+				unlock_page_lruvec_irqrestore(lruvec, flags);
+				lruvec = NULL;
 			}
 			/*
 			 * ZONE_DEVICE pages that return 'false' from
@@ -827,27 +812,24 @@ void release_pages(struct page **pages, int nr)
 			continue;
 
 		if (PageCompound(page)) {
-			if (locked_pgdat) {
-				spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags);
-				locked_pgdat = NULL;
+			if (lruvec) {
+				unlock_page_lruvec_irqrestore(lruvec, flags);
+				lruvec = NULL;
 			}
 			__put_compound_page(page);
 			continue;
 		}
 
 		if (TestClearPageLRU(page)) {
-			struct pglist_data *pgdat = page_pgdat(page);
+			struct lruvec *new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
 
-			if (pgdat != locked_pgdat) {
-				if (locked_pgdat)
-					spin_unlock_irqrestore(&locked_pgdat->lru_lock,
-									flags);
+			if (new_lruvec != lruvec) {
+				if (lruvec)
+					unlock_page_lruvec_irqrestore(lruvec, flags);
 				lock_batch = 0;
-				locked_pgdat = pgdat;
-				spin_lock_irqsave(&locked_pgdat->lru_lock, flags);
+				lruvec = lock_page_lruvec_irqsave(page, &flags);
 			}
 
-			lruvec = mem_cgroup_page_lruvec(page, locked_pgdat);
 			del_page_from_lru_list(page, lruvec, page_off_lru(page));
 		}
 
@@ -857,8 +839,8 @@ void release_pages(struct page **pages, int nr)
 
 		list_add(&page->lru, &pages_to_free);
 	}
-	if (locked_pgdat)
-		spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags);
+	if (lruvec)
+		unlock_page_lruvec_irqrestore(lruvec, flags);
 
 	mem_cgroup_uncharge_list(&pages_to_free);
 	free_unref_page_list(&pages_to_free);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index efaa4f41044e..a58cd5ee9ea1 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1757,14 +1757,12 @@ int isolate_lru_page(struct page *page)
 
 	get_page(page);
 	if (TestClearPageLRU(page)) {
-		pg_data_t *pgdat = page_pgdat(page);
 		struct lruvec *lruvec;
 		int lru = page_lru(page);
 
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
-		spin_lock_irq(&pgdat->lru_lock);
+		lruvec = lock_page_lruvec_irq(page);
 		del_page_from_lru_list(page, lruvec, lru);
-		spin_unlock_irq(&pgdat->lru_lock);
+		unlock_page_lruvec_irq(lruvec);
 		ret = 0;
 	} else
 		put_page(page);
@@ -1832,7 +1830,6 @@ static int too_many_isolated(struct pglist_data *pgdat, int file,
 static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 						     struct list_head *list)
 {
-	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
 	int nr_pages, nr_moved = 0;
 	LIST_HEAD(pages_to_free);
 	struct page *page;
@@ -1843,9 +1840,9 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 		VM_BUG_ON_PAGE(PageLRU(page), page);
 		list_del(&page->lru);
 		if (unlikely(!page_evictable(page))) {
-			spin_unlock_irq(&pgdat->lru_lock);
+			spin_unlock_irq(&lruvec->lru_lock);
 			putback_lru_page(page);
-			spin_lock_irq(&pgdat->lru_lock);
+			spin_lock_irq(&lruvec->lru_lock);
 			continue;
 		}
 
@@ -1866,18 +1863,16 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 			__ClearPageActive(page);
 
 			if (unlikely(PageCompound(page))) {
-				spin_unlock_irq(&pgdat->lru_lock);
+				spin_unlock_irq(&lruvec->lru_lock);
 				(*get_compound_page_dtor(page))(page);
-				spin_lock_irq(&pgdat->lru_lock);
+				spin_lock_irq(&lruvec->lru_lock);
 			} else
 				list_add(&page->lru, &pages_to_free);
 			continue;
 		}
 
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 		lru = page_lru(page);
 		nr_pages = hpage_nr_pages(page);
-
 		update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
 		list_add(&page->lru, &lruvec->lists[lru]);
 		nr_moved += nr_pages;
@@ -1938,7 +1933,7 @@ static int current_may_throttle(void)
 
 	lru_add_drain();
 
-	spin_lock_irq(&pgdat->lru_lock);
+	spin_lock_irq(&lruvec->lru_lock);
 
 	nr_taken = isolate_lru_pages(nr_to_scan, lruvec, &page_list,
 				     &nr_scanned, sc, lru);
@@ -1950,7 +1945,7 @@ static int current_may_throttle(void)
 	if (!cgroup_reclaim(sc))
 		__count_vm_events(item, nr_scanned);
 	__count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned);
-	spin_unlock_irq(&pgdat->lru_lock);
+	spin_unlock_irq(&lruvec->lru_lock);
 
 	if (nr_taken == 0)
 		return 0;
@@ -1958,7 +1953,7 @@ static int current_may_throttle(void)
 	nr_reclaimed = shrink_page_list(&page_list, pgdat, sc, 0,
 				&stat, false);
 
-	spin_lock_irq(&pgdat->lru_lock);
+	spin_lock_irq(&lruvec->lru_lock);
 
 	item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT;
 	if (!cgroup_reclaim(sc))
@@ -1971,7 +1966,7 @@ static int current_may_throttle(void)
 
 	__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
 
-	spin_unlock_irq(&pgdat->lru_lock);
+	spin_unlock_irq(&lruvec->lru_lock);
 
 	mem_cgroup_uncharge_list(&page_list);
 	free_unref_page_list(&page_list);
@@ -2024,7 +2019,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 
 	lru_add_drain();
 
-	spin_lock_irq(&pgdat->lru_lock);
+	spin_lock_irq(&lruvec->lru_lock);
 
 	nr_taken = isolate_lru_pages(nr_to_scan, lruvec, &l_hold,
 				     &nr_scanned, sc, lru);
@@ -2035,7 +2030,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 	__count_vm_events(PGREFILL, nr_scanned);
 	__count_memcg_events(lruvec_memcg(lruvec), PGREFILL, nr_scanned);
 
-	spin_unlock_irq(&pgdat->lru_lock);
+	spin_unlock_irq(&lruvec->lru_lock);
 
 	while (!list_empty(&l_hold)) {
 		cond_resched();
@@ -2081,7 +2076,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 	/*
 	 * Move pages back to the lru list.
 	 */
-	spin_lock_irq(&pgdat->lru_lock);
+	spin_lock_irq(&lruvec->lru_lock);
 	/*
 	 * Count referenced pages from currently used mappings as rotated,
 	 * even though only some of them are actually re-activated.  This
@@ -2099,7 +2094,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 	__count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate);
 
 	__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
-	spin_unlock_irq(&pgdat->lru_lock);
+	spin_unlock_irq(&lruvec->lru_lock);
 
 	mem_cgroup_uncharge_list(&l_active);
 	free_unref_page_list(&l_active);
@@ -2248,7 +2243,6 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
 	struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
 	u64 fraction[2];
 	u64 denominator = 0;	/* gcc */
-	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
 	unsigned long anon_prio, file_prio;
 	enum scan_balance scan_balance;
 	unsigned long anon, file;
@@ -2326,7 +2320,7 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
 	file  = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE, MAX_NR_ZONES) +
 		lruvec_lru_size(lruvec, LRU_INACTIVE_FILE, MAX_NR_ZONES);
 
-	spin_lock_irq(&pgdat->lru_lock);
+	spin_lock_irq(&lruvec->lru_lock);
 	if (unlikely(reclaim_stat->recent_scanned[0] > anon / 4)) {
 		reclaim_stat->recent_scanned[0] /= 2;
 		reclaim_stat->recent_rotated[0] /= 2;
@@ -2347,7 +2341,7 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
 
 	fp = file_prio * (reclaim_stat->recent_scanned[1] + 1);
 	fp /= reclaim_stat->recent_rotated[1] + 1;
-	spin_unlock_irq(&pgdat->lru_lock);
+	spin_unlock_irq(&lruvec->lru_lock);
 
 	fraction[0] = ap;
 	fraction[1] = fp;
@@ -4324,24 +4318,21 @@ int page_evictable(struct page *page)
  */
 void check_move_unevictable_pages(struct pagevec *pvec)
 {
-	struct lruvec *lruvec;
-	struct pglist_data *pgdat = NULL;
+	struct lruvec *lruvec = NULL;
 	int pgscanned = 0;
 	int pgrescued = 0;
 	int i;
 
 	for (i = 0; i < pvec->nr; i++) {
 		struct page *page = pvec->pages[i];
-		struct pglist_data *pagepgdat = page_pgdat(page);
+		struct lruvec *new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
 
 		pgscanned++;
-		if (pagepgdat != pgdat) {
-			if (pgdat)
-				spin_unlock_irq(&pgdat->lru_lock);
-			pgdat = pagepgdat;
-			spin_lock_irq(&pgdat->lru_lock);
+		if (lruvec != new_lruvec) {
+			if (lruvec)
+				unlock_page_lruvec_irq(lruvec);
+			lruvec = lock_page_lruvec_irq(page);
 		}
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
 		if (!TestClearPageLRU(page) || !PageUnevictable(page))
 			continue;
@@ -4358,10 +4349,10 @@ void check_move_unevictable_pages(struct pagevec *pvec)
 		}
 	}
 
-	if (pgdat) {
+	if (lruvec) {
 		__count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued);
 		__count_vm_events(UNEVICTABLE_PGSCANNED, pgscanned);
-		spin_unlock_irq(&pgdat->lru_lock);
+		unlock_page_lruvec_irq(lruvec);
 	}
 }
 EXPORT_SYMBOL_GPL(check_move_unevictable_pages);
-- 
1.8.3.1

[PATCH v9 14/20] mm/lru: introduce the relock_page_lruvec function

[Alex Shi]

During the lruvec locking, a new page's lruvec is may same as
previous one. Thus we could save a re-locking, and only
change lock iff lruvec is new.

Function named relock_page_lruvec following Hugh Dickins' patch.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
---
 include/linux/memcontrol.h | 36 ++++++++++++++++++++++++++++++++++++
 mm/vmscan.c                |  8 ++------
 2 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index b8a04f0a2ab8..f60009580d2a 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1307,6 +1307,42 @@ static inline void dec_lruvec_page_state(struct page *page,
 	mod_lruvec_page_state(page, idx, -1);
 }
 
+/* Don't lock again iff page's lruvec locked */
+static inline struct lruvec *relock_page_lruvec_irq(struct page *page,
+		struct lruvec *locked_lruvec)
+{
+	struct pglist_data *pgdat = page_pgdat(page);
+	struct lruvec *lruvec;
+
+	lruvec = mem_cgroup_page_lruvec(page, pgdat);
+
+	if (likely(locked_lruvec == lruvec))
+		return lruvec;
+
+	if (unlikely(locked_lruvec))
+		unlock_page_lruvec_irq(locked_lruvec);
+
+	return lock_page_lruvec_irq(page);
+}
+
+/* Don't lock again iff page's lruvec locked */
+static inline struct lruvec *relock_page_lruvec_irqsave(struct page *page,
+		struct lruvec *locked_lruvec, unsigned long *flags)
+{
+	struct pglist_data *pgdat = page_pgdat(page);
+	struct lruvec *lruvec;
+
+	lruvec = mem_cgroup_page_lruvec(page, pgdat);
+
+	if (likely(locked_lruvec == lruvec))
+		return lruvec;
+
+	if (unlikely(locked_lruvec))
+		unlock_page_lruvec_irqrestore(locked_lruvec, *flags);
+
+	return lock_page_lruvec_irqsave(page, flags);
+}
+
 #ifdef CONFIG_CGROUP_WRITEBACK
 
 struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index a58cd5ee9ea1..de925bd629eb 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4325,14 +4325,10 @@ void check_move_unevictable_pages(struct pagevec *pvec)
 
 	for (i = 0; i < pvec->nr; i++) {
 		struct page *page = pvec->pages[i];
-		struct lruvec *new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
 
 		pgscanned++;
-		if (lruvec != new_lruvec) {
-			if (lruvec)
-				unlock_page_lruvec_irq(lruvec);
-			lruvec = lock_page_lruvec_irq(page);
-		}
+
+		lruvec = relock_page_lruvec_irq(page, lruvec);
 
 		if (!TestClearPageLRU(page) || !PageUnevictable(page))
 			continue;
-- 
1.8.3.1

[PATCH v9 14/20] mm/lru: introduce the relock_page_lruvec function

[Alex Shi]

During the lruvec locking, a new page's lruvec is may same as
previous one. Thus we could save a re-locking, and only
change lock iff lruvec is new.

Function named relock_page_lruvec following Hugh Dickins' patch.

Signed-off-by: Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
Cc: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Cc: Andrey Ryabinin <aryabinin-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org>
Cc: Matthew Wilcox <willy-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Cc: Mel Gorman <mgorman-3eNAlZScCAx27rWaFMvyedHuzzzSOjJt@public.gmane.org>
Cc: Konstantin Khlebnikov <khlebnikov-XoJtRXgx1JseBXzfvpsJ4g@public.gmane.org>
Cc: Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
---
 include/linux/memcontrol.h | 36 ++++++++++++++++++++++++++++++++++++
 mm/vmscan.c                |  8 ++------
 2 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index b8a04f0a2ab8..f60009580d2a 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1307,6 +1307,42 @@ static inline void dec_lruvec_page_state(struct page *page,
 	mod_lruvec_page_state(page, idx, -1);
 }
 
+/* Don't lock again iff page's lruvec locked */
+static inline struct lruvec *relock_page_lruvec_irq(struct page *page,
+		struct lruvec *locked_lruvec)
+{
+	struct pglist_data *pgdat = page_pgdat(page);
+	struct lruvec *lruvec;
+
+	lruvec = mem_cgroup_page_lruvec(page, pgdat);
+
+	if (likely(locked_lruvec == lruvec))
+		return lruvec;
+
+	if (unlikely(locked_lruvec))
+		unlock_page_lruvec_irq(locked_lruvec);
+
+	return lock_page_lruvec_irq(page);
+}
+
+/* Don't lock again iff page's lruvec locked */
+static inline struct lruvec *relock_page_lruvec_irqsave(struct page *page,
+		struct lruvec *locked_lruvec, unsigned long *flags)
+{
+	struct pglist_data *pgdat = page_pgdat(page);
+	struct lruvec *lruvec;
+
+	lruvec = mem_cgroup_page_lruvec(page, pgdat);
+
+	if (likely(locked_lruvec == lruvec))
+		return lruvec;
+
+	if (unlikely(locked_lruvec))
+		unlock_page_lruvec_irqrestore(locked_lruvec, *flags);
+
+	return lock_page_lruvec_irqsave(page, flags);
+}
+
 #ifdef CONFIG_CGROUP_WRITEBACK
 
 struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index a58cd5ee9ea1..de925bd629eb 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4325,14 +4325,10 @@ void check_move_unevictable_pages(struct pagevec *pvec)
 
 	for (i = 0; i < pvec->nr; i++) {
 		struct page *page = pvec->pages[i];
-		struct lruvec *new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
 
 		pgscanned++;
-		if (lruvec != new_lruvec) {
-			if (lruvec)
-				unlock_page_lruvec_irq(lruvec);
-			lruvec = lock_page_lruvec_irq(page);
-		}
+
+		lruvec = relock_page_lruvec_irq(page, lruvec);
 
 		if (!TestClearPageLRU(page) || !PageUnevictable(page))
 			continue;
-- 
1.8.3.1

[PATCH v9 15/20] mm/mlock: optimize munlock_pagevec by relocking

[Alex Shi]

During the pagevec locking, a new page's lruvec is may same as
previous one. Thus we could save a re-locking, and only
change lock iff lruvec is newer.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-kernel@vger.kernel.org
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
---
 mm/mlock.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c
index d285348b147e..236a29b791f4 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -281,6 +281,7 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 	int nr = pagevec_count(pvec);
 	int delta_munlocked = -nr;
 	struct pagevec pvec_putback;
+	struct lruvec *lruvec = NULL;
 	int pgrescued = 0;
 
 	pagevec_init(&pvec_putback);
@@ -288,7 +289,6 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 	/* Phase 1: page isolation */
 	for (i = 0; i < nr; i++) {
 		struct page *page = pvec->pages[i];
-		struct lruvec *lruvec;
 
 		if (!TestClearPageMlocked(page)) {
 			delta_munlocked++;
@@ -305,9 +305,8 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 		 * We already have pin from follow_page_mask()
 		 * so we can spare the get_page() here.
 		 */
-		lruvec = lock_page_lruvec_irq(page);
+		lruvec = relock_page_lruvec_irq(page, lruvec);
 		del_page_from_lru_list(page, lruvec, page_lru(page));
-		unlock_page_lruvec_irq(lruvec);
 		continue;
 
 		/*
@@ -320,6 +319,8 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 		pagevec_add(&pvec_putback, pvec->pages[i]);
 		pvec->pages[i] = NULL;
 	}
+	if (lruvec)
+		unlock_page_lruvec_irq(lruvec);
 	__mod_zone_page_state(zone, NR_MLOCK, delta_munlocked);
 
 	/* Now we can release pins of pages that we are not munlocking */
-- 
1.8.3.1

[PATCH v9 15/20] mm/mlock: optimize munlock_pagevec by relocking

[Alex Shi]

During the pagevec locking, a new page's lruvec is may same as
previous one. Thus we could save a re-locking, and only
change lock iff lruvec is newer.

Signed-off-by: Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
Cc: Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
---
 mm/mlock.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c
index d285348b147e..236a29b791f4 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -281,6 +281,7 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 	int nr = pagevec_count(pvec);
 	int delta_munlocked = -nr;
 	struct pagevec pvec_putback;
+	struct lruvec *lruvec = NULL;
 	int pgrescued = 0;
 
 	pagevec_init(&pvec_putback);
@@ -288,7 +289,6 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 	/* Phase 1: page isolation */
 	for (i = 0; i < nr; i++) {
 		struct page *page = pvec->pages[i];
-		struct lruvec *lruvec;
 
 		if (!TestClearPageMlocked(page)) {
 			delta_munlocked++;
@@ -305,9 +305,8 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 		 * We already have pin from follow_page_mask()
 		 * so we can spare the get_page() here.
 		 */
-		lruvec = lock_page_lruvec_irq(page);
+		lruvec = relock_page_lruvec_irq(page, lruvec);
 		del_page_from_lru_list(page, lruvec, page_lru(page));
-		unlock_page_lruvec_irq(lruvec);
 		continue;
 
 		/*
@@ -320,6 +319,8 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 		pagevec_add(&pvec_putback, pvec->pages[i]);
 		pvec->pages[i] = NULL;
 	}
+	if (lruvec)
+		unlock_page_lruvec_irq(lruvec);
 	__mod_zone_page_state(zone, NR_MLOCK, delta_munlocked);
 
 	/* Now we can release pins of pages that we are not munlocking */
-- 
1.8.3.1

[PATCH v9 16/20] mm/swap: only change the lru_lock iff page's lruvec is different

[Alex Shi]

Since we introduced relock_page_lruvec, we could use it in more place
to reduce spin_locks.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Hugh Dickins <hughd@google.com>
Cc: linux-kernel@vger.kernel.org
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
---
 mm/swap.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index 50c856246f84..74e03589adde 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -197,13 +197,15 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 		if (isolation && !TestClearPageLRU(page))
 			continue;
 
-		lruvec = lock_page_lruvec_irqsave(page, &flags);
+		lruvec = relock_page_lruvec_irqsave(page, lruvec, &flags);
 		(*move_fn)(page, lruvec, arg);
-		unlock_page_lruvec_irqrestore(lruvec, flags);
 
 		if (isolation)
 			SetPageLRU(page);
 	}
+	if (lruvec)
+		unlock_page_lruvec_irqrestore(lruvec, flags);
+
 	release_pages(pvec->pages, pvec->nr);
 	pagevec_reinit(pvec);
 }
@@ -821,14 +823,11 @@ void release_pages(struct page **pages, int nr)
 		}
 
 		if (TestClearPageLRU(page)) {
-			struct lruvec *new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+			struct lruvec *pre_lruvec = lruvec;
 
-			if (new_lruvec != lruvec) {
-				if (lruvec)
-					unlock_page_lruvec_irqrestore(lruvec, flags);
+			lruvec = relock_page_lruvec_irqsave(page, lruvec, &flags);
+			if (pre_lruvec != lruvec)
 				lock_batch = 0;
-				lruvec = lock_page_lruvec_irqsave(page, &flags);
-			}
 
 			del_page_from_lru_list(page, lruvec, page_off_lru(page));
 		}
-- 
1.8.3.1

[PATCH v9 16/20] mm/swap: only change the lru_lock iff page's lruvec is different

[Alex Shi]

Since we introduced relock_page_lruvec, we could use it in more place
to reduce spin_locks.

Signed-off-by: Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
Cc: Konstantin Khlebnikov <khlebnikov-XoJtRXgx1JseBXzfvpsJ4g@public.gmane.org>
Cc: Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
---
 mm/swap.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index 50c856246f84..74e03589adde 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -197,13 +197,15 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 		if (isolation && !TestClearPageLRU(page))
 			continue;
 
-		lruvec = lock_page_lruvec_irqsave(page, &flags);
+		lruvec = relock_page_lruvec_irqsave(page, lruvec, &flags);
 		(*move_fn)(page, lruvec, arg);
-		unlock_page_lruvec_irqrestore(lruvec, flags);
 
 		if (isolation)
 			SetPageLRU(page);
 	}
+	if (lruvec)
+		unlock_page_lruvec_irqrestore(lruvec, flags);
+
 	release_pages(pvec->pages, pvec->nr);
 	pagevec_reinit(pvec);
 }
@@ -821,14 +823,11 @@ void release_pages(struct page **pages, int nr)
 		}
 
 		if (TestClearPageLRU(page)) {
-			struct lruvec *new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+			struct lruvec *pre_lruvec = lruvec;
 
-			if (new_lruvec != lruvec) {
-				if (lruvec)
-					unlock_page_lruvec_irqrestore(lruvec, flags);
+			lruvec = relock_page_lruvec_irqsave(page, lruvec, &flags);
+			if (pre_lruvec != lruvec)
 				lock_batch = 0;
-				lruvec = lock_page_lruvec_irqsave(page, &flags);
-			}
 
 			del_page_from_lru_list(page, lruvec, page_off_lru(page));
 		}
-- 
1.8.3.1

[PATCH v9 17/20] mm/pgdat: remove pgdat lru_lock

[Alex Shi]

Now pgdat.lru_lock was replaced by lruvec lock. It's not used anymore.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Cc: cgroups@vger.kernel.org
---
 include/linux/mmzone.h | 1 -
 mm/page_alloc.c        | 1 -
 2 files changed, 2 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index a7bdff94990d..f1ff6713ac06 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -768,7 +768,6 @@ struct deferred_split {
 
 	/* Write-intensive fields used by page reclaim */
 	ZONE_PADDING(_pad1_)
-	spinlock_t		lru_lock;
 
 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
 	/*
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3c4eb750a199..8c7df304bcd1 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6709,7 +6709,6 @@ static void __meminit pgdat_init_internals(struct pglist_data *pgdat)
 	init_waitqueue_head(&pgdat->pfmemalloc_wait);
 
 	pgdat_page_ext_init(pgdat);
-	spin_lock_init(&pgdat->lru_lock);
 	lruvec_init(&pgdat->__lruvec);
 }
 
-- 
1.8.3.1

[PATCH v9 18/20] mm/lru: revise the comments of lru_lock

[Alex Shi]

From: Hugh Dickins <hughd@google.com>

Since we changed the pgdat->lru_lock to lruvec->lru_lock, it's time to
fix the incorrect comments in code. Also fixed some zone->lru_lock comment
error from ancient time. etc.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Jann Horn <jannh@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: cgroups@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
---
 Documentation/admin-guide/cgroup-v1/memcg_test.rst | 15 +++------------
 Documentation/admin-guide/cgroup-v1/memory.rst     |  8 ++++----
 Documentation/trace/events-kmem.rst                |  2 +-
 Documentation/vm/unevictable-lru.rst               | 22 ++++++++--------------
 include/linux/mm_types.h                           |  2 +-
 include/linux/mmzone.h                             |  2 +-
 mm/filemap.c                                       |  4 ++--
 mm/memcontrol.c                                    |  2 +-
 mm/rmap.c                                          |  2 +-
 mm/vmscan.c                                        | 12 ++++++++----
 10 files changed, 30 insertions(+), 41 deletions(-)

diff --git a/Documentation/admin-guide/cgroup-v1/memcg_test.rst b/Documentation/admin-guide/cgroup-v1/memcg_test.rst
index 3f7115e07b5d..0b9f91589d3d 100644
--- a/Documentation/admin-guide/cgroup-v1/memcg_test.rst
+++ b/Documentation/admin-guide/cgroup-v1/memcg_test.rst
@@ -133,18 +133,9 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y.
 
 8. LRU
 ======
-        Each memcg has its own private LRU. Now, its handling is under global
-	VM's control (means that it's handled under global pgdat->lru_lock).
-	Almost all routines around memcg's LRU is called by global LRU's
-	list management functions under pgdat->lru_lock.
-
-	A special function is mem_cgroup_isolate_pages(). This scans
-	memcg's private LRU and call __isolate_lru_page() to extract a page
-	from LRU.
-
-	(By __isolate_lru_page(), the page is removed from both of global and
-	private LRU.)
-
+	Each memcg has its own vector of LRUs (inactive anon, active anon,
+	inactive file, active file, unevictable) of pages from each node,
+	each LRU handled under a single lru_lock for that memcg and node.
 
 9. Typical Tests.
 =================
diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst
index 0ae4f564c2d6..5a68ecfdb835 100644
--- a/Documentation/admin-guide/cgroup-v1/memory.rst
+++ b/Documentation/admin-guide/cgroup-v1/memory.rst
@@ -297,13 +297,13 @@ When oom event notifier is registered, event will be delivered.
 
    PG_locked.
      mm->page_table_lock
-         pgdat->lru_lock
-	   lock_page_cgroup.
+       lruvec->lru_lock
+	 lock_page_cgroup.
 
   In many cases, just lock_page_cgroup() is called.
 
-  per-zone-per-cgroup LRU (cgroup's private LRU) is just guarded by
-  pgdat->lru_lock, it has no lock of its own.
+  per-node-per-cgroup LRU (cgroup's private LRU) is just guarded by
+  lruvec->lru_lock, it has no lock of its own.
 
 2.7 Kernel Memory Extension (CONFIG_MEMCG_KMEM)
 -----------------------------------------------
diff --git a/Documentation/trace/events-kmem.rst b/Documentation/trace/events-kmem.rst
index 555484110e36..68fa75247488 100644
--- a/Documentation/trace/events-kmem.rst
+++ b/Documentation/trace/events-kmem.rst
@@ -69,7 +69,7 @@ When pages are freed in batch, the also mm_page_free_batched is triggered.
 Broadly speaking, pages are taken off the LRU lock in bulk and
 freed in batch with a page list. Significant amounts of activity here could
 indicate that the system is under memory pressure and can also indicate
-contention on the zone->lru_lock.
+contention on the lruvec->lru_lock.
 
 4. Per-CPU Allocator Activity
 =============================
diff --git a/Documentation/vm/unevictable-lru.rst b/Documentation/vm/unevictable-lru.rst
index 17d0861b0f1d..0e1490524f53 100644
--- a/Documentation/vm/unevictable-lru.rst
+++ b/Documentation/vm/unevictable-lru.rst
@@ -33,7 +33,7 @@ reclaim in Linux.  The problems have been observed at customer sites on large
 memory x86_64 systems.
 
 To illustrate this with an example, a non-NUMA x86_64 platform with 128GB of
-main memory will have over 32 million 4k pages in a single zone.  When a large
+main memory will have over 32 million 4k pages in a single node.  When a large
 fraction of these pages are not evictable for any reason [see below], vmscan
 will spend a lot of time scanning the LRU lists looking for the small fraction
 of pages that are evictable.  This can result in a situation where all CPUs are
@@ -55,7 +55,7 @@ unevictable, either by definition or by circumstance, in the future.
 The Unevictable Page List
 -------------------------
 
-The Unevictable LRU infrastructure consists of an additional, per-zone, LRU list
+The Unevictable LRU infrastructure consists of an additional, per-node, LRU list
 called the "unevictable" list and an associated page flag, PG_unevictable, to
 indicate that the page is being managed on the unevictable list.
 
@@ -84,15 +84,9 @@ The unevictable list does not differentiate between file-backed and anonymous,
 swap-backed pages.  This differentiation is only important while the pages are,
 in fact, evictable.
 
-The unevictable list benefits from the "arrayification" of the per-zone LRU
+The unevictable list benefits from the "arrayification" of the per-node LRU
 lists and statistics originally proposed and posted by Christoph Lameter.
 
-The unevictable list does not use the LRU pagevec mechanism. Rather,
-unevictable pages are placed directly on the page's zone's unevictable list
-under the zone lru_lock.  This allows us to prevent the stranding of pages on
-the unevictable list when one task has the page isolated from the LRU and other
-tasks are changing the "evictability" state of the page.
-
 
 Memory Control Group Interaction
 --------------------------------
@@ -101,8 +95,8 @@ The unevictable LRU facility interacts with the memory control group [aka
 memory controller; see Documentation/admin-guide/cgroup-v1/memory.rst] by extending the
 lru_list enum.
 
-The memory controller data structure automatically gets a per-zone unevictable
-list as a result of the "arrayification" of the per-zone LRU lists (one per
+The memory controller data structure automatically gets a per-node unevictable
+list as a result of the "arrayification" of the per-node LRU lists (one per
 lru_list enum element).  The memory controller tracks the movement of pages to
 and from the unevictable list.
 
@@ -196,7 +190,7 @@ for the sake of expediency, to leave a unevictable page on one of the regular
 active/inactive LRU lists for vmscan to deal with.  vmscan checks for such
 pages in all of the shrink_{active|inactive|page}_list() functions and will
 "cull" such pages that it encounters: that is, it diverts those pages to the
-unevictable list for the zone being scanned.
+unevictable list for the node being scanned.
 
 There may be situations where a page is mapped into a VM_LOCKED VMA, but the
 page is not marked as PG_mlocked.  Such pages will make it all the way to
@@ -328,7 +322,7 @@ If the page was NOT already mlocked, mlock_vma_page() attempts to isolate the
 page from the LRU, as it is likely on the appropriate active or inactive list
 at that time.  If the isolate_lru_page() succeeds, mlock_vma_page() will put
 back the page - by calling putback_lru_page() - which will notice that the page
-is now mlocked and divert the page to the zone's unevictable list.  If
+is now mlocked and divert the page to the node's unevictable list.  If
 mlock_vma_page() is unable to isolate the page from the LRU, vmscan will handle
 it later if and when it attempts to reclaim the page.
 
@@ -603,7 +597,7 @@ Some examples of these unevictable pages on the LRU lists are:
      unevictable list in mlock_vma_page().
 
 shrink_inactive_list() also diverts any unevictable pages that it finds on the
-inactive lists to the appropriate zone's unevictable list.
+inactive lists to the appropriate node's unevictable list.
 
 shrink_inactive_list() should only see SHM_LOCK'd pages that became SHM_LOCK'd
 after shrink_active_list() had moved them to the inactive list, or pages mapped
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index c28911c3afa8..852b8ee0da5d 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -78,7 +78,7 @@ struct page {
 		struct {	/* Page cache and anonymous pages */
 			/**
 			 * @lru: Pageout list, eg. active_list protected by
-			 * pgdat->lru_lock.  Sometimes used as a generic list
+			 * lruvec->lru_lock.  Sometimes used as a generic list
 			 * by the page owner.
 			 */
 			struct list_head lru;
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index f1ff6713ac06..bc91d4a43960 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -159,7 +159,7 @@ static inline bool free_area_empty(struct free_area *area, int migratetype)
 struct pglist_data;
 
 /*
- * zone->lock and the zone lru_lock are two of the hottest locks in the kernel.
+ * zone->lock and the lru_lock are two of the hottest locks in the kernel.
  * So add a wild amount of padding here to ensure that they fall into separate
  * cachelines.  There are very few zone structures in the machine, so space
  * consumption is not a concern here.
diff --git a/mm/filemap.c b/mm/filemap.c
index 1784478270e1..28fff98f4459 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -101,8 +101,8 @@
  *    ->swap_lock		(try_to_unmap_one)
  *    ->private_lock		(try_to_unmap_one)
  *    ->i_pages lock		(try_to_unmap_one)
- *    ->pgdat->lru_lock		(follow_page->mark_page_accessed)
- *    ->pgdat->lru_lock		(check_pte_range->isolate_lru_page)
+ *    ->lruvec->lru_lock	(follow_page->mark_page_accessed)
+ *    ->lruvec->lru_lock	(check_pte_range->isolate_lru_page)
  *    ->private_lock		(page_remove_rmap->set_page_dirty)
  *    ->i_pages lock		(page_remove_rmap->set_page_dirty)
  *    bdi.wb->list_lock		(page_remove_rmap->set_page_dirty)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b0c156da60fe..099926efbb48 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2940,7 +2940,7 @@ void __memcg_kmem_uncharge(struct page *page, int order)
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 
 /*
- * Because tail pages are not marked as "used", set it. We're under
+ * Because tail pages are not marked as "used", set it. Don't need
  * lruvec->lru_lock and migration entries setup in all page mappings.
  */
 void mem_cgroup_split_huge_fixup(struct page *head)
diff --git a/mm/rmap.c b/mm/rmap.c
index b3e381919835..39052794cb46 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -27,7 +27,7 @@
  *         mapping->i_mmap_rwsem
  *           anon_vma->rwsem
  *             mm->page_table_lock or pte_lock
- *               pgdat->lru_lock (in mark_page_accessed, isolate_lru_page)
+ *               lruvec->lru_lock (in mark_page_accessed, isolate_lru_page)
  *               swap_lock (in swap_duplicate, swap_info_get)
  *                 mmlist_lock (in mmput, drain_mmlist and others)
  *                 mapping->private_lock (in __set_page_dirty_buffers)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index de925bd629eb..2c98352c95cc 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1601,14 +1601,16 @@ static __always_inline void update_lru_sizes(struct lruvec *lruvec,
 }
 
 /**
- * pgdat->lru_lock is heavily contended.  Some of the functions that
+ * Isolating page from the lruvec to fill in @dst list by nr_to_scan times.
+ *
+ * lruvec->lru_lock is heavily contended.  Some of the functions that
  * shrink the lists perform better by taking out a batch of pages
  * and working on them outside the LRU lock.
  *
  * For pagecache intensive workloads, this function is the hottest
  * spot in the kernel (apart from copy_*_user functions).
  *
- * Appropriate locks must be held before calling this function.
+ * Lru_lock must be held before calling this function.
  *
  * @nr_to_scan:	The number of eligible pages to look through on the list.
  * @lruvec:	The LRU vector to pull pages from.
@@ -1809,14 +1811,16 @@ static int too_many_isolated(struct pglist_data *pgdat, int file,
 
 /*
  * This moves pages from @list to corresponding LRU list.
+ * The pages from @list is out of any lruvec, and in the end list reuses as
+ * pages_to_free list.
  *
  * We move them the other way if the page is referenced by one or more
  * processes, from rmap.
  *
  * If the pages are mostly unmapped, the processing is fast and it is
- * appropriate to hold zone_lru_lock across the whole operation.  But if
+ * appropriate to hold lru_lock across the whole operation.  But if
  * the pages are mapped, the processing is slow (page_referenced()) so we
- * should drop zone_lru_lock around each page.  It's impossible to balance
+ * should drop lru_lock around each page.  It's impossible to balance
  * this, so instead we remove the pages from the LRU while processing them.
  * It is safe to rely on PG_active against the non-LRU pages in here because
  * nobody will play with that bit on a non-LRU page.
-- 
1.8.3.1

[PATCH v9 18/20] mm/lru: revise the comments of lru_lock

[Alex Shi]

From: Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>

Since we changed the pgdat->lru_lock to lruvec->lru_lock, it's time to
fix the incorrect comments in code. Also fixed some zone->lru_lock comment
error from ancient time. etc.

Signed-off-by: Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
Cc: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Andrey Ryabinin <aryabinin-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org>
Cc: Jann Horn <jannh-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Mel Gorman <mgorman-3eNAlZScCAx27rWaFMvyedHuzzzSOjJt@public.gmane.org>
Cc: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
Cc: Matthew Wilcox <willy-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Cc: Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
---
 Documentation/admin-guide/cgroup-v1/memcg_test.rst | 15 +++------------
 Documentation/admin-guide/cgroup-v1/memory.rst     |  8 ++++----
 Documentation/trace/events-kmem.rst                |  2 +-
 Documentation/vm/unevictable-lru.rst               | 22 ++++++++--------------
 include/linux/mm_types.h                           |  2 +-
 include/linux/mmzone.h                             |  2 +-
 mm/filemap.c                                       |  4 ++--
 mm/memcontrol.c                                    |  2 +-
 mm/rmap.c                                          |  2 +-
 mm/vmscan.c                                        | 12 ++++++++----
 10 files changed, 30 insertions(+), 41 deletions(-)

diff --git a/Documentation/admin-guide/cgroup-v1/memcg_test.rst b/Documentation/admin-guide/cgroup-v1/memcg_test.rst
index 3f7115e07b5d..0b9f91589d3d 100644
--- a/Documentation/admin-guide/cgroup-v1/memcg_test.rst
+++ b/Documentation/admin-guide/cgroup-v1/memcg_test.rst
@@ -133,18 +133,9 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y.
 
 8. LRU
 ======
-        Each memcg has its own private LRU. Now, its handling is under global
-	VM's control (means that it's handled under global pgdat->lru_lock).
-	Almost all routines around memcg's LRU is called by global LRU's
-	list management functions under pgdat->lru_lock.
-
-	A special function is mem_cgroup_isolate_pages(). This scans
-	memcg's private LRU and call __isolate_lru_page() to extract a page
-	from LRU.
-
-	(By __isolate_lru_page(), the page is removed from both of global and
-	private LRU.)
-
+	Each memcg has its own vector of LRUs (inactive anon, active anon,
+	inactive file, active file, unevictable) of pages from each node,
+	each LRU handled under a single lru_lock for that memcg and node.
 
 9. Typical Tests.
 =================
diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst
index 0ae4f564c2d6..5a68ecfdb835 100644
--- a/Documentation/admin-guide/cgroup-v1/memory.rst
+++ b/Documentation/admin-guide/cgroup-v1/memory.rst
@@ -297,13 +297,13 @@ When oom event notifier is registered, event will be delivered.
 
    PG_locked.
      mm->page_table_lock
-         pgdat->lru_lock
-	   lock_page_cgroup.
+       lruvec->lru_lock
+	 lock_page_cgroup.
 
   In many cases, just lock_page_cgroup() is called.
 
-  per-zone-per-cgroup LRU (cgroup's private LRU) is just guarded by
-  pgdat->lru_lock, it has no lock of its own.
+  per-node-per-cgroup LRU (cgroup's private LRU) is just guarded by
+  lruvec->lru_lock, it has no lock of its own.
 
 2.7 Kernel Memory Extension (CONFIG_MEMCG_KMEM)
 -----------------------------------------------
diff --git a/Documentation/trace/events-kmem.rst b/Documentation/trace/events-kmem.rst
index 555484110e36..68fa75247488 100644
--- a/Documentation/trace/events-kmem.rst
+++ b/Documentation/trace/events-kmem.rst
@@ -69,7 +69,7 @@ When pages are freed in batch, the also mm_page_free_batched is triggered.
 Broadly speaking, pages are taken off the LRU lock in bulk and
 freed in batch with a page list. Significant amounts of activity here could
 indicate that the system is under memory pressure and can also indicate
-contention on the zone->lru_lock.
+contention on the lruvec->lru_lock.
 
 4. Per-CPU Allocator Activity
 =============================
diff --git a/Documentation/vm/unevictable-lru.rst b/Documentation/vm/unevictable-lru.rst
index 17d0861b0f1d..0e1490524f53 100644
--- a/Documentation/vm/unevictable-lru.rst
+++ b/Documentation/vm/unevictable-lru.rst
@@ -33,7 +33,7 @@ reclaim in Linux.  The problems have been observed at customer sites on large
 memory x86_64 systems.
 
 To illustrate this with an example, a non-NUMA x86_64 platform with 128GB of
-main memory will have over 32 million 4k pages in a single zone.  When a large
+main memory will have over 32 million 4k pages in a single node.  When a large
 fraction of these pages are not evictable for any reason [see below], vmscan
 will spend a lot of time scanning the LRU lists looking for the small fraction
 of pages that are evictable.  This can result in a situation where all CPUs are
@@ -55,7 +55,7 @@ unevictable, either by definition or by circumstance, in the future.
 The Unevictable Page List
 -------------------------
 
-The Unevictable LRU infrastructure consists of an additional, per-zone, LRU list
+The Unevictable LRU infrastructure consists of an additional, per-node, LRU list
 called the "unevictable" list and an associated page flag, PG_unevictable, to
 indicate that the page is being managed on the unevictable list.
 
@@ -84,15 +84,9 @@ The unevictable list does not differentiate between file-backed and anonymous,
 swap-backed pages.  This differentiation is only important while the pages are,
 in fact, evictable.
 
-The unevictable list benefits from the "arrayification" of the per-zone LRU
+The unevictable list benefits from the "arrayification" of the per-node LRU
 lists and statistics originally proposed and posted by Christoph Lameter.
 
-The unevictable list does not use the LRU pagevec mechanism. Rather,
-unevictable pages are placed directly on the page's zone's unevictable list
-under the zone lru_lock.  This allows us to prevent the stranding of pages on
-the unevictable list when one task has the page isolated from the LRU and other
-tasks are changing the "evictability" state of the page.
-
 
 Memory Control Group Interaction
 --------------------------------
@@ -101,8 +95,8 @@ The unevictable LRU facility interacts with the memory control group [aka
 memory controller; see Documentation/admin-guide/cgroup-v1/memory.rst] by extending the
 lru_list enum.
 
-The memory controller data structure automatically gets a per-zone unevictable
-list as a result of the "arrayification" of the per-zone LRU lists (one per
+The memory controller data structure automatically gets a per-node unevictable
+list as a result of the "arrayification" of the per-node LRU lists (one per
 lru_list enum element).  The memory controller tracks the movement of pages to
 and from the unevictable list.
 
@@ -196,7 +190,7 @@ for the sake of expediency, to leave a unevictable page on one of the regular
 active/inactive LRU lists for vmscan to deal with.  vmscan checks for such
 pages in all of the shrink_{active|inactive|page}_list() functions and will
 "cull" such pages that it encounters: that is, it diverts those pages to the
-unevictable list for the zone being scanned.
+unevictable list for the node being scanned.
 
 There may be situations where a page is mapped into a VM_LOCKED VMA, but the
 page is not marked as PG_mlocked.  Such pages will make it all the way to
@@ -328,7 +322,7 @@ If the page was NOT already mlocked, mlock_vma_page() attempts to isolate the
 page from the LRU, as it is likely on the appropriate active or inactive list
 at that time.  If the isolate_lru_page() succeeds, mlock_vma_page() will put
 back the page - by calling putback_lru_page() - which will notice that the page
-is now mlocked and divert the page to the zone's unevictable list.  If
+is now mlocked and divert the page to the node's unevictable list.  If
 mlock_vma_page() is unable to isolate the page from the LRU, vmscan will handle
 it later if and when it attempts to reclaim the page.
 
@@ -603,7 +597,7 @@ Some examples of these unevictable pages on the LRU lists are:
      unevictable list in mlock_vma_page().
 
 shrink_inactive_list() also diverts any unevictable pages that it finds on the
-inactive lists to the appropriate zone's unevictable list.
+inactive lists to the appropriate node's unevictable list.
 
 shrink_inactive_list() should only see SHM_LOCK'd pages that became SHM_LOCK'd
 after shrink_active_list() had moved them to the inactive list, or pages mapped
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index c28911c3afa8..852b8ee0da5d 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -78,7 +78,7 @@ struct page {
 		struct {	/* Page cache and anonymous pages */
 			/**
 			 * @lru: Pageout list, eg. active_list protected by
-			 * pgdat->lru_lock.  Sometimes used as a generic list
+			 * lruvec->lru_lock.  Sometimes used as a generic list
 			 * by the page owner.
 			 */
 			struct list_head lru;
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index f1ff6713ac06..bc91d4a43960 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -159,7 +159,7 @@ static inline bool free_area_empty(struct free_area *area, int migratetype)
 struct pglist_data;
 
 /*
- * zone->lock and the zone lru_lock are two of the hottest locks in the kernel.
+ * zone->lock and the lru_lock are two of the hottest locks in the kernel.
  * So add a wild amount of padding here to ensure that they fall into separate
  * cachelines.  There are very few zone structures in the machine, so space
  * consumption is not a concern here.
diff --git a/mm/filemap.c b/mm/filemap.c
index 1784478270e1..28fff98f4459 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -101,8 +101,8 @@
  *    ->swap_lock		(try_to_unmap_one)
  *    ->private_lock		(try_to_unmap_one)
  *    ->i_pages lock		(try_to_unmap_one)
- *    ->pgdat->lru_lock		(follow_page->mark_page_accessed)
- *    ->pgdat->lru_lock		(check_pte_range->isolate_lru_page)
+ *    ->lruvec->lru_lock	(follow_page->mark_page_accessed)
+ *    ->lruvec->lru_lock	(check_pte_range->isolate_lru_page)
  *    ->private_lock		(page_remove_rmap->set_page_dirty)
  *    ->i_pages lock		(page_remove_rmap->set_page_dirty)
  *    bdi.wb->list_lock		(page_remove_rmap->set_page_dirty)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b0c156da60fe..099926efbb48 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2940,7 +2940,7 @@ void __memcg_kmem_uncharge(struct page *page, int order)
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 
 /*
- * Because tail pages are not marked as "used", set it. We're under
+ * Because tail pages are not marked as "used", set it. Don't need
  * lruvec->lru_lock and migration entries setup in all page mappings.
  */
 void mem_cgroup_split_huge_fixup(struct page *head)
diff --git a/mm/rmap.c b/mm/rmap.c
index b3e381919835..39052794cb46 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -27,7 +27,7 @@
  *         mapping->i_mmap_rwsem
  *           anon_vma->rwsem
  *             mm->page_table_lock or pte_lock
- *               pgdat->lru_lock (in mark_page_accessed, isolate_lru_page)
+ *               lruvec->lru_lock (in mark_page_accessed, isolate_lru_page)
  *               swap_lock (in swap_duplicate, swap_info_get)
  *                 mmlist_lock (in mmput, drain_mmlist and others)
  *                 mapping->private_lock (in __set_page_dirty_buffers)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index de925bd629eb..2c98352c95cc 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1601,14 +1601,16 @@ static __always_inline void update_lru_sizes(struct lruvec *lruvec,
 }
 
 /**
- * pgdat->lru_lock is heavily contended.  Some of the functions that
+ * Isolating page from the lruvec to fill in @dst list by nr_to_scan times.
+ *
+ * lruvec->lru_lock is heavily contended.  Some of the functions that
  * shrink the lists perform better by taking out a batch of pages
  * and working on them outside the LRU lock.
  *
  * For pagecache intensive workloads, this function is the hottest
  * spot in the kernel (apart from copy_*_user functions).
  *
- * Appropriate locks must be held before calling this function.
+ * Lru_lock must be held before calling this function.
  *
  * @nr_to_scan:	The number of eligible pages to look through on the list.
  * @lruvec:	The LRU vector to pull pages from.
@@ -1809,14 +1811,16 @@ static int too_many_isolated(struct pglist_data *pgdat, int file,
 
 /*
  * This moves pages from @list to corresponding LRU list.
+ * The pages from @list is out of any lruvec, and in the end list reuses as
+ * pages_to_free list.
  *
  * We move them the other way if the page is referenced by one or more
  * processes, from rmap.
  *
  * If the pages are mostly unmapped, the processing is fast and it is
- * appropriate to hold zone_lru_lock across the whole operation.  But if
+ * appropriate to hold lru_lock across the whole operation.  But if
  * the pages are mapped, the processing is slow (page_referenced()) so we
- * should drop zone_lru_lock around each page.  It's impossible to balance
+ * should drop lru_lock around each page.  It's impossible to balance
  * this, so instead we remove the pages from the LRU while processing them.
  * It is safe to rely on PG_active against the non-LRU pages in here because
  * nobody will play with that bit on a non-LRU page.
-- 
1.8.3.1

[PATCH v9 19/20] mm/lru: add debug checking for page memcg moving

[Alex Shi]

This debug patch could give some clues if there are sth out of
consideration.

Hugh Dickins reported a bug of this patch, Thanks!

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 include/linux/memcontrol.h |  6 ++++++
 mm/compaction.c            |  2 ++
 mm/memcontrol.c            | 15 +++++++++++++++
 3 files changed, 23 insertions(+)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index f60009580d2a..27c7bbe82125 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -431,6 +431,8 @@ struct lruvec *lock_page_lruvec_irqsave(struct page *page,
 void unlock_page_lruvec_irq(struct lruvec *lruvec);
 void unlock_page_lruvec_irqrestore(struct lruvec *lruvec, unsigned long flags);
 
+void lruvec_memcg_debug(struct lruvec *lruvec, struct page *page);
+
 static inline
 struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css){
 	return css ? container_of(css, struct mem_cgroup, css) : NULL;
@@ -1191,6 +1193,10 @@ static inline void count_memcg_page_event(struct page *page,
 void count_memcg_event_mm(struct mm_struct *mm, enum vm_event_item idx)
 {
 }
+
+static inline void lruvec_memcg_debug(struct lruvec *lruvec, struct page *page)
+{
+}
 #endif /* CONFIG_MEMCG */
 
 /* idx can be of type enum memcg_stat_item or node_stat_item */
diff --git a/mm/compaction.c b/mm/compaction.c
index 4a773f0ffedf..40c270bd5092 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -984,6 +984,8 @@ static bool too_many_isolated(pg_data_t *pgdat)
 			compact_lock_irqsave(&lruvec->lru_lock, &flags, cc);
 			locked_lruvec = lruvec;
 
+			lruvec_memcg_debug(lruvec, page);
+
 			/* Try get exclusive access under lock */
 			if (!skip_updated) {
 				skip_updated = true;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 099926efbb48..2d71e53ead88 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1240,6 +1240,19 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd
 	return lruvec;
 }
 
+void lruvec_memcg_debug(struct lruvec *lruvec, struct page *page)
+{
+#ifdef CONFIG_DEBUG_VM
+	if (mem_cgroup_disabled())
+		return;
+
+	if (!page->mem_cgroup)
+		VM_BUG_ON_PAGE(lruvec_memcg(lruvec) != root_mem_cgroup, page);
+	else
+		VM_BUG_ON_PAGE(lruvec_memcg(lruvec) != page->mem_cgroup, page);
+#endif
+}
+
 /* page must be isolated */
 struct lruvec *lock_page_lruvec_irq(struct page *page)
 {
@@ -1248,6 +1261,7 @@ struct lruvec *lock_page_lruvec_irq(struct page *page)
 	lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
 	spin_lock_irq(&lruvec->lru_lock);
 
+	lruvec_memcg_debug(lruvec, page);
 	return lruvec;
 }
 
@@ -1258,6 +1272,7 @@ struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags)
 	lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
 	spin_lock_irqsave(&lruvec->lru_lock, *flags);
 
+	lruvec_memcg_debug(lruvec, page);
 	return lruvec;
 }
 
-- 
1.8.3.1

[PATCH v9 20/20] mm/memcg: add debug checking in lock_page_memcg

[Alex Shi]

This extra irq disable/enable and BUG_ON checking costs 5% readtwice
performance on a 2 socket * 26 cores * HT box. So put it into
CONFIG_PROVE_LOCKING.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/memcontrol.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2d71e53ead88..8d7f6336f15c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2026,6 +2026,12 @@ struct mem_cgroup *lock_page_memcg(struct page *page)
 	if (unlikely(!memcg))
 		return NULL;
 
+#ifdef CONFIG_PROVE_LOCKING
+	local_irq_save(flags);
+	might_lock(&memcg->move_lock);
+	local_irq_restore(flags);
+#endif
+
 	if (atomic_read(&memcg->moving_account) <= 0)
 		return memcg;
 
-- 
1.8.3.1

Re: [PATCH v9 00/21] per lruvec lru_lock for memcg

[Andrew Morton]

On Mon,  2 Mar 2020 19:00:10 +0800 Alex Shi <alex.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org> wrote:

> Hi all,
> 
> This patchset mainly includes 3 parts:
> 1, some code cleanup and minimum optimization as a preparation.
> 2, use TestCleanPageLRU as page isolation's precondition
> 3, replace per node lru_lock with per memcg per node lru_lock
> 
> The keypoint of this patchset is moving lru_lock into lruvec, give a 
> lru_lock for each of lruvec, thus bring a lru_lock for each of memcg 
> per node. So on a large node machine, each of memcg don't suffer from
> per node pgdat->lru_lock waiting. They could go fast with their self
> lru_lock now.
> 
> Since lruvec belongs to each memcg, the critical point is to keep
> page's memcg stable, so we take PageLRU as its isolation's precondition.
> Thanks for Johannes Weiner help and suggestion!
> 
> Following Daniel Jordan's suggestion, I have run 208 'dd' with on 104
> containers on a 2s * 26cores * HT box with a modefied case:
>   https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/tree/case-lru-file-readtwice
> 
> With this patchset, the readtwice performance increased about 80%
> in concurrent containers.
> 
> Thanks Hugh Dickins and Konstantin Khlebnikov, they both brought this
> idea 8 years ago, and others who give comments as well: Daniel Jordan, 
> Mel Gorman, Shakeel Butt, Matthew Wilcox etc.
> 
> Thanks for Testing support from Intel 0day and Rong Chen, Fengguang Wu,
> and Yun Wang.

I'm not seeing a lot of evidence of review and test activity yet.  But
I think I'll grab patches 01-06 as they look like fairly
straightforward improvements.

Re: [PATCH v9 00/21] per lruvec lru_lock for memcg

[Alex Shi]

ÔÚ 2020/3/3 ÉÏÎç6:12, Andrew Morton дµÀ:
>> Thanks for Testing support from Intel 0day and Rong Chen, Fengguang Wu,
>> and Yun Wang.
> I'm not seeing a lot of evidence of review and test activity yet.  But
> I think I'll grab patches 01-06 as they look like fairly
> straightforward improvements.

cc Fengguang and Rong Chen

I did some local functional testing and kselftest, they all look fine. 0day only warn me if some case failed. Is it no news is good news? :)

Thanks
Alex

Re: [PATCH v9 00/21] per lruvec lru_lock for memcg

[Hugh Dickins]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 3492 bytes --]

On Tue, 3 Mar 2020, Alex Shi wrote:
> 在 2020/3/3 上午6:12, Andrew Morton 写道:
> >> Thanks for Testing support from Intel 0day and Rong Chen, Fengguang Wu,
> >> and Yun Wang.
> > I'm not seeing a lot of evidence of review and test activity yet.  But
> > I think I'll grab patches 01-06 as they look like fairly
> > straightforward improvements.
> 
> cc Fengguang and Rong Chen
> 
> I did some local functional testing and kselftest, they all look fine.
> 0day only warn me if some case failed. Is it no news is good news? :)

And now the bad news.

Andrew, please revert those six (or seven as they ended up in mmotm).
5.6-rc4-mm1 without them runs my tmpfs+loop+swapping+memcg+ksm kernel
build loads fine (did four hours just now), but 5.6-rc4-mm1 itself
crashed just after starting - seconds or minutes I didn't see,
but it did not complete an iteration.

I thought maybe those six would be harmless (though I've not looked
at them at all); but knew already that the full series is not good yet:
I gave it a try over 5.6-rc4 on Monday, and crashed very soon on simpler
testing, in different ways from what hits mmotm.

The first thing wrong with the full set was when I tried tmpfs+loop+
swapping kernel builds in "mem=700M cgroup_disabled=memory", of course
with CONFIG_DEBUG_LIST=y. That soon collapsed in a splurge of OOM kills
and list_del corruption messages: __list_del_entry_valid < list_del <
__page_cache_release < __put_page < put_page < __try_to_reclaim_swap <
free_swap_and_cache < shmem_free_swap < shmem_undo_range.

When I next tried with "mem=1G" and memcg enabled (but not being used),
that managed some iterations, no OOM kills, no list_del warnings (was
it swapping? perhaps, perhaps not, I was trying to go easy on it just
to see if "cgroup_disabled=memory" had been the problem); but when
rebooting after that, again list_del corruption messages and crash
(I didn't note them down).

So I didn't take much notice of what the mmotm crash backtrace showed
(but IIRC shmem and swap were in it).

Alex, I'm afraid you're focusing too much on performance results,
without doing the basic testing needed - I thought we had given you
some hints on the challenging areas (swapping, move_charge_at_immigrate,
page migration) when we attached a *correctly working* 5.3 version back
on 23rd August:

https://lore.kernel.org/linux-mm/alpine.LSU.2.11.1908231736001.16920@eggly.anvils/

(Correctly working, except missing two patches I'd mistakenly dropped
as unnecessary in earlier rebases: but our discussions with Johannes
later showed to be very necessary, though their races rarely seen.)

I have not had the time (and do not expect to have the time) to review
your series: maybe it's one or two small fixes away from being complete,
or maybe it's still fundamentally flawed, I do not know.  I had naively
hoped that you would help with a patchset that worked, rather than
cutting it down into something which does not.

Submitting your series to routine testing is much easier for me than
reviewing it: but then, yes, it's a pity that I don't find the time
to report the results on intervening versions, which also crashed.

What I have to do now, is set aside time today and tomorrow, to package
up the old scripts I use, describe them and their environment, and send
them to you (cc akpm in case I fall under a bus): so that you can
reproduce the crashes for yourself, and get to work on them.

Hugh

Re: [PATCH v9 02/20] mm/memcg: fold lock_page_lru into commit_charge

[Hillf Danton]

On Mon,  2 Mar 2020 19:00:12 +0800 Alex Shi wrote:
> 
> As Konstantin Khlebnikov mentioned:
> 
> 	Also I don't like these functions:
> 	- called lock/unlock but actually also isolates
> 	- used just once
> 	- pgdat evaluated twice
> 
> Cleanup and fold these functions into commit_charge. It also reduces
> lock time while lrucare && !PageLRU.
> 
> Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
> Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: cgroups@vger.kernel.org
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> ---
>  mm/memcontrol.c | 57 ++++++++++++++++++++-------------------------------------
>  1 file changed, 20 insertions(+), 37 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index d09776cd6e10..875e2aebcde7 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2572,41 +2572,11 @@ static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
>  	css_put_many(&memcg->css, nr_pages);
>  }
>  
> -static void lock_page_lru(struct page *page, int *isolated)
> -{
> -	pg_data_t *pgdat = page_pgdat(page);
> -
> -	spin_lock_irq(&pgdat->lru_lock);
> -	if (PageLRU(page)) {
> -		struct lruvec *lruvec;
> -
> -		lruvec = mem_cgroup_page_lruvec(page, pgdat);
> -		ClearPageLRU(page);
> -		del_page_from_lru_list(page, lruvec, page_lru(page));
> -		*isolated = 1;
> -	} else
> -		*isolated = 0;
> -}
> -
> -static void unlock_page_lru(struct page *page, int isolated)
> -{
> -	pg_data_t *pgdat = page_pgdat(page);
> -
> -	if (isolated) {
> -		struct lruvec *lruvec;
> -
> -		lruvec = mem_cgroup_page_lruvec(page, pgdat);
> -		VM_BUG_ON_PAGE(PageLRU(page), page);
> -		SetPageLRU(page);
> -		add_page_to_lru_list(page, lruvec, page_lru(page));
> -	}
> -	spin_unlock_irq(&pgdat->lru_lock);
> -}
> -
>  static void commit_charge(struct page *page, struct mem_cgroup *memcg,
>  			  bool lrucare)
>  {
> -	int isolated;
> +	struct lruvec *lruvec = NULL;
> +	pg_data_t *pgdat;
>  
>  	VM_BUG_ON_PAGE(page->mem_cgroup, page);
>  
> @@ -2614,9 +2584,17 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
>  	 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
>  	 * may already be on some other mem_cgroup's LRU.  Take care of it.
>  	 */
> -	if (lrucare)
> -		lock_page_lru(page, &isolated);
> -
> +	if (lrucare) {
> +		pgdat = page_pgdat(page);
> +		spin_lock_irq(&pgdat->lru_lock);
> +
> +		if (PageLRU(page)) {
> +			lruvec = mem_cgroup_page_lruvec(page, pgdat);
> +			ClearPageLRU(page);
> +			del_page_from_lru_list(page, lruvec, page_lru(page));
> +		} else
> +			spin_unlock_irq(&pgdat->lru_lock);
> +	}
>  	/*
>  	 * Nobody should be changing or seriously looking at
>  	 * page->mem_cgroup at this point:
> @@ -2633,8 +2611,13 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
>  	 */
>  	page->mem_cgroup = memcg;
>  
Well it is likely to update memcg for page without lru_lock held even if
more care is required, which is a change added in the current semantic and
worth a line of words in log.

> -	if (lrucare)
> -		unlock_page_lru(page, isolated);
> +	if (lrucare && lruvec) {
> +		lruvec = mem_cgroup_page_lruvec(page, pgdat);
> +		VM_BUG_ON_PAGE(PageLRU(page), page);
> +		SetPageLRU(page);
> +		add_page_to_lru_list(page, lruvec, page_lru(page));
> +		spin_unlock_irq(&pgdat->lru_lock);
> +	}
>  }
>  
>  #ifdef CONFIG_MEMCG_KMEM
> -- 
> 1.8.3.1
> 
> 

Re: [PATCH v9 02/20] mm/memcg: fold lock_page_lru into commit_charge

[Alex Shi]

在 2020/3/4 上午11:13, Hillf Danton 写道:
>>  	 * Nobody should be changing or seriously looking at
>>  	 * page->mem_cgroup at this point:
>> @@ -2633,8 +2611,13 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
>>  	 */
>>  	page->mem_cgroup = memcg;
>>  
> Well it is likely to update memcg for page without lru_lock held even if
> more care is required, which is a change added in the current semantic and
> worth a line of words in log.
> 

the lru_lock is guard for lru list, not for page->mem_cgroup, seem no need to highlight this point. Do we?

Thanks
Alex

Re: [PATCH v9 02/20] mm/memcg: fold lock_page_lru into commit_charge

[Alex Shi]

ÔÚ 2020/3/4 ÉÏÎç11:13, Hillf Danton дµÀ:
>>  	 * Nobody should be changing or seriously looking at
>>  	 * page->mem_cgroup at this point:
>> @@ -2633,8 +2611,13 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
>>  	 */
>>  	page->mem_cgroup = memcg;
>>  
> Well it is likely to update memcg for page without lru_lock held even if
> more care is required, which is a change added in the current semantic and
> worth a line of words in log.
> 

the lru_lock is guard for lru list, not for page->mem_cgroup, seem no need to highlight this point. Do we?

Thanks
Alex