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* [PATCH v14 00/20]  per memcg lru lock
@ 2020-07-03  5:07 Alex Shi
  2020-07-03  5:07 ` [PATCH v14 01/20] mm/vmscan: remove unnecessary lruvec adding Alex Shi
                   ` (19 more replies)
  0 siblings, 20 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

This is a new version which bases on v5.8-rc3.

Current lru_lock is one for each of node, pgdat->lru_lock, that guard for
lru lists, but now we had moved the lru lists into memcg for long time. Still
using per node lru_lock is clearly unscalable, pages on each of memcgs have
to compete each others for a whole lru_lock. This patchset try to use per
lruvec/memcg lru_lock to repleace per node lru lock to guard lru lists, make
it scalable for memcgs and get performance gain.

Currently lru_lock still guards both lru list and page's lru bit, that's ok.
but if we want to use specific lruvec lock on the page, we need to pin down
the page's lruvec/memcg during locking. Just taking lruvec lock first may be
undermined by the page's memcg charge/migration. To fix this problem, we could
take out the page's lru bit clear and use it as pin down action to block the
memcg changes. That's the reason for atomic func TestClearPageLRU.
So now isolating a page need both actions: TestClearPageLRU and hold the
lru_lock.

The typic using for this is isolate_migratepages_block() in compaction.c
we have to take lru bit before lru lock, that serialized the page isolation
in memcg page charge/migration which will change page's lruvec and new 
lru_lock in it.

The above solution suggested by Johannes Weiner, and based on his new memcg 
charge path, we have this patchset. (Hugh Dickins tested and contributed much
code from compaction fix to general code polish, thanks a lot!).

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

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. Hugh Dickins also shared his kbuild-swap case. Thanks!

Alex Shi (18):
  mm/vmscan: remove unnecessary lruvec adding
  mm/page_idle: no unlikely double check for idle page counting
  mm/compaction: correct the comments of compact_defer_shift
  mm/compaction: rename compact_deferred as compact_should_defer
  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/memcg: add debug checking in lock_page_memcg
  mm/swap: fold vm event PGROTATED into pagevec_move_tail_fn
  mm/lru: move lru_lock holding in func lru_note_cost_page
  mm/lru: move lock into lru_note_cost
  mm/lru: introduce TestClearPageLRU
  mm/compaction: do page isolation first in compaction
  mm/mlock: reorder isolation sequence during munlock
  mm/swap: serialize memcg changes during pagevec_lru_move_fn
  mm/lru: replace pgdat lru_lock with lruvec lock
  mm/lru: introduce the relock_page_lruvec function
  mm/pgdat: remove pgdat lru_lock

Hugh Dickins (2):
  mm/vmscan: use relock for move_pages_to_lru
  mm/lru: revise the comments of lru_lock

 Documentation/admin-guide/cgroup-v1/memcg_test.rst |  15 +-
 Documentation/admin-guide/cgroup-v1/memory.rst     |  21 ++-
 Documentation/trace/events-kmem.rst                |   2 +-
 Documentation/vm/unevictable-lru.rst               |  22 +--
 include/linux/compaction.h                         |   4 +-
 include/linux/memcontrol.h                         |  98 ++++++++++++
 include/linux/mm_types.h                           |   2 +-
 include/linux/mmzone.h                             |   6 +-
 include/linux/page-flags.h                         |   1 +
 include/linux/swap.h                               |   4 +-
 include/trace/events/compaction.h                  |   2 +-
 mm/compaction.c                                    | 113 +++++++++----
 mm/filemap.c                                       |   4 +-
 mm/huge_memory.c                                   |  53 ++++--
 mm/memcontrol.c                                    |  71 ++++++++-
 mm/memory.c                                        |   3 -
 mm/mlock.c                                         |  93 +++++------
 mm/mmzone.c                                        |   1 +
 mm/page_alloc.c                                    |   1 -
 mm/page_idle.c                                     |   8 -
 mm/rmap.c                                          |   4 +-
 mm/swap.c                                          | 177 +++++++--------------
 mm/swap_state.c                                    |   2 -
 mm/vmscan.c                                        | 174 ++++++++++----------
 mm/workingset.c                                    |   2 -
 25 files changed, 518 insertions(+), 365 deletions(-)

-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 01/20] mm/vmscan: remove unnecessary lruvec adding
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 02/20] mm/page_idle: no unlikely double check for idle page counting Alex Shi
                   ` (18 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

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

[akpm@linux-foundation.org: coding style fixes]
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 | 37 ++++++++++++++++++++++++-------------
 1 file changed, 24 insertions(+), 13 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 749d239c62b2..ddb29d813d77 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1856,26 +1856,29 @@ 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);
@@ -1883,11 +1886,19 @@ 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;
-			if (PageActive(page))
-				workingset_age_nonresident(lruvec, 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;
+		if (PageActive(page))
+			workingset_age_nonresident(lruvec, nr_pages);
 	}
 
 	/*
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 02/20] mm/page_idle: no unlikely double check for idle page counting
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
  2020-07-03  5:07 ` [PATCH v14 01/20] mm/vmscan: remove unnecessary lruvec adding Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 03/20] mm/compaction: correct the comments of compact_defer_shift Alex Shi
                   ` (17 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

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 057c61df12db..5fdd753e151a 100644
--- a/mm/page_idle.c
+++ b/mm/page_idle.c
@@ -32,19 +32,11 @@
 static struct page *page_idle_get_page(unsigned long pfn)
 {
 	struct page *page = pfn_to_online_page(pfn);
-	pg_data_t *pgdat;
 
 	if (!page || !PageLRU(page) ||
 	    !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


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 03/20] mm/compaction: correct the comments of compact_defer_shift
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
  2020-07-03  5:07 ` [PATCH v14 01/20] mm/vmscan: remove unnecessary lruvec adding Alex Shi
  2020-07-03  5:07 ` [PATCH v14 02/20] mm/page_idle: no unlikely double check for idle page counting Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 04/20] mm/compaction: rename compact_deferred as compact_should_defer Alex Shi
                   ` (16 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

There is no compact_defer_limit. It should be compact_defer_shift in
use. and add compact_order_failed explanation.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 include/linux/mmzone.h | 1 +
 mm/compaction.c        | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index f6f884970511..14c668b7e793 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -512,6 +512,7 @@ struct zone {
 	 * On compaction failure, 1<<compact_defer_shift compactions
 	 * are skipped before trying again. The number attempted since
 	 * last failure is tracked with compact_considered.
+	 * compact_order_failed is the minimum compaction failed order.
 	 */
 	unsigned int		compact_considered;
 	unsigned int		compact_defer_shift;
diff --git a/mm/compaction.c b/mm/compaction.c
index 86375605faa9..cd1ef9e5e638 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -136,7 +136,7 @@ void __ClearPageMovable(struct page *page)
 
 /*
  * Compaction is deferred when compaction fails to result in a page
- * allocation success. 1 << compact_defer_limit compactions are skipped up
+ * allocation success. compact_defer_shift++, compactions are skipped up
  * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
  */
 void defer_compaction(struct zone *zone, int order)
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 04/20] mm/compaction: rename compact_deferred as compact_should_defer
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (2 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 03/20] mm/compaction: correct the comments of compact_defer_shift Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 05/20] mm/thp: move lru_add_page_tail func to huge_memory.c Alex Shi
                   ` (15 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

The compact_deferred is a defer suggestion check, deferring action does in
defer_compaction not here. so, better rename it to avoid confusing.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
---
 include/linux/compaction.h        | 4 ++--
 include/trace/events/compaction.h | 2 +-
 mm/compaction.c                   | 8 ++++----
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/linux/compaction.h b/include/linux/compaction.h
index 6fa0eea3f530..be9ed7437a38 100644
--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -100,7 +100,7 @@ extern enum compact_result compaction_suitable(struct zone *zone, int order,
 		unsigned int alloc_flags, int highest_zoneidx);
 
 extern void defer_compaction(struct zone *zone, int order);
-extern bool compaction_deferred(struct zone *zone, int order);
+extern bool compaction_should_defer(struct zone *zone, int order);
 extern void compaction_defer_reset(struct zone *zone, int order,
 				bool alloc_success);
 extern bool compaction_restarting(struct zone *zone, int order);
@@ -199,7 +199,7 @@ static inline void defer_compaction(struct zone *zone, int order)
 {
 }
 
-static inline bool compaction_deferred(struct zone *zone, int order)
+static inline bool compaction_should_defer(struct zone *zone, int order)
 {
 	return true;
 }
diff --git a/include/trace/events/compaction.h b/include/trace/events/compaction.h
index 54e5bf081171..33633c71df04 100644
--- a/include/trace/events/compaction.h
+++ b/include/trace/events/compaction.h
@@ -274,7 +274,7 @@
 		1UL << __entry->defer_shift)
 );
 
-DEFINE_EVENT(mm_compaction_defer_template, mm_compaction_deferred,
+DEFINE_EVENT(mm_compaction_defer_template, mm_compaction_should_defer,
 
 	TP_PROTO(struct zone *zone, int order),
 
diff --git a/mm/compaction.c b/mm/compaction.c
index cd1ef9e5e638..f14780fc296a 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -154,7 +154,7 @@ void defer_compaction(struct zone *zone, int order)
 }
 
 /* Returns true if compaction should be skipped this time */
-bool compaction_deferred(struct zone *zone, int order)
+bool compaction_should_defer(struct zone *zone, int order)
 {
 	unsigned long defer_limit = 1UL << zone->compact_defer_shift;
 
@@ -168,7 +168,7 @@ bool compaction_deferred(struct zone *zone, int order)
 	if (zone->compact_considered >= defer_limit)
 		return false;
 
-	trace_mm_compaction_deferred(zone, order);
+	trace_mm_compaction_should_defer(zone, order);
 
 	return true;
 }
@@ -2377,7 +2377,7 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
 		enum compact_result status;
 
 		if (prio > MIN_COMPACT_PRIORITY
-					&& compaction_deferred(zone, order)) {
+				&& compaction_should_defer(zone, order)) {
 			rc = max_t(enum compact_result, COMPACT_DEFERRED, rc);
 			continue;
 		}
@@ -2561,7 +2561,7 @@ static void kcompactd_do_work(pg_data_t *pgdat)
 		if (!populated_zone(zone))
 			continue;
 
-		if (compaction_deferred(zone, cc.order))
+		if (compaction_should_defer(zone, cc.order))
 			continue;
 
 		if (compaction_suitable(zone, cc.order, 0, zoneid) !=
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 05/20] mm/thp: move lru_add_page_tail func to huge_memory.c
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (3 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 04/20] mm/compaction: rename compact_deferred as compact_should_defer Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 06/20] mm/thp: clean up lru_add_page_tail Alex Shi
                   ` (14 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

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 THP. And make it static as Hugh Dickin suggested.

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 |  2 --
 mm/huge_memory.c     | 30 ++++++++++++++++++++++++++++++
 mm/swap.c            | 33 ---------------------------------
 3 files changed, 30 insertions(+), 35 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 5b3216ba39a9..2c29399b29a0 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -339,8 +339,6 @@ extern void lru_note_cost(struct lruvec *lruvec, bool file,
 			  unsigned int nr_pages);
 extern void lru_note_cost_page(struct page *);
 extern void lru_cache_add(struct 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 78c84bee7e29..9e050b13f597 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2340,6 +2340,36 @@ static void remap_page(struct page *page)
 	}
 }
 
+static void lru_add_page_tail(struct page *page, struct page *page_tail,
+				struct lruvec *lruvec, struct list_head *list)
+{
+	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));
+	}
+}
+
 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 a82efc33411f..7701d855873d 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -933,39 +933,6 @@ 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)
-{
-	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));
-	}
-}
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
-
 static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec,
 				 void *arg)
 {
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 06/20] mm/thp: clean up lru_add_page_tail
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (4 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 05/20] mm/thp: move lru_add_page_tail func to huge_memory.c Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 07/20] mm/thp: narrow lru locking Alex Shi
                   ` (13 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

Since the first parameter is only used by head page, it's better to make
it explicit.

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 | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 9e050b13f597..b18f21da4dac 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2340,19 +2340,19 @@ static void remap_page(struct page *page)
 	}
 }
 
-static void lru_add_page_tail(struct page *page, struct page *page_tail,
+static void lru_add_page_tail(struct page *head, struct page *page_tail,
 				struct lruvec *lruvec, struct list_head *list)
 {
-	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(!PageHead(head), head);
+	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);
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 07/20] mm/thp: narrow lru locking
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (5 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 06/20] mm/thp: clean up lru_add_page_tail Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-06  9:15   ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 08/20] mm/memcg: add debug checking in lock_page_memcg Alex Shi
                   ` (12 subsequent siblings)
  19 siblings, 1 reply; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

lru_lock and page cache xa_lock have no reason with current sequence,
put them together isn't necessary. let's narrow the lru locking, but
left the local_irq_disable to block interrupt re-entry and statistic update.

Hugh Dickins point: split_huge_page_to_list() was already silly,to be
using the _irqsave variant: it's just been taking sleeping locks, so
would already be broken if entered with interrupts enabled.
so we can save passing flags argument down to __split_huge_page().

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/huge_memory.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index b18f21da4dac..607869330329 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2433,7 +2433,7 @@ 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);
@@ -2442,8 +2442,6 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 	unsigned long offset = 0;
 	int i;
 
-	lruvec = mem_cgroup_page_lruvec(head, pgdat);
-
 	/* complete memcg works before add pages to LRU */
 	mem_cgroup_split_huge_fixup(head);
 
@@ -2455,6 +2453,11 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 		xa_lock(&swap_cache->i_pages);
 	}
 
+	/* lock lru list/PageCompound, ref freezed by page_ref_freeze */
+	spin_lock(&pgdat->lru_lock);
+
+	lruvec = mem_cgroup_page_lruvec(head, pgdat);
+
 	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 */
@@ -2474,6 +2477,8 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 	}
 
 	ClearPageCompound(head);
+	spin_unlock(&pgdat->lru_lock);
+	/* Caller disabled irqs, so they are still disabled here */
 
 	split_page_owner(head, HPAGE_PMD_ORDER);
 
@@ -2491,8 +2496,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 		page_ref_add(head, 2);
 		xa_unlock(&head->mapping->i_pages);
 	}
-
-	spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+	local_irq_enable();
 
 	remap_page(head);
 
@@ -2631,12 +2635,10 @@ 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;
-	unsigned long flags;
 	pgoff_t end;
 
 	VM_BUG_ON_PAGE(is_huge_zero_page(head), head);
@@ -2697,9 +2699,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 	unmap_page(head);
 	VM_BUG_ON_PAGE(compound_mapcount(head), head);
 
-	/* prevent PageLRU to go away from under us, and freeze lru stats */
-	spin_lock_irqsave(&pgdata->lru_lock, flags);
-
+	local_irq_disable();
 	if (mapping) {
 		XA_STATE(xas, &mapping->i_pages, page_index(head));
 
@@ -2729,7 +2729,7 @@ 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) };
 
@@ -2748,7 +2748,7 @@ 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);
+		local_irq_enable();
 		remap_page(head);
 		ret = -EBUSY;
 	}
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 08/20] mm/memcg: add debug checking in lock_page_memcg
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (6 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 07/20] mm/thp: narrow lru locking Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 09/20] mm/swap: fold vm event PGROTATED into pagevec_move_tail_fn Alex Shi
                   ` (11 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

Add a debug checking in lock_page_memcg, then we could get alarm
if anything wrong here.

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: 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 19622328e4b5..fde47272b13c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1983,6 +1983,12 @@ 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


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 09/20] mm/swap: fold vm event PGROTATED into pagevec_move_tail_fn
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (7 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 08/20] mm/memcg: add debug checking in lock_page_memcg Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 10/20] mm/lru: move lru_lock holding in func lru_note_cost_page Alex Shi
                   ` (10 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

Fold the PGROTATED event collection into pagevec_move_tail_fn call back
func like other funcs does in pagevec_lru_move_fn. Now all usage of
pagevec_lru_move_fn are same and no needs of the 3rd parameter.

It's simply the calling.

[lkp@intel.com: found a build issue in the original patch, thanks]
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/swap.c | 66 +++++++++++++++++++++++----------------------------------------
 1 file changed, 24 insertions(+), 42 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index 7701d855873d..dc8b02cdddcb 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -204,8 +204,7 @@ int get_kernel_page(unsigned long start, int write, struct page **pages)
 EXPORT_SYMBOL_GPL(get_kernel_page);
 
 static void pagevec_lru_move_fn(struct pagevec *pvec,
-	void (*move_fn)(struct page *page, struct lruvec *lruvec, void *arg),
-	void *arg)
+	void (*move_fn)(struct page *page, struct lruvec *lruvec))
 {
 	int i;
 	struct pglist_data *pgdat = NULL;
@@ -224,7 +223,7 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 		}
 
 		lruvec = mem_cgroup_page_lruvec(page, pgdat);
-		(*move_fn)(page, lruvec, arg);
+		(*move_fn)(page, lruvec);
 	}
 	if (pgdat)
 		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
@@ -232,35 +231,23 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 	pagevec_reinit(pvec);
 }
 
-static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec,
-				 void *arg)
+static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec)
 {
-	int *pgmoved = arg;
-
 	if (PageLRU(page) && !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));
-		(*pgmoved) += hpage_nr_pages(page);
+		__count_vm_events(PGROTATED, hpage_nr_pages(page));
 	}
 }
 
 /*
- * pagevec_move_tail() must be called with IRQ disabled.
- * Otherwise this may cause nasty races.
- */
-static void pagevec_move_tail(struct pagevec *pvec)
-{
-	int pgmoved = 0;
-
-	pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, &pgmoved);
-	__count_vm_events(PGROTATED, pgmoved);
-}
-
-/*
  * Writeback is about to end against a page which has been marked for immediate
  * reclaim.  If it still appears to be reclaimable, move it to the tail of the
  * inactive list.
+ *
+ * pagevec_move_tail_fn() must be called with IRQ disabled.
+ * Otherwise this may cause nasty races.
  */
 void rotate_reclaimable_page(struct page *page)
 {
@@ -273,7 +260,7 @@ void rotate_reclaimable_page(struct page *page)
 		local_lock_irqsave(&lru_rotate.lock, flags);
 		pvec = this_cpu_ptr(&lru_rotate.pvec);
 		if (!pagevec_add(pvec, page) || PageCompound(page))
-			pagevec_move_tail(pvec);
+			pagevec_lru_move_fn(pvec, pagevec_move_tail_fn);
 		local_unlock_irqrestore(&lru_rotate.lock, flags);
 	}
 }
@@ -315,8 +302,7 @@ void lru_note_cost_page(struct page *page)
 		      page_is_file_lru(page), hpage_nr_pages(page));
 }
 
-static void __activate_page(struct page *page, struct lruvec *lruvec,
-			    void *arg)
+static void __activate_page(struct page *page, struct lruvec *lruvec)
 {
 	if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
 		int lru = page_lru_base_type(page);
@@ -340,7 +326,7 @@ static void activate_page_drain(int cpu)
 	struct pagevec *pvec = &per_cpu(lru_pvecs.activate_page, cpu);
 
 	if (pagevec_count(pvec))
-		pagevec_lru_move_fn(pvec, __activate_page, NULL);
+		pagevec_lru_move_fn(pvec, __activate_page);
 }
 
 static bool need_activate_page_drain(int cpu)
@@ -358,7 +344,7 @@ void activate_page(struct page *page)
 		pvec = this_cpu_ptr(&lru_pvecs.activate_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);
 		local_unlock(&lru_pvecs.lock);
 	}
 }
@@ -374,7 +360,7 @@ void activate_page(struct page *page)
 
 	page = compound_head(page);
 	spin_lock_irq(&pgdat->lru_lock);
-	__activate_page(page, mem_cgroup_page_lruvec(page, pgdat), NULL);
+	__activate_page(page, mem_cgroup_page_lruvec(page, pgdat));
 	spin_unlock_irq(&pgdat->lru_lock);
 }
 #endif
@@ -526,8 +512,7 @@ void lru_cache_add_active_or_unevictable(struct page *page,
  * be write it out by flusher threads as this is much more effective
  * than the single-page writeout from reclaim.
  */
-static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec,
-			      void *arg)
+static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec)
 {
 	int lru;
 	bool active;
@@ -574,8 +559,7 @@ 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)
+static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec)
 {
 	if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) {
 		int lru = page_lru_base_type(page);
@@ -592,8 +576,7 @@ static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec,
 	}
 }
 
-static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec,
-			    void *arg)
+static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec)
 {
 	if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
 	    !PageSwapCache(page) && !PageUnevictable(page)) {
@@ -636,21 +619,21 @@ void lru_add_drain_cpu(int cpu)
 
 		/* No harm done if a racing interrupt already did this */
 		local_lock_irqsave(&lru_rotate.lock, flags);
-		pagevec_move_tail(pvec);
+		pagevec_lru_move_fn(pvec, pagevec_move_tail_fn);
 		local_unlock_irqrestore(&lru_rotate.lock, flags);
 	}
 
 	pvec = &per_cpu(lru_pvecs.lru_deactivate_file, cpu);
 	if (pagevec_count(pvec))
-		pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, NULL);
+		pagevec_lru_move_fn(pvec, lru_deactivate_file_fn);
 
 	pvec = &per_cpu(lru_pvecs.lru_deactivate, cpu);
 	if (pagevec_count(pvec))
-		pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
+		pagevec_lru_move_fn(pvec, lru_deactivate_fn);
 
 	pvec = &per_cpu(lru_pvecs.lru_lazyfree, cpu);
 	if (pagevec_count(pvec))
-		pagevec_lru_move_fn(pvec, lru_lazyfree_fn, NULL);
+		pagevec_lru_move_fn(pvec, lru_lazyfree_fn);
 
 	activate_page_drain(cpu);
 }
@@ -679,7 +662,7 @@ void deactivate_file_page(struct page *page)
 		pvec = this_cpu_ptr(&lru_pvecs.lru_deactivate_file);
 
 		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);
 		local_unlock(&lru_pvecs.lock);
 	}
 }
@@ -701,7 +684,7 @@ void deactivate_page(struct page *page)
 		pvec = this_cpu_ptr(&lru_pvecs.lru_deactivate);
 		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);
 		local_unlock(&lru_pvecs.lock);
 	}
 }
@@ -723,7 +706,7 @@ void mark_page_lazyfree(struct page *page)
 		pvec = this_cpu_ptr(&lru_pvecs.lru_lazyfree);
 		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);
 		local_unlock(&lru_pvecs.lock);
 	}
 }
@@ -933,8 +916,7 @@ void __pagevec_release(struct pagevec *pvec)
 }
 EXPORT_SYMBOL(__pagevec_release);
 
-static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec,
-				 void *arg)
+static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec)
 {
 	enum lru_list lru;
 	int was_unevictable = TestClearPageUnevictable(page);
@@ -993,7 +975,7 @@ 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);
 }
 
 /**
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 10/20] mm/lru: move lru_lock holding in func lru_note_cost_page
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (8 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 09/20] mm/swap: fold vm event PGROTATED into pagevec_move_tail_fn Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 11/20] mm/lru: move lock into lru_note_cost Alex Shi
                   ` (9 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

It's a clean up patch w/o function changes.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.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/memory.c     | 3 ---
 mm/swap.c       | 2 ++
 mm/swap_state.c | 2 --
 mm/workingset.c | 2 --
 4 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 87ec87cdc1ff..dafc5585517e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3150,10 +3150,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 				 * XXX: Move to lru_cache_add() when it
 				 * supports new vs putback
 				 */
-				spin_lock_irq(&page_pgdat(page)->lru_lock);
 				lru_note_cost_page(page);
-				spin_unlock_irq(&page_pgdat(page)->lru_lock);
-
 				lru_cache_add(page);
 				swap_readpage(page, true);
 			}
diff --git a/mm/swap.c b/mm/swap.c
index dc8b02cdddcb..b88ca630db70 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -298,8 +298,10 @@ void lru_note_cost(struct lruvec *lruvec, bool file, unsigned int nr_pages)
 
 void lru_note_cost_page(struct page *page)
 {
+	spin_lock_irq(&page_pgdat(page)->lru_lock);
 	lru_note_cost(mem_cgroup_page_lruvec(page, page_pgdat(page)),
 		      page_is_file_lru(page), hpage_nr_pages(page));
+	spin_unlock_irq(&page_pgdat(page)->lru_lock);
 }
 
 static void __activate_page(struct page *page, struct lruvec *lruvec)
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 05889e8e3c97..080be52db6a8 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -440,9 +440,7 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
 	}
 
 	/* XXX: Move to lru_cache_add() when it supports new vs putback */
-	spin_lock_irq(&page_pgdat(page)->lru_lock);
 	lru_note_cost_page(page);
-	spin_unlock_irq(&page_pgdat(page)->lru_lock);
 
 	/* Caller will initiate read into locked page */
 	SetPageWorkingset(page);
diff --git a/mm/workingset.c b/mm/workingset.c
index 50b7937bab32..337d5b9ad132 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -372,9 +372,7 @@ void workingset_refault(struct page *page, void *shadow)
 	if (workingset) {
 		SetPageWorkingset(page);
 		/* XXX: Move to lru_cache_add() when it supports new vs putback */
-		spin_lock_irq(&page_pgdat(page)->lru_lock);
 		lru_note_cost_page(page);
-		spin_unlock_irq(&page_pgdat(page)->lru_lock);
 		inc_lruvec_state(lruvec, WORKINGSET_RESTORE);
 	}
 out:
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 11/20] mm/lru: move lock into lru_note_cost
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (9 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 10/20] mm/lru: move lru_lock holding in func lru_note_cost_page Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 12/20] mm/lru: introduce TestClearPageLRU Alex Shi
                   ` (8 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

This patch move lru_lock into lru_note_cost. It's a bit ugly and may
cost more locking, but it's necessary for later per pgdat lru_lock to
per memcg lru_lock change.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.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/swap.c   | 5 +++--
 mm/vmscan.c | 4 +---
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index b88ca630db70..c67699de4869 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -269,7 +269,9 @@ void lru_note_cost(struct lruvec *lruvec, bool file, unsigned int nr_pages)
 {
 	do {
 		unsigned long lrusize;
+		pglist_data *pgdat = lruvec_pgdat(lruvec);
 
+		spin_lock_irq(&pgdat->lru_lock);
 		/* Record cost event */
 		if (file)
 			lruvec->file_cost += nr_pages;
@@ -293,15 +295,14 @@ void lru_note_cost(struct lruvec *lruvec, bool file, unsigned int nr_pages)
 			lruvec->file_cost /= 2;
 			lruvec->anon_cost /= 2;
 		}
+		spin_unlock_irq(&pgdat->lru_lock);
 	} while ((lruvec = parent_lruvec(lruvec)));
 }
 
 void lru_note_cost_page(struct page *page)
 {
-	spin_lock_irq(&page_pgdat(page)->lru_lock);
 	lru_note_cost(mem_cgroup_page_lruvec(page, page_pgdat(page)),
 		      page_is_file_lru(page), hpage_nr_pages(page));
-	spin_unlock_irq(&page_pgdat(page)->lru_lock);
 }
 
 static void __activate_page(struct page *page, struct lruvec *lruvec)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index ddb29d813d77..c1c4259b4de5 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1976,19 +1976,17 @@ static int current_may_throttle(void)
 				&stat, false);
 
 	spin_lock_irq(&pgdat->lru_lock);
-
 	move_pages_to_lru(lruvec, &page_list);
 
 	__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
-	lru_note_cost(lruvec, file, stat.nr_pageout);
 	item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT;
 	if (!cgroup_reclaim(sc))
 		__count_vm_events(item, nr_reclaimed);
 	__count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed);
 	__count_vm_events(PGSTEAL_ANON + file, nr_reclaimed);
-
 	spin_unlock_irq(&pgdat->lru_lock);
 
+	lru_note_cost(lruvec, file, stat.nr_pageout);
 	mem_cgroup_uncharge_list(&page_list);
 	free_unref_page_list(&page_list);
 
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 12/20] mm/lru: introduce TestClearPageLRU
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (10 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 11/20] mm/lru: move lock into lru_note_cost Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 13/20] mm/compaction: do page isolation first in compaction Alex Shi
                   ` (7 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

Combine PageLRU check and ClearPageLRU into a function by new
introduced func TestClearPageLRU. This function will be used as page
isolation precondition to prevent other isolations some where else.
Then there are may non PageLRU page on lru list, need to remove BUG
checking accordingly.

Hugh Dickins pointed that __page_cache_release and release_pages
has no need to do atomic clear bit since no user on the page at that
moment. and no need get_page() before lru bit clear in isolate_lru_page,
since it '(1) Must be called with an elevated refcount on the page'.

As Andrew Morton mentioned this change would dirty cacheline for page
isn't on LRU. But the lost would be acceptable with Rong Chen
<rong.a.chen@intel.com> report:
https://lkml.org/lkml/2020/3/4/173

Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.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/mlock.c                 |  3 +--
 mm/swap.c                  |  6 ++----
 mm/vmscan.c                | 26 +++++++++++---------------
 4 files changed, 15 insertions(+), 21 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 6be1aa559b1e..9554ed1387dc 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -326,6 +326,7 @@ 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/mlock.c b/mm/mlock.c
index f8736136fad7..228ba5a8e0a5 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 c67699de4869..b24d5f69b93a 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -83,10 +83,9 @@ static void __page_cache_release(struct page *page)
 		struct lruvec *lruvec;
 		unsigned long flags;
 
+		__ClearPageLRU(page);
 		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);
 	}
@@ -878,9 +877,8 @@ void release_pages(struct page **pages, int nr)
 				spin_lock_irqsave(&locked_pgdat->lru_lock, flags);
 			}
 
-			lruvec = mem_cgroup_page_lruvec(page, locked_pgdat);
-			VM_BUG_ON_PAGE(!PageLRU(page), page);
 			__ClearPageLRU(page);
+			lruvec = mem_cgroup_page_lruvec(page, locked_pgdat);
 			del_page_from_lru_list(page, lruvec, page_off_lru(page));
 		}
 
diff --git a/mm/vmscan.c b/mm/vmscan.c
index c1c4259b4de5..18986fefd49b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1548,16 +1548,16 @@ int __isolate_lru_page(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
@@ -1671,8 +1671,6 @@ 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;
 
@@ -1769,21 +1767,19 @@ 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)) {
+	if (TestClearPageLRU(page)) {
 		pg_data_t *pgdat = page_pgdat(page);
 		struct lruvec *lruvec;
+		int lru = page_lru(page);
 
-		spin_lock_irq(&pgdat->lru_lock);
+		get_page(page);
 		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;
 	}
+
 	return ret;
 }
 
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 13/20] mm/compaction: do page isolation first in compaction
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (11 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 12/20] mm/lru: introduce TestClearPageLRU Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 14/20] mm/mlock: reorder isolation sequence during munlock Alex Shi
                   ` (6 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

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.
With this patch, the compaction will only deal the PageLRU set and now
isolated pages to skip the just alloced page which no LRU bit. And the
isolation could exclusive the other isolations in memcg move_account,
page migrations and thp split_huge_page.

As a side effect, PageLRU may be cleared during shrink_inactive_list
path for isolation reason. If so, we can skip that page.

Hugh Dickins <hughd@google.com> fixed following bugs in this patch's
early version:

Fix lots of crashes under compaction load: isolate_migratepages_block()
must clean up appropriately when rejecting a page, setting PageLRU again
if it had been cleared; and a put_page() after get_page_unless_zero()
cannot safely be done while holding locked_lruvec - it may turn out to
be the final put_page(), which will take an lruvec lock when PageLRU.
And move __isolate_lru_page_prepare back after get_page_unless_zero to
make trylock_page() safe:
trylock_page() is not safe to use at this time: its setting PG_locked
can race with the page being freed or allocated ("Bad page"), and can
also erase flags being set by one of those "sole owners" of a freshly
allocated page who use non-atomic __SetPageFlag().

Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
---
 include/linux/swap.h |  2 +-
 mm/compaction.c      | 42 +++++++++++++++++++++++++++++++++---------
 mm/vmscan.c          | 38 ++++++++++++++++++++++----------------
 3 files changed, 56 insertions(+), 26 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 2c29399b29a0..6d23d3beeff7 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -358,7 +358,7 @@ 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 f14780fc296a..2da2933fe56b 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -869,6 +869,7 @@ static bool too_many_isolated(pg_data_t *pgdat)
 		if (!valid_page && IS_ALIGNED(low_pfn, pageblock_nr_pages)) {
 			if (!cc->ignore_skip_hint && get_pageblock_skip(page)) {
 				low_pfn = end_pfn;
+				page = NULL;
 				goto isolate_abort;
 			}
 			valid_page = page;
@@ -950,6 +951,21 @@ static bool too_many_isolated(pg_data_t *pgdat)
 		if (!(cc->gfp_mask & __GFP_FS) && page_mapping(page))
 			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;
+
+		if (__isolate_lru_page_prepare(page, isolate_mode) != 0)
+			goto isolate_fail_put;
+
+		/* Try isolate the page */
+		if (!TestClearPageLRU(page))
+			goto isolate_fail_put;
+
 		/* If we already hold the lock, we can skip some rechecking */
 		if (!locked) {
 			locked = compact_lock_irqsave(&pgdat->lru_lock,
@@ -962,10 +978,6 @@ 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
@@ -973,16 +985,13 @@ static bool too_many_isolated(pg_data_t *pgdat)
 			 */
 			if (unlikely(PageCompound(page) && !cc->alloc_contig)) {
 				low_pfn += compound_nr(page) - 1;
-				goto isolate_fail;
+				SetPageLRU(page);
+				goto isolate_fail_put;
 			}
 		}
 
 		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
-		/* Try isolate the page */
-		if (__isolate_lru_page(page, isolate_mode) != 0)
-			goto isolate_fail;
-
 		/* The whole page is taken off the LRU; skip the tail pages. */
 		if (PageCompound(page))
 			low_pfn += compound_nr(page) - 1;
@@ -1011,6 +1020,15 @@ static bool too_many_isolated(pg_data_t *pgdat)
 		}
 
 		continue;
+
+isolate_fail_put:
+		/* Avoid potential deadlock in freeing page under lru_lock */
+		if (locked) {
+			spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+			locked = false;
+		}
+		put_page(page);
+
 isolate_fail:
 		if (!skip_on_failure)
 			continue;
@@ -1047,9 +1065,15 @@ static bool too_many_isolated(pg_data_t *pgdat)
 	if (unlikely(low_pfn > end_pfn))
 		low_pfn = end_pfn;
 
+	page = NULL;
+
 isolate_abort:
 	if (locked)
 		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+	if (page) {
+		SetPageLRU(page);
+		put_page(page);
+	}
 
 	/*
 	 * Updated the cached scanner pfn once the pageblock has been scanned
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 18986fefd49b..f77748adc340 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1544,7 +1544,7 @@ unsigned int 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;
 
@@ -1598,20 +1598,9 @@ 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 sanity check.
@@ -1691,17 +1680,34 @@ 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


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 14/20] mm/mlock: reorder isolation sequence during munlock
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (12 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 13/20] mm/compaction: do page isolation first in compaction Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 15/20] mm/swap: serialize memcg changes during pagevec_lru_move_fn Alex Shi
                   ` (5 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

This patch reorder the isolation steps during munlock, move the lru lock
to guard each pages, unfold __munlock_isolate_lru_page func, to do the
preparation for lru lock change.

__split_huge_page_refcount doesn't exist, but we still have to guard
PageMlocked and PageLRU in __split_huge_page_tail, that is the reason
ClearPageLRU action is moved after lru locking.

[lkp@intel.com: found a sleeping function bug ... at mm/rmap.c]
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 | 93 ++++++++++++++++++++++++++++++++++----------------------------
 1 file changed, 51 insertions(+), 42 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c
index 228ba5a8e0a5..7098be122966 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()
@@ -181,6 +162,7 @@ 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 +171,42 @@ 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);
 	spin_lock_irq(&pgdat->lru_lock);
+	clearlru = TestClearPageLRU(page);
 
 	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;
 }
 
@@ -297,34 +289,51 @@ 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;
+		bool clearlru;
 
-		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 {
+		clearlru = TestClearPageLRU(page);
+		spin_lock_irq(&zone->zone_pgdat->lru_lock);
+
+		if (!TestClearPageMlocked(page)) {
 			delta_munlocked++;
+			if (clearlru)
+				SetPageLRU(page);
+			goto putback;
+		}
+
+		if (!clearlru) {
+			__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));
+		spin_unlock_irq(&zone->zone_pgdat->lru_lock);
+		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:
+		spin_unlock_irq(&zone->zone_pgdat->lru_lock);
 		pagevec_add(&pvec_putback, pvec->pages[i]);
 		pvec->pages[i] = NULL;
 	}
+	/* tempary disable irq, will remove later */
+	local_irq_disable();
 	__mod_zone_page_state(zone, NR_MLOCK, delta_munlocked);
-	spin_unlock_irq(&zone->zone_pgdat->lru_lock);
+	local_irq_enable();
 
 	/* Now we can release pins of pages that we are not munlocking */
 	pagevec_release(&pvec_putback);
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 15/20] mm/swap: serialize memcg changes during pagevec_lru_move_fn
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (13 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 14/20] mm/mlock: reorder isolation sequence during munlock Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  9:13   ` Konstantin Khlebnikov
  2020-07-03  5:07 ` [PATCH v14 16/20] mm/lru: replace pgdat lru_lock with lruvec lock Alex Shi
                   ` (4 subsequent siblings)
  19 siblings, 1 reply; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

Hugh Dickins' found a memcg change bug on original version:
If we want to change the pgdat->lru_lock to memcg's lruvec lock, we have
to serialize mem_cgroup_move_account during pagevec_lru_move_fn. The
possible bad scenario would like:

	cpu 0					cpu 1
lruvec = mem_cgroup_page_lruvec()
					if (!isolate_lru_page())
						mem_cgroup_move_account

spin_lock_irqsave(&lruvec->lru_lock <== wrong lock.

So we need the ClearPageLRU to block isolate_lru_page(), then serialize
the memcg change here.

Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 mm/swap.c | 31 +++++++++++++++++++------------
 1 file changed, 19 insertions(+), 12 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index b24d5f69b93a..55eb2c2eed03 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -203,7 +203,7 @@ int get_kernel_page(unsigned long start, int write, struct page **pages)
 EXPORT_SYMBOL_GPL(get_kernel_page);
 
 static void pagevec_lru_move_fn(struct pagevec *pvec,
-	void (*move_fn)(struct page *page, struct lruvec *lruvec))
+	void (*move_fn)(struct page *page, struct lruvec *lruvec), bool add)
 {
 	int i;
 	struct pglist_data *pgdat = NULL;
@@ -221,8 +221,15 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 			spin_lock_irqsave(&pgdat->lru_lock, flags);
 		}
 
+		/* new page add to lru or page moving between lru */
+		if (!add && !TestClearPageLRU(page))
+			continue;
+
 		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 		(*move_fn)(page, lruvec);
+
+		if (!add)
+			SetPageLRU(page);
 	}
 	if (pgdat)
 		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
@@ -259,7 +266,7 @@ void rotate_reclaimable_page(struct page *page)
 		local_lock_irqsave(&lru_rotate.lock, flags);
 		pvec = this_cpu_ptr(&lru_rotate.pvec);
 		if (!pagevec_add(pvec, page) || PageCompound(page))
-			pagevec_lru_move_fn(pvec, pagevec_move_tail_fn);
+			pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, false);
 		local_unlock_irqrestore(&lru_rotate.lock, flags);
 	}
 }
@@ -328,7 +335,7 @@ static void activate_page_drain(int cpu)
 	struct pagevec *pvec = &per_cpu(lru_pvecs.activate_page, cpu);
 
 	if (pagevec_count(pvec))
-		pagevec_lru_move_fn(pvec, __activate_page);
+		pagevec_lru_move_fn(pvec, __activate_page, false);
 }
 
 static bool need_activate_page_drain(int cpu)
@@ -346,7 +353,7 @@ void activate_page(struct page *page)
 		pvec = this_cpu_ptr(&lru_pvecs.activate_page);
 		get_page(page);
 		if (!pagevec_add(pvec, page) || PageCompound(page))
-			pagevec_lru_move_fn(pvec, __activate_page);
+			pagevec_lru_move_fn(pvec, __activate_page, false);
 		local_unlock(&lru_pvecs.lock);
 	}
 }
@@ -621,21 +628,21 @@ void lru_add_drain_cpu(int cpu)
 
 		/* No harm done if a racing interrupt already did this */
 		local_lock_irqsave(&lru_rotate.lock, flags);
-		pagevec_lru_move_fn(pvec, pagevec_move_tail_fn);
+		pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, false);
 		local_unlock_irqrestore(&lru_rotate.lock, flags);
 	}
 
 	pvec = &per_cpu(lru_pvecs.lru_deactivate_file, cpu);
 	if (pagevec_count(pvec))
-		pagevec_lru_move_fn(pvec, lru_deactivate_file_fn);
+		pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, false);
 
 	pvec = &per_cpu(lru_pvecs.lru_deactivate, cpu);
 	if (pagevec_count(pvec))
-		pagevec_lru_move_fn(pvec, lru_deactivate_fn);
+		pagevec_lru_move_fn(pvec, lru_deactivate_fn, false);
 
 	pvec = &per_cpu(lru_pvecs.lru_lazyfree, cpu);
 	if (pagevec_count(pvec))
-		pagevec_lru_move_fn(pvec, lru_lazyfree_fn);
+		pagevec_lru_move_fn(pvec, lru_lazyfree_fn, false);
 
 	activate_page_drain(cpu);
 }
@@ -664,7 +671,7 @@ void deactivate_file_page(struct page *page)
 		pvec = this_cpu_ptr(&lru_pvecs.lru_deactivate_file);
 
 		if (!pagevec_add(pvec, page) || PageCompound(page))
-			pagevec_lru_move_fn(pvec, lru_deactivate_file_fn);
+			pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, false);
 		local_unlock(&lru_pvecs.lock);
 	}
 }
@@ -686,7 +693,7 @@ void deactivate_page(struct page *page)
 		pvec = this_cpu_ptr(&lru_pvecs.lru_deactivate);
 		get_page(page);
 		if (!pagevec_add(pvec, page) || PageCompound(page))
-			pagevec_lru_move_fn(pvec, lru_deactivate_fn);
+			pagevec_lru_move_fn(pvec, lru_deactivate_fn, false);
 		local_unlock(&lru_pvecs.lock);
 	}
 }
@@ -708,7 +715,7 @@ void mark_page_lazyfree(struct page *page)
 		pvec = this_cpu_ptr(&lru_pvecs.lru_lazyfree);
 		get_page(page);
 		if (!pagevec_add(pvec, page) || PageCompound(page))
-			pagevec_lru_move_fn(pvec, lru_lazyfree_fn);
+			pagevec_lru_move_fn(pvec, lru_lazyfree_fn, false);
 		local_unlock(&lru_pvecs.lock);
 	}
 }
@@ -976,7 +983,7 @@ 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);
+	pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn, true);
 }
 
 /**
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 16/20] mm/lru: replace pgdat lru_lock with lruvec lock
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (14 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 15/20] mm/swap: serialize memcg changes during pagevec_lru_move_fn Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 17/20] mm/lru: introduce the relock_page_lruvec function Alex Shi
                   ` (3 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

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

After move memcg charge before lru inserting, page isolation could
stable page's memcg, then per memcg lruvec lock is stable and could
replace per node lru lock.

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.

Also add a debug func in locking which may give some clues if there are
sth out of hands.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.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: 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 | 98 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/mmzone.h     |  2 +
 mm/compaction.c            | 67 +++++++++++++++++++------------
 mm/huge_memory.c           |  9 ++---
 mm/memcontrol.c            | 63 ++++++++++++++++++++++++++++-
 mm/mlock.c                 | 32 +++++++--------
 mm/mmzone.c                |  1 +
 mm/swap.c                  | 79 +++++++++++++++++--------------------
 mm/vmscan.c                | 70 ++++++++++++++++++---------------
 9 files changed, 300 insertions(+), 121 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e77197a62809..6e670f991b42 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -411,6 +411,19 @@ 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(struct page *page);
+struct lruvec *lock_page_lruvec_irq(struct page *page);
+struct lruvec *lock_page_lruvec_irqsave(struct page *page,
+						unsigned long *flags);
+
+#ifdef CONFIG_DEBUG_VM
+void lruvec_memcg_debug(struct lruvec *lruvec, struct page *page);
+#else
+static inline void lruvec_memcg_debug(struct lruvec *lruvec, struct page *page)
+{
+}
+#endif
+
 static inline
 struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css){
 	return css ? container_of(css, struct mem_cgroup, css) : NULL;
@@ -892,6 +905,31 @@ static inline void mem_cgroup_put(struct mem_cgroup *memcg)
 {
 }
 
+static inline struct lruvec *lock_page_lruvec(struct page *page)
+{
+	struct pglist_data *pgdat = page_pgdat(page);
+
+	spin_lock(&pgdat->__lruvec.lru_lock);
+	return &pgdat->__lruvec;
+}
+
+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 struct mem_cgroup *
 mem_cgroup_iter(struct mem_cgroup *root,
 		struct mem_cgroup *prev,
@@ -1126,6 +1164,10 @@ 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 */
@@ -1255,6 +1297,62 @@ static inline struct lruvec *parent_lruvec(struct lruvec *lruvec)
 	return mem_cgroup_lruvec(memcg, lruvec_pgdat(lruvec));
 }
 
+static inline void unlock_page_lruvec(struct lruvec *lruvec)
+{
+	spin_unlock(&lruvec->lru_lock);
+}
+
+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);
+}
+
+/* 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);
+	bool locked;
+
+	rcu_read_lock();
+	locked = mem_cgroup_page_lruvec(page, pgdat) == locked_lruvec;
+	rcu_read_unlock();
+
+	if (locked)
+		return locked_lruvec;
+
+	if (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);
+	bool locked;
+
+	rcu_read_lock();
+	locked = mem_cgroup_page_lruvec(page, pgdat) == locked_lruvec;
+	rcu_read_unlock();
+
+	if (locked)
+		return locked_lruvec;
+
+	if (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/include/linux/mmzone.h b/include/linux/mmzone.h
index 14c668b7e793..36c1680efd90 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -261,6 +261,8 @@ struct lruvec {
 	atomic_long_t			nonresident_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 2da2933fe56b..88bbd2e93895 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -787,7 +787,7 @@ 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;
@@ -847,11 +847,21 @@ 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))
@@ -922,10 +932,9 @@ 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))
@@ -966,10 +975,20 @@ static bool too_many_isolated(pg_data_t *pgdat)
 		if (!TestClearPageLRU(page))
 			goto isolate_fail_put;
 
+		rcu_read_lock();
+		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);
+
+			compact_lock_irqsave(&lruvec->lru_lock, &flags, cc);
+			locked_lruvec = lruvec;
+			rcu_read_unlock();
+
+			lruvec_memcg_debug(lruvec, page);
 
 			/* Try get exclusive access under lock */
 			if (!skip_updated) {
@@ -988,9 +1007,8 @@ static bool too_many_isolated(pg_data_t *pgdat)
 				SetPageLRU(page);
 				goto isolate_fail_put;
 			}
-		}
-
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+		} else
+			rcu_read_unlock();
 
 		/* The whole page is taken off the LRU; skip the tail pages. */
 		if (PageCompound(page))
@@ -1023,9 +1041,9 @@ static bool too_many_isolated(pg_data_t *pgdat)
 
 isolate_fail_put:
 		/* Avoid potential deadlock in freeing page under lru_lock */
-		if (locked) {
-			spin_unlock_irqrestore(&pgdat->lru_lock, flags);
-			locked = false;
+		if (locked_lruvec) {
+			unlock_page_lruvec_irqrestore(locked_lruvec, flags);
+			locked_lruvec = NULL;
 		}
 		put_page(page);
 
@@ -1039,9 +1057,10 @@ 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;
@@ -1068,8 +1087,8 @@ static bool too_many_isolated(pg_data_t *pgdat)
 	page = NULL;
 
 isolate_abort:
-	if (locked)
-		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+	if (locked_lruvec)
+		unlock_page_lruvec_irqrestore(locked_lruvec, flags);
 	if (page) {
 		SetPageLRU(page);
 		put_page(page);
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 607869330329..2252d26b41af 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2346,7 +2346,7 @@ static void lru_add_page_tail(struct page *head, struct page *page_tail,
 	VM_BUG_ON_PAGE(!PageHead(head), head);
 	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);
@@ -2436,7 +2436,6 @@ 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;
@@ -2454,9 +2453,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 	}
 
 	/* lock lru list/PageCompound, ref freezed by page_ref_freeze */
-	spin_lock(&pgdat->lru_lock);
-
-	lruvec = mem_cgroup_page_lruvec(head, pgdat);
+	lruvec = lock_page_lruvec(head);
 
 	for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
 		__split_huge_page_tail(head, i, lruvec, list);
@@ -2477,7 +2474,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 	}
 
 	ClearPageCompound(head);
-	spin_unlock(&pgdat->lru_lock);
+	unlock_page_lruvec(lruvec);
 	/* Caller disabled irqs, so they are still disabled here */
 
 	split_page_owner(head, HPAGE_PMD_ORDER);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index fde47272b13c..d5e56be42f21 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1196,6 +1196,19 @@ int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
 	return ret;
 }
 
+#ifdef CONFIG_DEBUG_VM
+void lruvec_memcg_debug(struct lruvec *lruvec, struct page *page)
+{
+	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
+
 /**
  * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page
  * @page: the page
@@ -1215,7 +1228,8 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd
 		goto out;
 	}
 
-	memcg = page->mem_cgroup;
+	VM_BUG_ON_PAGE(PageTail(page), page);
+	memcg = READ_ONCE(page->mem_cgroup);
 	/*
 	 * Swapcache readahead pages are added to the LRU - and
 	 * possibly migrated - before they are charged.
@@ -1236,6 +1250,51 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd
 	return lruvec;
 }
 
+struct lruvec *lock_page_lruvec(struct page *page)
+{
+	struct lruvec *lruvec;
+	struct pglist_data *pgdat = page_pgdat(page);
+
+	rcu_read_lock();
+	lruvec = mem_cgroup_page_lruvec(page, pgdat);
+	spin_lock(&lruvec->lru_lock);
+	rcu_read_unlock();
+
+	lruvec_memcg_debug(lruvec, page);
+
+	return lruvec;
+}
+
+struct lruvec *lock_page_lruvec_irq(struct page *page)
+{
+	struct lruvec *lruvec;
+	struct pglist_data *pgdat = page_pgdat(page);
+
+	rcu_read_lock();
+	lruvec = mem_cgroup_page_lruvec(page, pgdat);
+	spin_lock_irq(&lruvec->lru_lock);
+	rcu_read_unlock();
+
+	lruvec_memcg_debug(lruvec, page);
+
+	return lruvec;
+}
+
+struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags)
+{
+	struct lruvec *lruvec;
+	struct pglist_data *pgdat = page_pgdat(page);
+
+	rcu_read_lock();
+	lruvec = mem_cgroup_page_lruvec(page, pgdat);
+	spin_lock_irqsave(&lruvec->lru_lock, *flags);
+	rcu_read_unlock();
+
+	lruvec_memcg_debug(lruvec, page);
+
+	return lruvec;
+}
+
 /**
  * mem_cgroup_update_lru_size - account for adding or removing an lru page
  * @lruvec: mem_cgroup per zone lru vector
@@ -2999,7 +3058,7 @@ void __memcg_kmem_uncharge_page(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 7098be122966..97a8667b4c2c 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));
@@ -176,7 +176,7 @@ unsigned int munlock_vma_page(struct page *page)
 	 * we clear it in the head page. It also stabilizes hpage_nr_pages().
 	 */
 	get_page(page);
-	spin_lock_irq(&pgdat->lru_lock);
+	lruvec = lock_page_lruvec_irq(page);
 	clearlru = TestClearPageLRU(page);
 
 	if (!TestClearPageMlocked(page)) {
@@ -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);
 	}
@@ -284,6 +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);
@@ -291,11 +289,17 @@ 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;
+		struct lruvec *new_lruvec;
 		bool clearlru;
 
 		clearlru = TestClearPageLRU(page);
-		spin_lock_irq(&zone->zone_pgdat->lru_lock);
+
+		new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+		if (new_lruvec != lruvec) {
+			if (lruvec)
+				unlock_page_lruvec_irq(lruvec);
+			lruvec = lock_page_lruvec_irq(page);
+		}
 
 		if (!TestClearPageMlocked(page)) {
 			delta_munlocked++;
@@ -314,9 +318,7 @@ 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));
 		del_page_from_lru_list(page, lruvec, page_lru(page));
-		spin_unlock_irq(&zone->zone_pgdat->lru_lock);
 		continue;
 
 		/*
@@ -326,14 +328,12 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
 		 * the last pin, __page_cache_release() would deadlock.
 		 */
 putback:
-		spin_unlock_irq(&zone->zone_pgdat->lru_lock);
 		pagevec_add(&pvec_putback, pvec->pages[i]);
 		pvec->pages[i] = NULL;
 	}
-	/* tempary disable irq, will remove later */
-	local_irq_disable();
 	__mod_zone_page_state(zone, NR_MLOCK, delta_munlocked);
-	local_irq_enable();
+	if (lruvec)
+		unlock_page_lruvec_irq(lruvec);
 
 	/* Now we can release pins of pages that we are not munlocking */
 	pagevec_release(&pvec_putback);
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 55eb2c2eed03..80de8a5182ca 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -79,15 +79,13 @@ static DEFINE_PER_CPU(struct lru_pvecs, lru_pvecs) = {
 static void __page_cache_release(struct page *page)
 {
 	if (PageLRU(page)) {
-		pg_data_t *pgdat = page_pgdat(page);
 		struct lruvec *lruvec;
 		unsigned long flags;
 
 		__ClearPageLRU(page);
-		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);
 }
@@ -206,19 +204,18 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 	void (*move_fn)(struct page *page, struct lruvec *lruvec), bool add)
 {
 	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);
+		struct lruvec *new_lruvec;
 
-		if (pagepgdat != pgdat) {
-			if (pgdat)
-				spin_unlock_irqrestore(&pgdat->lru_lock, flags);
-			pgdat = pagepgdat;
-			spin_lock_irqsave(&pgdat->lru_lock, flags);
+		new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+		if (lruvec != new_lruvec) {
+			if (lruvec)
+				unlock_page_lruvec_irqrestore(lruvec, flags);
+			lruvec = lock_page_lruvec_irqsave(page, &flags);
 		}
 
 		/* new page add to lru or page moving between lru */
@@ -231,8 +228,8 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 		if (!add)
 			SetPageLRU(page);
 	}
-	if (pgdat)
-		spin_unlock_irqrestore(&pgdat->lru_lock, flags);
+	if (lruvec)
+		unlock_page_lruvec_irqrestore(lruvec, flags);
 	release_pages(pvec->pages, pvec->nr);
 	pagevec_reinit(pvec);
 }
@@ -275,9 +272,8 @@ void lru_note_cost(struct lruvec *lruvec, bool file, unsigned int nr_pages)
 {
 	do {
 		unsigned long lrusize;
-		pglist_data *pgdat = lruvec_pgdat(lruvec);
 
-		spin_lock_irq(&pgdat->lru_lock);
+		spin_lock_irq(&lruvec->lru_lock);
 		/* Record cost event */
 		if (file)
 			lruvec->file_cost += nr_pages;
@@ -301,7 +297,7 @@ void lru_note_cost(struct lruvec *lruvec, bool file, unsigned int nr_pages)
 			lruvec->file_cost /= 2;
 			lruvec->anon_cost /= 2;
 		}
-		spin_unlock_irq(&pgdat->lru_lock);
+		spin_unlock_irq(&lruvec->lru_lock);
 	} while ((lruvec = parent_lruvec(lruvec)));
 }
 
@@ -366,11 +362,12 @@ 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));
-	spin_unlock_irq(&pgdat->lru_lock);
+	lruvec = lock_page_lruvec_irq(page);
+	__activate_page(page, lruvec, NULL);
+	unlock_page_lruvec_irq(lruvec);
 }
 #endif
 
@@ -820,8 +817,7 @@ 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);
 
@@ -831,21 +827,20 @@ 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
@@ -864,28 +859,28 @@ 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 (PageLRU(page)) {
-			struct pglist_data *pgdat = page_pgdat(page);
+			struct lruvec *new_lruvec;
 
-			if (pgdat != locked_pgdat) {
-				if (locked_pgdat)
-					spin_unlock_irqrestore(&locked_pgdat->lru_lock,
+			new_lruvec = mem_cgroup_page_lruvec(page,
+							page_pgdat(page));
+			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);
 			}
 
 			__ClearPageLRU(page);
-			lruvec = mem_cgroup_page_lruvec(page, locked_pgdat);
 			del_page_from_lru_list(page, lruvec, page_off_lru(page));
 		}
 
@@ -895,8 +890,8 @@ 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 f77748adc340..168c1659e430 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1774,15 +1774,13 @@ int isolate_lru_page(struct page *page)
 	WARN_RATELIMIT(PageTail(page), "trying to isolate tail page");
 
 	if (TestClearPageLRU(page)) {
-		pg_data_t *pgdat = page_pgdat(page);
 		struct lruvec *lruvec;
 		int lru = page_lru(page);
 
 		get_page(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;
 	}
 
@@ -1849,20 +1847,22 @@ 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;
+	struct lruvec *orig_lruvec = lruvec;
 	enum lru_list lru;
 
 	while (!list_empty(list)) {
+		struct lruvec *new_lruvec = NULL;
+
 		page = lru_to_page(list);
 		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;
 		}
 
@@ -1876,6 +1876,12 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 		 *                                        list_add(&page->lru,)
 		 *     list_add(&page->lru,) //corrupt
 		 */
+		new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+		if (new_lruvec != lruvec) {
+			if (lruvec)
+				spin_unlock_irq(&lruvec->lru_lock);
+			lruvec = lock_page_lruvec_irq(page);
+		}
 		SetPageLRU(page);
 
 		if (unlikely(put_page_testzero(page))) {
@@ -1883,16 +1889,15 @@ 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);
 				destroy_compound_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);
 
@@ -1902,6 +1907,11 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 		if (PageActive(page))
 			workingset_age_nonresident(lruvec, nr_pages);
 	}
+	if (orig_lruvec != lruvec) {
+		if (lruvec)
+			spin_unlock_irq(&lruvec->lru_lock);
+		spin_lock_irq(&orig_lruvec->lru_lock);
+	}
 
 	/*
 	 * To save our caller's stack, now use input list for pages to free.
@@ -1957,7 +1967,7 @@ 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);
@@ -1969,7 +1979,7 @@ static int current_may_throttle(void)
 	__count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned);
 	__count_vm_events(PGSCAN_ANON + file, nr_scanned);
 
-	spin_unlock_irq(&pgdat->lru_lock);
+	spin_unlock_irq(&lruvec->lru_lock);
 
 	if (nr_taken == 0)
 		return 0;
@@ -1977,7 +1987,7 @@ 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);
 	move_pages_to_lru(lruvec, &page_list);
 
 	__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
@@ -1986,7 +1996,7 @@ static int current_may_throttle(void)
 		__count_vm_events(item, nr_reclaimed);
 	__count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed);
 	__count_vm_events(PGSTEAL_ANON + file, nr_reclaimed);
-	spin_unlock_irq(&pgdat->lru_lock);
+	spin_unlock_irq(&lruvec->lru_lock);
 
 	lru_note_cost(lruvec, file, stat.nr_pageout);
 	mem_cgroup_uncharge_list(&page_list);
@@ -2039,7 +2049,7 @@ 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);
@@ -2049,7 +2059,7 @@ 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();
@@ -2095,7 +2105,7 @@ 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);
 
 	nr_activate = move_pages_to_lru(lruvec, &l_active);
 	nr_deactivate = move_pages_to_lru(lruvec, &l_inactive);
@@ -2106,7 +2116,7 @@ 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);
@@ -2696,10 +2706,10 @@ static void shrink_node(pg_data_t *pgdat, struct scan_control *sc)
 	/*
 	 * Determine the scan balance between anon and file LRUs.
 	 */
-	spin_lock_irq(&pgdat->lru_lock);
+	spin_lock_irq(&target_lruvec->lru_lock);
 	sc->anon_cost = target_lruvec->anon_cost;
 	sc->file_cost = target_lruvec->file_cost;
-	spin_unlock_irq(&pgdat->lru_lock);
+	spin_unlock_irq(&target_lruvec->lru_lock);
 
 	/*
 	 * Target desirable inactive:active list ratios for the anon
@@ -4275,24 +4285,22 @@ int node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned int order)
  */
 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;
 
 		pgscanned++;
-		if (pagepgdat != pgdat) {
-			if (pgdat)
-				spin_unlock_irq(&pgdat->lru_lock);
-			pgdat = pagepgdat;
-			spin_lock_irq(&pgdat->lru_lock);
+		new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+		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 (!PageLRU(page) || !PageUnevictable(page))
 			continue;
@@ -4308,10 +4316,10 @@ 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


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 17/20] mm/lru: introduce the relock_page_lruvec function
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (15 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 16/20] mm/lru: replace pgdat lru_lock with lruvec lock Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 18/20] mm/vmscan: use relock for move_pages_to_lru Alex Shi
                   ` (2 subsequent siblings)
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

Use this new function to replace repeated same code.

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
---
 mm/mlock.c  |  9 +--------
 mm/swap.c   | 25 ++++++-------------------
 mm/vmscan.c |  8 +-------
 3 files changed, 8 insertions(+), 34 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c
index 97a8667b4c2c..fa976a5b91c7 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -289,17 +289,10 @@ 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 *new_lruvec;
 		bool clearlru;
 
 		clearlru = TestClearPageLRU(page);
-
-		new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
-		if (new_lruvec != lruvec) {
-			if (lruvec)
-				unlock_page_lruvec_irq(lruvec);
-			lruvec = lock_page_lruvec_irq(page);
-		}
+		lruvec = relock_page_lruvec_irq(page, lruvec);
 
 		if (!TestClearPageMlocked(page)) {
 			delta_munlocked++;
diff --git a/mm/swap.c b/mm/swap.c
index 80de8a5182ca..c4d8710c8957 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -209,20 +209,12 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
 
 	for (i = 0; i < pagevec_count(pvec); i++) {
 		struct page *page = pvec->pages[i];
-		struct lruvec *new_lruvec;
-
-		new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
-		if (lruvec != new_lruvec) {
-			if (lruvec)
-				unlock_page_lruvec_irqrestore(lruvec, flags);
-			lruvec = lock_page_lruvec_irqsave(page, &flags);
-		}
 
 		/* new page add to lru or page moving between lru */
 		if (!add && !TestClearPageLRU(page))
 			continue;
 
-		lruvec = mem_cgroup_page_lruvec(page, pgdat);
+		lruvec = relock_page_lruvec_irqsave(page, lruvec, &flags);
 		(*move_fn)(page, lruvec);
 
 		if (!add)
@@ -868,17 +860,12 @@ void release_pages(struct page **pages, int nr)
 		}
 
 		if (PageLRU(page)) {
-			struct lruvec *new_lruvec;
-
-			new_lruvec = mem_cgroup_page_lruvec(page,
-							page_pgdat(page));
-			if (new_lruvec != lruvec) {
-				if (lruvec)
-					unlock_page_lruvec_irqrestore(lruvec,
-									flags);
+			struct lruvec *pre_lruvec = lruvec;
+
+			lruvec = relock_page_lruvec_irqsave(page, lruvec,
+									&flags);
+			if (pre_lruvec != lruvec)
 				lock_batch = 0;
-				lruvec = lock_page_lruvec_irqsave(page, &flags);
-			}
 
 			__ClearPageLRU(page);
 			del_page_from_lru_list(page, lruvec, page_off_lru(page));
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 168c1659e430..bdb53a678e7e 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4292,15 +4292,9 @@ 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;
 
 		pgscanned++;
-		new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
-		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 (!PageLRU(page) || !PageUnevictable(page))
 			continue;
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 18/20] mm/vmscan: use relock for move_pages_to_lru
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (16 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 17/20] mm/lru: introduce the relock_page_lruvec function Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 19/20] mm/pgdat: remove pgdat lru_lock Alex Shi
  2020-07-03  5:07 ` [PATCH v14 20/20] mm/lru: revise the comments of lru_lock Alex Shi
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

From: Hugh Dickins <hughd@google.com>

Use the relock function to replace relocking action. And try to save few
lock times.

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
---
 mm/vmscan.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index bdb53a678e7e..078a1640ec60 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1854,15 +1854,15 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 	enum lru_list lru;
 
 	while (!list_empty(list)) {
-		struct lruvec *new_lruvec = NULL;
-
 		page = lru_to_page(list);
 		VM_BUG_ON_PAGE(PageLRU(page), page);
 		list_del(&page->lru);
 		if (unlikely(!page_evictable(page))) {
-			spin_unlock_irq(&lruvec->lru_lock);
+			if (lruvec) {
+				spin_unlock_irq(&lruvec->lru_lock);
+				lruvec = NULL;
+			}
 			putback_lru_page(page);
-			spin_lock_irq(&lruvec->lru_lock);
 			continue;
 		}
 
@@ -1876,12 +1876,7 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 		 *                                        list_add(&page->lru,)
 		 *     list_add(&page->lru,) //corrupt
 		 */
-		new_lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
-		if (new_lruvec != lruvec) {
-			if (lruvec)
-				spin_unlock_irq(&lruvec->lru_lock);
-			lruvec = lock_page_lruvec_irq(page);
-		}
+		lruvec = relock_page_lruvec_irq(page, lruvec);
 		SetPageLRU(page);
 
 		if (unlikely(put_page_testzero(page))) {
@@ -1890,8 +1885,8 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 
 			if (unlikely(PageCompound(page))) {
 				spin_unlock_irq(&lruvec->lru_lock);
+				lruvec = NULL;
 				destroy_compound_page(page);
-				spin_lock_irq(&lruvec->lru_lock);
 			} else
 				list_add(&page->lru, &pages_to_free);
 
-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 19/20] mm/pgdat: remove pgdat lru_lock
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (17 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 18/20] mm/vmscan: use relock for move_pages_to_lru Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  2020-07-03  5:07 ` [PATCH v14 20/20] mm/lru: revise the comments of lru_lock Alex Shi
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

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 36c1680efd90..8d7318ce5f62 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -735,7 +735,6 @@ 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 48eb0f1410d4..05ce6e1a3098 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6721,7 +6721,6 @@ 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


^ permalink raw reply	[flat|nested] 35+ messages in thread

* [PATCH v14 20/20] mm/lru: revise the comments of lru_lock
  2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
                   ` (18 preceding siblings ...)
  2020-07-03  5:07 ` [PATCH v14 19/20] mm/pgdat: remove pgdat lru_lock Alex Shi
@ 2020-07-03  5:07 ` Alex Shi
  19 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-03  5:07 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

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     | 21 +++++++++------------
 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                                          |  4 ++--
 mm/vmscan.c                                        | 12 ++++++++----
 10 files changed, 36 insertions(+), 50 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 12757e63b26c..24450696579f 100644
--- a/Documentation/admin-guide/cgroup-v1/memory.rst
+++ b/Documentation/admin-guide/cgroup-v1/memory.rst
@@ -285,20 +285,17 @@ When oom event notifier is registered, event will be delivered.
 2.6 Locking
 -----------
 
-   lock_page_cgroup()/unlock_page_cgroup() should not be called under
-   the i_pages lock.
+Lock order is as follows:
 
-   Other lock order is following:
+  Page lock (PG_locked bit of page->flags)
+    mm->page_table_lock or split pte_lock
+      lock_page_memcg (memcg->move_lock)
+        mapping->i_pages lock
+          lruvec->lru_lock.
 
-   PG_locked.
-     mm->page_table_lock
-         pgdat->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-memcgroup LRU (cgroup's private LRU) is guarded by
+lruvec->lru_lock; PG_lru bit of page->flags is cleared before
+isolating a page from its LRU under lruvec->lru_lock.
 
 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 64ede5f150dc..44738cdb5a55 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 8d7318ce5f62..dddeabd6ea8d 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -115,7 +115,7 @@ 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 f0ae9a6308cb..1b42aaae4d3e 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 d5e56be42f21..926d7d95dc1d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3057,7 +3057,7 @@ void __memcg_kmem_uncharge_page(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 5fe2dedce1fc..7fbc382e6f9e 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -28,12 +28,12 @@
  *           hugetlb_fault_mutex (hugetlbfs specific page fault mutex)
  *           anon_vma->rwsem
  *             mm->page_table_lock or pte_lock
- *               pgdat->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)
- *                   mem_cgroup_{begin,end}_page_stat (memcg->move_lock)
+ *                   lock_page_memcg move_lock (in __set_page_dirty_buffers)
  *                     i_pages lock (widely used)
+ *                       lock_page_lruvec_irq lruvec->lru_lock
  *                 inode->i_lock (in set_page_dirty's __mark_inode_dirty)
  *                 bdi.wb->list_lock (in set_page_dirty's __mark_inode_dirty)
  *                   sb_lock (within inode_lock in fs/fs-writeback.c)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 078a1640ec60..bb3ac52de058 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1620,14 +1620,16 @@ 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.
@@ -1826,14 +1828,16 @@ 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


^ permalink raw reply	[flat|nested] 35+ messages in thread

* Re: [PATCH v14 15/20] mm/swap: serialize memcg changes during pagevec_lru_move_fn
  2020-07-03  5:07 ` [PATCH v14 15/20] mm/swap: serialize memcg changes during pagevec_lru_move_fn Alex Shi
@ 2020-07-03  9:13   ` Konstantin Khlebnikov
  2020-07-04 11:34     ` Alex Shi
  0 siblings, 1 reply; 35+ messages in thread
From: Konstantin Khlebnikov @ 2020-07-03  9:13 UTC (permalink / raw)
  To: Alex Shi
  Cc: Andrew Morton, Mel Gorman, Tejun Heo, Hugh Dickins,
	Константин
	Хлебников,
	daniel.m.jordan, yang.shi, Matthew Wilcox, Johannes Weiner, lkp,
	linux-mm, Linux Kernel Mailing List, Cgroups, shakeelb,
	Joonsoo Kim, richard.weiyang

On Fri, Jul 3, 2020 at 8:09 AM Alex Shi <alex.shi@linux.alibaba.com> wrote:
>
> Hugh Dickins' found a memcg change bug on original version:
> If we want to change the pgdat->lru_lock to memcg's lruvec lock, we have
> to serialize mem_cgroup_move_account during pagevec_lru_move_fn. The
> possible bad scenario would like:
>
>         cpu 0                                   cpu 1
> lruvec = mem_cgroup_page_lruvec()
>                                         if (!isolate_lru_page())
>                                                 mem_cgroup_move_account
>
> spin_lock_irqsave(&lruvec->lru_lock <== wrong lock.
>
> So we need the ClearPageLRU to block isolate_lru_page(), then serialize
> the memcg change here.
>
> Reported-by: Hugh Dickins <hughd@google.com>
> Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> ---
>  mm/swap.c | 31 +++++++++++++++++++------------
>  1 file changed, 19 insertions(+), 12 deletions(-)
>
> diff --git a/mm/swap.c b/mm/swap.c
> index b24d5f69b93a..55eb2c2eed03 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -203,7 +203,7 @@ int get_kernel_page(unsigned long start, int write, struct page **pages)
>  EXPORT_SYMBOL_GPL(get_kernel_page);
>
>  static void pagevec_lru_move_fn(struct pagevec *pvec,
> -       void (*move_fn)(struct page *page, struct lruvec *lruvec))
> +       void (*move_fn)(struct page *page, struct lruvec *lruvec), bool add)
>  {
>         int i;
>         struct pglist_data *pgdat = NULL;
> @@ -221,8 +221,15 @@ static void pagevec_lru_move_fn(struct pagevec *pvec,
>                         spin_lock_irqsave(&pgdat->lru_lock, flags);
>                 }
>
> +               /* new page add to lru or page moving between lru */
> +               if (!add && !TestClearPageLRU(page))
> +                       continue;
> +
>                 lruvec = mem_cgroup_page_lruvec(page, pgdat);
>                 (*move_fn)(page, lruvec);
> +
> +               if (!add)
> +                       SetPageLRU(page);
>         }
>         if (pgdat)
>                 spin_unlock_irqrestore(&pgdat->lru_lock, flags);
> @@ -259,7 +266,7 @@ void rotate_reclaimable_page(struct page *page)
>                 local_lock_irqsave(&lru_rotate.lock, flags);
>                 pvec = this_cpu_ptr(&lru_rotate.pvec);
>                 if (!pagevec_add(pvec, page) || PageCompound(page))
> -                       pagevec_lru_move_fn(pvec, pagevec_move_tail_fn);
> +                       pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, false);
>                 local_unlock_irqrestore(&lru_rotate.lock, flags);
>         }
>  }
> @@ -328,7 +335,7 @@ static void activate_page_drain(int cpu)
>         struct pagevec *pvec = &per_cpu(lru_pvecs.activate_page, cpu);
>
>         if (pagevec_count(pvec))
> -               pagevec_lru_move_fn(pvec, __activate_page);
> +               pagevec_lru_move_fn(pvec, __activate_page, false);
>  }
>
>  static bool need_activate_page_drain(int cpu)
> @@ -346,7 +353,7 @@ void activate_page(struct page *page)
>                 pvec = this_cpu_ptr(&lru_pvecs.activate_page);
>                 get_page(page);
>                 if (!pagevec_add(pvec, page) || PageCompound(page))
> -                       pagevec_lru_move_fn(pvec, __activate_page);
> +                       pagevec_lru_move_fn(pvec, __activate_page, false);
>                 local_unlock(&lru_pvecs.lock);
>         }
>  }
> @@ -621,21 +628,21 @@ void lru_add_drain_cpu(int cpu)
>
>                 /* No harm done if a racing interrupt already did this */
>                 local_lock_irqsave(&lru_rotate.lock, flags);
> -               pagevec_lru_move_fn(pvec, pagevec_move_tail_fn);
> +               pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, false);
>                 local_unlock_irqrestore(&lru_rotate.lock, flags);
>         }
>
>         pvec = &per_cpu(lru_pvecs.lru_deactivate_file, cpu);
>         if (pagevec_count(pvec))
> -               pagevec_lru_move_fn(pvec, lru_deactivate_file_fn);
> +               pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, false);
>
>         pvec = &per_cpu(lru_pvecs.lru_deactivate, cpu);
>         if (pagevec_count(pvec))
> -               pagevec_lru_move_fn(pvec, lru_deactivate_fn);
> +               pagevec_lru_move_fn(pvec, lru_deactivate_fn, false);
>
>         pvec = &per_cpu(lru_pvecs.lru_lazyfree, cpu);
>         if (pagevec_count(pvec))
> -               pagevec_lru_move_fn(pvec, lru_lazyfree_fn);
> +               pagevec_lru_move_fn(pvec, lru_lazyfree_fn, false);
>
>         activate_page_drain(cpu);
>  }
> @@ -664,7 +671,7 @@ void deactivate_file_page(struct page *page)
>                 pvec = this_cpu_ptr(&lru_pvecs.lru_deactivate_file);
>
>                 if (!pagevec_add(pvec, page) || PageCompound(page))
> -                       pagevec_lru_move_fn(pvec, lru_deactivate_file_fn);
> +                       pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, false);
>                 local_unlock(&lru_pvecs.lock);
>         }
>  }
> @@ -686,7 +693,7 @@ void deactivate_page(struct page *page)
>                 pvec = this_cpu_ptr(&lru_pvecs.lru_deactivate);
>                 get_page(page);
>                 if (!pagevec_add(pvec, page) || PageCompound(page))
> -                       pagevec_lru_move_fn(pvec, lru_deactivate_fn);
> +                       pagevec_lru_move_fn(pvec, lru_deactivate_fn, false);
>                 local_unlock(&lru_pvecs.lock);
>         }
>  }
> @@ -708,7 +715,7 @@ void mark_page_lazyfree(struct page *page)
>                 pvec = this_cpu_ptr(&lru_pvecs.lru_lazyfree);
>                 get_page(page);
>                 if (!pagevec_add(pvec, page) || PageCompound(page))
> -                       pagevec_lru_move_fn(pvec, lru_lazyfree_fn);
> +                       pagevec_lru_move_fn(pvec, lru_lazyfree_fn, false);
>                 local_unlock(&lru_pvecs.lock);
>         }
>  }
> @@ -976,7 +983,7 @@ 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);
> +       pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn, true);
>  }

It seems better to open code version in lru_add than adding a bool
argument which is true just for one user.

Also with this new lru protection logic lru_add could be optimized:
It could prepare a list of pages and under lru_lock do only list
splice and bumping counter.
Since PageLRU isn't set yet nobody could touch these pages in lru.
After that lru_add could iterate pages from first to last without
lru_lock to set PageLRU and drop reference.

So, lru_add will do O(1) operations under lru_lock regardless of the
count of pages it added.

Actually per-cpu vector for adding could be replaced with per-cpu
lists and\or per-lruvec atomic slist.
Thus incommig pages will be already in list structure rather than page vector.
This allows to accumulate more pages and offload adding to kswapd or
direct reclaim.

>
>  /**
> --
> 1.8.3.1
>
>

^ permalink raw reply	[flat|nested] 35+ messages in thread

* Re: [PATCH v14 15/20] mm/swap: serialize memcg changes during pagevec_lru_move_fn
  2020-07-03  9:13   ` Konstantin Khlebnikov
@ 2020-07-04 11:34     ` Alex Shi
  2020-07-04 11:39       ` Matthew Wilcox
  0 siblings, 1 reply; 35+ messages in thread
From: Alex Shi @ 2020-07-04 11:34 UTC (permalink / raw)
  To: Konstantin Khlebnikov
  Cc: Andrew Morton, Mel Gorman, Tejun Heo, Hugh Dickins,
	Константин
	Хлебников,
	daniel.m.jordan, yang.shi, Matthew Wilcox, Johannes Weiner, lkp,
	linux-mm, Linux Kernel Mailing List, Cgroups, shakeelb,
	Joonsoo Kim, richard.weiyang



在 2020/7/3 下午5:13, Konstantin Khlebnikov 写道:
>> @@ -976,7 +983,7 @@ 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);
>> +       pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn, true);
>>  }
> It seems better to open code version in lru_add than adding a bool
> argument which is true just for one user.

Right, I will rewrite this part as your suggestion. Thanks!

> 
> Also with this new lru protection logic lru_add could be optimized:
> It could prepare a list of pages and under lru_lock do only list
> splice and bumping counter.
> Since PageLRU isn't set yet nobody could touch these pages in lru.
> After that lru_add could iterate pages from first to last without
> lru_lock to set PageLRU and drop reference.
> 
> So, lru_add will do O(1) operations under lru_lock regardless of the
> count of pages it added.
> 
> Actually per-cpu vector for adding could be replaced with per-cpu
> lists and\or per-lruvec atomic slist.
> Thus incommig pages will be already in list structure rather than page vector.
> This allows to accumulate more pages and offload adding to kswapd or
> direct reclaim.
> 

That's a great idea! Guess what the new struct we need would be like this?
I like to try this. :)


diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h
index 081d934eda64..d62778c8c184 100644
--- a/include/linux/pagevec.h
+++ b/include/linux/pagevec.h
@@ -20,7 +20,7 @@
 struct pagevec {
        unsigned char nr;
        bool percpu_pvec_drained;
-       struct page *pages[PAGEVEC_SIZE];
+       struct list_head veclist;
 };

^ permalink raw reply	[flat|nested] 35+ messages in thread

* Re: [PATCH v14 15/20] mm/swap: serialize memcg changes during pagevec_lru_move_fn
  2020-07-04 11:34     ` Alex Shi
@ 2020-07-04 11:39       ` Matthew Wilcox
  2020-07-04 13:12         ` Alex Shi
  0 siblings, 1 reply; 35+ messages in thread
From: Matthew Wilcox @ 2020-07-04 11:39 UTC (permalink / raw)
  To: Alex Shi
  Cc: Konstantin Khlebnikov, Andrew Morton, Mel Gorman, Tejun Heo,
	Hugh Dickins,
	Константин
	Хлебников,
	daniel.m.jordan, yang.shi, Johannes Weiner, lkp, linux-mm,
	Linux Kernel Mailing List, Cgroups, shakeelb, Joonsoo Kim,
	richard.weiyang

On Sat, Jul 04, 2020 at 07:34:59PM +0800, Alex Shi wrote:
> That's a great idea! Guess what the new struct we need would be like this?
> I like to try this. :)
> 
> 
> diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h
> index 081d934eda64..d62778c8c184 100644
> --- a/include/linux/pagevec.h
> +++ b/include/linux/pagevec.h
> @@ -20,7 +20,7 @@
>  struct pagevec {
>         unsigned char nr;
>         bool percpu_pvec_drained;
> -       struct page *pages[PAGEVEC_SIZE];
> +       struct list_head veclist;
>  };

pagevecs are used not just for LRU.  If you want to use a list_head for
LRU then define a new structure.


^ permalink raw reply	[flat|nested] 35+ messages in thread

* Re: [PATCH v14 15/20] mm/swap: serialize memcg changes during pagevec_lru_move_fn
  2020-07-04 11:39       ` Matthew Wilcox
@ 2020-07-04 13:12         ` Alex Shi
  2020-07-04 13:33           ` Matthew Wilcox
  0 siblings, 1 reply; 35+ messages in thread
From: Alex Shi @ 2020-07-04 13:12 UTC (permalink / raw)
  To: Matthew Wilcox
  Cc: Konstantin Khlebnikov, Andrew Morton, Mel Gorman, Tejun Heo,
	Hugh Dickins,
	Константин
	Хлебников,
	daniel.m.jordan, yang.shi, Johannes Weiner, lkp, linux-mm,
	Linux Kernel Mailing List, Cgroups, shakeelb, Joonsoo Kim,
	richard.weiyang



在 2020/7/4 下午7:39, Matthew Wilcox 写道:
> On Sat, Jul 04, 2020 at 07:34:59PM +0800, Alex Shi wrote:
>> That's a great idea! Guess what the new struct we need would be like this?
>> I like to try this. :)
>>
>>
>> diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h
>> index 081d934eda64..d62778c8c184 100644
>> --- a/include/linux/pagevec.h
>> +++ b/include/linux/pagevec.h
>> @@ -20,7 +20,7 @@
>>  struct pagevec {
>>         unsigned char nr;
>>         bool percpu_pvec_drained;
>> -       struct page *pages[PAGEVEC_SIZE];
>> +       struct list_head veclist;
>>  };
> 
> pagevecs are used not just for LRU.  If you want to use a list_head for
> LRU then define a new structure.
> 

yes, there are much page don't use page->lru, like slab etc. we need a new struct.

Thanks!
Alex

^ permalink raw reply	[flat|nested] 35+ messages in thread

* Re: [PATCH v14 15/20] mm/swap: serialize memcg changes during pagevec_lru_move_fn
  2020-07-04 13:12         ` Alex Shi
@ 2020-07-04 13:33           ` Matthew Wilcox
  2020-07-04 15:47             ` Alex Shi
  0 siblings, 1 reply; 35+ messages in thread
From: Matthew Wilcox @ 2020-07-04 13:33 UTC (permalink / raw)
  To: Alex Shi
  Cc: Konstantin Khlebnikov, Andrew Morton, Mel Gorman, Tejun Heo,
	Hugh Dickins,
	Константин
	Хлебников,
	daniel.m.jordan, yang.shi, Johannes Weiner, lkp, linux-mm,
	Linux Kernel Mailing List, Cgroups, shakeelb, Joonsoo Kim,
	richard.weiyang

On Sat, Jul 04, 2020 at 09:12:46PM +0800, Alex Shi wrote:
> 在 2020/7/4 下午7:39, Matthew Wilcox 写道:
> > On Sat, Jul 04, 2020 at 07:34:59PM +0800, Alex Shi wrote:
> >> That's a great idea! Guess what the new struct we need would be like this?
> >> I like to try this. :)
> >>
> >>
> >> diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h
> >> index 081d934eda64..d62778c8c184 100644
> >> --- a/include/linux/pagevec.h
> >> +++ b/include/linux/pagevec.h
> >> @@ -20,7 +20,7 @@
> >>  struct pagevec {
> >>         unsigned char nr;
> >>         bool percpu_pvec_drained;
> >> -       struct page *pages[PAGEVEC_SIZE];
> >> +       struct list_head veclist;
> >>  };
> > 
> > pagevecs are used not just for LRU.  If you want to use a list_head for
> > LRU then define a new structure.
> 
> yes, there are much page don't use page->lru, like slab etc. we need a new struct.

That's not what I mean.  Slab pages aren't on the LRU anyway.

Consider the callers of page_cache_delete_batch().  These use a pagevec
for a non-LRU purpose, and they will be much slower with a list_head than
with an array.

^ permalink raw reply	[flat|nested] 35+ messages in thread

* Re: [PATCH v14 15/20] mm/swap: serialize memcg changes during pagevec_lru_move_fn
  2020-07-04 13:33           ` Matthew Wilcox
@ 2020-07-04 15:47             ` Alex Shi
  0 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-04 15:47 UTC (permalink / raw)
  To: Matthew Wilcox
  Cc: Konstantin Khlebnikov, Andrew Morton, Mel Gorman, Tejun Heo,
	Hugh Dickins,
	Константин
	Хлебников,
	daniel.m.jordan, yang.shi, Johannes Weiner, lkp, linux-mm,
	Linux Kernel Mailing List, Cgroups, shakeelb, Joonsoo Kim,
	richard.weiyang



在 2020/7/4 下午9:33, Matthew Wilcox 写道:
> On Sat, Jul 04, 2020 at 09:12:46PM +0800, Alex Shi wrote:
>> 在 2020/7/4 下午7:39, Matthew Wilcox 写道:
>>> On Sat, Jul 04, 2020 at 07:34:59PM +0800, Alex Shi wrote:
>>>> That's a great idea! Guess what the new struct we need would be like this?
>>>> I like to try this. :)
>>>>
>>>>
>>>> diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h
>>>> index 081d934eda64..d62778c8c184 100644
>>>> --- a/include/linux/pagevec.h
>>>> +++ b/include/linux/pagevec.h
>>>> @@ -20,7 +20,7 @@
>>>>  struct pagevec {
>>>>         unsigned char nr;
>>>>         bool percpu_pvec_drained;
>>>> -       struct page *pages[PAGEVEC_SIZE];
>>>> +       struct list_head veclist;
>>>>  };
>>>
>>> pagevecs are used not just for LRU.  If you want to use a list_head for
>>> LRU then define a new structure.
>>
>> yes, there are much page don't use page->lru, like slab etc. we need a new struct> 
> That's not what I mean.  Slab pages aren't on the LRU anyway.

Right. I mean, that's reason for a new struct if we change to list.

> 
> Consider the callers of page_cache_delete_batch().  These use a pagevec
> for a non-LRU purpose, and they will be much slower with a list_head than
> with an array.
> 

Thanks for the info.
If the list is slower than pagevec, maybe it's not worth to do the change.
Since pagevec could handle any kind of pages, anon/file, non-active/active, but one
list only fit for just one kind of list. 5 kinds of list adding would increase the
complexity. Consider this, I am wondering if it's worth?

Thanks
Alex

^ permalink raw reply	[flat|nested] 35+ messages in thread

* Re: [PATCH v14 07/20] mm/thp: narrow lru locking
  2020-07-03  5:07 ` [PATCH v14 07/20] mm/thp: narrow lru locking Alex Shi
@ 2020-07-06  9:15   ` Alex Shi
  2020-07-06 11:35     ` Matthew Wilcox
  0 siblings, 1 reply; 35+ messages in thread
From: Alex Shi @ 2020-07-06  9:15 UTC (permalink / raw)
  To: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	willy, hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

Hi Kirill & Johannes & Matthew,

Would you like to give some comments or share your concern of this patchset,
specialy for THP part? 

Many Thanks
Alex

在 2020/7/3 下午1:07, Alex Shi 写道:
> lru_lock and page cache xa_lock have no reason with current sequence,
> put them together isn't necessary. let's narrow the lru locking, but
> left the local_irq_disable to block interrupt re-entry and statistic update.
> 
> Hugh Dickins point: split_huge_page_to_list() was already silly,to be
> using the _irqsave variant: it's just been taking sleeping locks, so
> would already be broken if entered with interrupts enabled.
> so we can save passing flags argument down to __split_huge_page().
> 
> Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
> Cc: Hugh Dickins <hughd@google.com>
> Cc: Kirill A. Shutemov <kirill@shutemov.name>
> Cc: Andrea Arcangeli <aarcange@redhat.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> ---
>  mm/huge_memory.c | 24 ++++++++++++------------
>  1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index b18f21da4dac..607869330329 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -2433,7 +2433,7 @@ 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);
> @@ -2442,8 +2442,6 @@ static void __split_huge_page(struct page *page, struct list_head *list,
>  	unsigned long offset = 0;
>  	int i;
>  
> -	lruvec = mem_cgroup_page_lruvec(head, pgdat);
> -
>  	/* complete memcg works before add pages to LRU */
>  	mem_cgroup_split_huge_fixup(head);
>  
> @@ -2455,6 +2453,11 @@ static void __split_huge_page(struct page *page, struct list_head *list,
>  		xa_lock(&swap_cache->i_pages);
>  	}
>  
> +	/* lock lru list/PageCompound, ref freezed by page_ref_freeze */
> +	spin_lock(&pgdat->lru_lock);
> +
> +	lruvec = mem_cgroup_page_lruvec(head, pgdat);
> +
>  	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 */
> @@ -2474,6 +2477,8 @@ static void __split_huge_page(struct page *page, struct list_head *list,
>  	}
>  
>  	ClearPageCompound(head);
> +	spin_unlock(&pgdat->lru_lock);
> +	/* Caller disabled irqs, so they are still disabled here */
>  
>  	split_page_owner(head, HPAGE_PMD_ORDER);
>  
> @@ -2491,8 +2496,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
>  		page_ref_add(head, 2);
>  		xa_unlock(&head->mapping->i_pages);
>  	}
> -
> -	spin_unlock_irqrestore(&pgdat->lru_lock, flags);
> +	local_irq_enable();
>  
>  	remap_page(head);
>  
> @@ -2631,12 +2635,10 @@ 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;
> -	unsigned long flags;
>  	pgoff_t end;
>  
>  	VM_BUG_ON_PAGE(is_huge_zero_page(head), head);
> @@ -2697,9 +2699,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
>  	unmap_page(head);
>  	VM_BUG_ON_PAGE(compound_mapcount(head), head);
>  
> -	/* prevent PageLRU to go away from under us, and freeze lru stats */
> -	spin_lock_irqsave(&pgdata->lru_lock, flags);
> -
> +	local_irq_disable();
>  	if (mapping) {
>  		XA_STATE(xas, &mapping->i_pages, page_index(head));
>  
> @@ -2729,7 +2729,7 @@ 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) };
>  
> @@ -2748,7 +2748,7 @@ 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);
> +		local_irq_enable();
>  		remap_page(head);
>  		ret = -EBUSY;
>  	}
> 

^ permalink raw reply	[flat|nested] 35+ messages in thread

* Re: [PATCH v14 07/20] mm/thp: narrow lru locking
  2020-07-06  9:15   ` Alex Shi
@ 2020-07-06 11:35     ` Matthew Wilcox
  2020-07-07  4:52       ` Hugh Dickins
  2020-07-07 10:51       ` Alex Shi
  0 siblings, 2 replies; 35+ messages in thread
From: Matthew Wilcox @ 2020-07-06 11:35 UTC (permalink / raw)
  To: Alex Shi
  Cc: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang

On Mon, Jul 06, 2020 at 05:15:09PM +0800, Alex Shi wrote:
> Hi Kirill & Johannes & Matthew,
> 
> Would you like to give some comments or share your concern of this patchset,
> specialy for THP part? 

I don't have the brain space to understand this patch set fully at
the moment.  I'll note that the realtime folks are doing their best to
stamp out users of local_irq_disable(), so they won't be pleased to see
you adding a new one.  Also, you removed the comment explaining why the
lock needed to be taken.

> Many Thanks
> Alex
> 
> 在 2020/7/3 下午1:07, Alex Shi 写道:
> > lru_lock and page cache xa_lock have no reason with current sequence,
> > put them together isn't necessary. let's narrow the lru locking, but
> > left the local_irq_disable to block interrupt re-entry and statistic update.
> > 
> > Hugh Dickins point: split_huge_page_to_list() was already silly,to be
> > using the _irqsave variant: it's just been taking sleeping locks, so
> > would already be broken if entered with interrupts enabled.
> > so we can save passing flags argument down to __split_huge_page().
> > 
> > Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
> > Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
> > Cc: Hugh Dickins <hughd@google.com>
> > Cc: Kirill A. Shutemov <kirill@shutemov.name>
> > Cc: Andrea Arcangeli <aarcange@redhat.com>
> > Cc: Johannes Weiner <hannes@cmpxchg.org>
> > Cc: Matthew Wilcox <willy@infradead.org>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: linux-mm@kvack.org
> > Cc: linux-kernel@vger.kernel.org
> > ---
> >  mm/huge_memory.c | 24 ++++++++++++------------
> >  1 file changed, 12 insertions(+), 12 deletions(-)
> > 
> > diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> > index b18f21da4dac..607869330329 100644
> > --- a/mm/huge_memory.c
> > +++ b/mm/huge_memory.c
> > @@ -2433,7 +2433,7 @@ 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);
> > @@ -2442,8 +2442,6 @@ static void __split_huge_page(struct page *page, struct list_head *list,
> >  	unsigned long offset = 0;
> >  	int i;
> >  
> > -	lruvec = mem_cgroup_page_lruvec(head, pgdat);
> > -
> >  	/* complete memcg works before add pages to LRU */
> >  	mem_cgroup_split_huge_fixup(head);
> >  
> > @@ -2455,6 +2453,11 @@ static void __split_huge_page(struct page *page, struct list_head *list,
> >  		xa_lock(&swap_cache->i_pages);
> >  	}
> >  
> > +	/* lock lru list/PageCompound, ref freezed by page_ref_freeze */
> > +	spin_lock(&pgdat->lru_lock);
> > +
> > +	lruvec = mem_cgroup_page_lruvec(head, pgdat);
> > +
> >  	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 */
> > @@ -2474,6 +2477,8 @@ static void __split_huge_page(struct page *page, struct list_head *list,
> >  	}
> >  
> >  	ClearPageCompound(head);
> > +	spin_unlock(&pgdat->lru_lock);
> > +	/* Caller disabled irqs, so they are still disabled here */
> >  
> >  	split_page_owner(head, HPAGE_PMD_ORDER);
> >  
> > @@ -2491,8 +2496,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
> >  		page_ref_add(head, 2);
> >  		xa_unlock(&head->mapping->i_pages);
> >  	}
> > -
> > -	spin_unlock_irqrestore(&pgdat->lru_lock, flags);
> > +	local_irq_enable();
> >  
> >  	remap_page(head);
> >  
> > @@ -2631,12 +2635,10 @@ 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;
> > -	unsigned long flags;
> >  	pgoff_t end;
> >  
> >  	VM_BUG_ON_PAGE(is_huge_zero_page(head), head);
> > @@ -2697,9 +2699,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
> >  	unmap_page(head);
> >  	VM_BUG_ON_PAGE(compound_mapcount(head), head);
> >  
> > -	/* prevent PageLRU to go away from under us, and freeze lru stats */
> > -	spin_lock_irqsave(&pgdata->lru_lock, flags);
> > -
> > +	local_irq_disable();
> >  	if (mapping) {
> >  		XA_STATE(xas, &mapping->i_pages, page_index(head));
> >  
> > @@ -2729,7 +2729,7 @@ 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) };
> >  
> > @@ -2748,7 +2748,7 @@ 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);
> > +		local_irq_enable();
> >  		remap_page(head);
> >  		ret = -EBUSY;
> >  	}
> > 

^ permalink raw reply	[flat|nested] 35+ messages in thread

* Re: [PATCH v14 07/20] mm/thp: narrow lru locking
  2020-07-06 11:35     ` Matthew Wilcox
@ 2020-07-07  4:52       ` Hugh Dickins
  2020-07-09 14:02         ` Alex Shi
  2020-07-09 15:48         ` Kirill A. Shutemov
  2020-07-07 10:51       ` Alex Shi
  1 sibling, 2 replies; 35+ messages in thread
From: Hugh Dickins @ 2020-07-07  4:52 UTC (permalink / raw)
  To: Matthew Wilcox
  Cc: Alex Shi, Johannes Weiner, Kirill A. Shutemov, akpm, mgorman, tj,
	hughd, khlebnikov, daniel.m.jordan, yang.shi, lkp, linux-mm,
	linux-kernel, cgroups, shakeelb, iamjoonsoo.kim, richard.weiyang


[-- Attachment #1: Type: TEXT/PLAIN, Size: 7702 bytes --]

On Mon, 6 Jul 2020, Matthew Wilcox wrote:
> On Mon, Jul 06, 2020 at 05:15:09PM +0800, Alex Shi wrote:
> > Hi Kirill & Johannes & Matthew,

Adding Kirill, who was in patch's Cc list but not mail's Cc list.

I asked Alex to direct this one particularly to Kirill and Johannes
and Matthew because (and I regret that the commit message still does
not make this at all clear) this patch changes the lock ordering:
which for years has been lru_lock outside memcg move_lock outside
i_pages lock, but here inverted to lru_lock inside i_pages lock.

I don't see a strong reason to have them one way round or the other,
and think Alex is right that they can safely be reversed here: but
he doesn't actually give any reason for doing so (if cleanup, then
I think the cleanup should have been taken further), and no reason
for doing so as part of this series.

I had more need to know which way round they should go, when adding
lru_lock into mem_cgroup_move_account (inside or outside move_lock?):
but Alex's use of TestClearPageLRU appears to have successfully
eliminated the need for that; so I only need to know for the final
Doc patch in the series (credited to my name), where mm/rmap.c
documents the lock ordering.

I'm okay with leaving this patch in the series (and the final patch
currently documents this new order); but wondered if someone else
(especially Kirill or Johannes or Matthew) sees a reason against it?

And I have to admit that, in researching this, I discovered that
actually we unconsciously departed from the supposed lock ordering
years ago: back in 3.18's 8186eb6a799e, Johannes did a cleanup which
moved a clear_page_mlock() call to inside memcg move_lock, and in
principle clear_page_mlock() can take lru_lock. But we have never
seen a lockdep complaint about this, so I suspect that the page is
(almost?) always already isolated from lru when that is called,
and the issue therefore hypothetical.

My vote, for dispatch of the series, is to leave this patch in;
but cannot object if consensus were that it should be taken out.

Hugh

> > 
> > Would you like to give some comments or share your concern of this patchset,
> > specialy for THP part? 
> 
> I don't have the brain space to understand this patch set fully at
> the moment.  I'll note that the realtime folks are doing their best to
> stamp out users of local_irq_disable(), so they won't be pleased to see
> you adding a new one.  Also, you removed the comment explaining why the
> lock needed to be taken.
> 
> > Many Thanks
> > Alex
> > 
> > 在 2020/7/3 下午1:07, Alex Shi 写道:
> > > lru_lock and page cache xa_lock have no reason with current sequence,
> > > put them together isn't necessary. let's narrow the lru locking, but
> > > left the local_irq_disable to block interrupt re-entry and statistic update.
> > > 
> > > Hugh Dickins point: split_huge_page_to_list() was already silly,to be
> > > using the _irqsave variant: it's just been taking sleeping locks, so
> > > would already be broken if entered with interrupts enabled.
> > > so we can save passing flags argument down to __split_huge_page().
> > > 
> > > Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
> > > Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
> > > Cc: Hugh Dickins <hughd@google.com>
> > > Cc: Kirill A. Shutemov <kirill@shutemov.name>
> > > Cc: Andrea Arcangeli <aarcange@redhat.com>
> > > Cc: Johannes Weiner <hannes@cmpxchg.org>
> > > Cc: Matthew Wilcox <willy@infradead.org>
> > > Cc: Andrew Morton <akpm@linux-foundation.org>
> > > Cc: linux-mm@kvack.org
> > > Cc: linux-kernel@vger.kernel.org
> > > ---
> > >  mm/huge_memory.c | 24 ++++++++++++------------
> > >  1 file changed, 12 insertions(+), 12 deletions(-)
> > > 
> > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> > > index b18f21da4dac..607869330329 100644
> > > --- a/mm/huge_memory.c
> > > +++ b/mm/huge_memory.c
> > > @@ -2433,7 +2433,7 @@ 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);
> > > @@ -2442,8 +2442,6 @@ static void __split_huge_page(struct page *page, struct list_head *list,
> > >  	unsigned long offset = 0;
> > >  	int i;
> > >  
> > > -	lruvec = mem_cgroup_page_lruvec(head, pgdat);
> > > -
> > >  	/* complete memcg works before add pages to LRU */
> > >  	mem_cgroup_split_huge_fixup(head);
> > >  
> > > @@ -2455,6 +2453,11 @@ static void __split_huge_page(struct page *page, struct list_head *list,
> > >  		xa_lock(&swap_cache->i_pages);
> > >  	}
> > >  
> > > +	/* lock lru list/PageCompound, ref freezed by page_ref_freeze */
> > > +	spin_lock(&pgdat->lru_lock);
> > > +
> > > +	lruvec = mem_cgroup_page_lruvec(head, pgdat);
> > > +
> > >  	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 */
> > > @@ -2474,6 +2477,8 @@ static void __split_huge_page(struct page *page, struct list_head *list,
> > >  	}
> > >  
> > >  	ClearPageCompound(head);
> > > +	spin_unlock(&pgdat->lru_lock);
> > > +	/* Caller disabled irqs, so they are still disabled here */
> > >  
> > >  	split_page_owner(head, HPAGE_PMD_ORDER);
> > >  
> > > @@ -2491,8 +2496,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
> > >  		page_ref_add(head, 2);
> > >  		xa_unlock(&head->mapping->i_pages);
> > >  	}
> > > -
> > > -	spin_unlock_irqrestore(&pgdat->lru_lock, flags);
> > > +	local_irq_enable();
> > >  
> > >  	remap_page(head);
> > >  
> > > @@ -2631,12 +2635,10 @@ 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;
> > > -	unsigned long flags;
> > >  	pgoff_t end;
> > >  
> > >  	VM_BUG_ON_PAGE(is_huge_zero_page(head), head);
> > > @@ -2697,9 +2699,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
> > >  	unmap_page(head);
> > >  	VM_BUG_ON_PAGE(compound_mapcount(head), head);
> > >  
> > > -	/* prevent PageLRU to go away from under us, and freeze lru stats */
> > > -	spin_lock_irqsave(&pgdata->lru_lock, flags);
> > > -
> > > +	local_irq_disable();
> > >  	if (mapping) {
> > >  		XA_STATE(xas, &mapping->i_pages, page_index(head));
> > >  
> > > @@ -2729,7 +2729,7 @@ 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) };
> > >  
> > > @@ -2748,7 +2748,7 @@ 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);
> > > +		local_irq_enable();
> > >  		remap_page(head);
> > >  		ret = -EBUSY;
> > >  	}

^ permalink raw reply	[flat|nested] 35+ messages in thread

* Re: [PATCH v14 07/20] mm/thp: narrow lru locking
  2020-07-06 11:35     ` Matthew Wilcox
  2020-07-07  4:52       ` Hugh Dickins
@ 2020-07-07 10:51       ` Alex Shi
  1 sibling, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-07 10:51 UTC (permalink / raw)
  To: Matthew Wilcox
  Cc: akpm, mgorman, tj, hughd, khlebnikov, daniel.m.jordan, yang.shi,
	hannes, lkp, linux-mm, linux-kernel, cgroups, shakeelb,
	iamjoonsoo.kim, richard.weiyang



在 2020/7/6 下午7:35, Matthew Wilcox 写道:
>> Would you like to give some comments or share your concern of this patchset,
>> specialy for THP part? 
> I don't have the brain space to understand this patch set fully at
> the moment.  I'll note that the realtime folks are doing their best to
> stamp out users of local_irq_disable(), so they won't be pleased to see
> you adding a new one.  Also, you removed the comment explaining why the
> lock needed to be taken.
> 

Hi Matthew,

Thanks for response!

As to the local_irq_disable(), we could use local_irq_save(), but Hugh Dickin
suggest it's not necessary here. Also there are still much local_irq_disable()
in code. Hope it would be a big trouble for only one extra.

yes, The lru_lock comments is a bit early to remove, that should do in next 
TestClearPageLRU part. but since it would be changed soon. It won't be a critical
thing. Anyway I can change it to back in next version.

Thanks
Alex

^ permalink raw reply	[flat|nested] 35+ messages in thread

* Re: [PATCH v14 07/20] mm/thp: narrow lru locking
  2020-07-07  4:52       ` Hugh Dickins
@ 2020-07-09 14:02         ` Alex Shi
  2020-07-09 15:48         ` Kirill A. Shutemov
  1 sibling, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-09 14:02 UTC (permalink / raw)
  To: Hugh Dickins, Matthew Wilcox
  Cc: Johannes Weiner, Kirill A. Shutemov, akpm, mgorman, tj,
	khlebnikov, daniel.m.jordan, yang.shi, lkp, linux-mm,
	linux-kernel, cgroups, shakeelb, iamjoonsoo.kim, richard.weiyang



在 2020/7/7 下午12:52, Hugh Dickins 写道:
> My vote, for dispatch of the series, is to leave this patch in;
> but cannot object if consensus were that it should be taken out.

hi Johannes & Kirill,

What's your comments for this patch or others? I am ok to withdraw
this patch if no one like to give more comments on this.

Thanks
Alex

^ permalink raw reply	[flat|nested] 35+ messages in thread

* Re: [PATCH v14 07/20] mm/thp: narrow lru locking
  2020-07-07  4:52       ` Hugh Dickins
  2020-07-09 14:02         ` Alex Shi
@ 2020-07-09 15:48         ` Kirill A. Shutemov
  2020-07-10  8:23           ` Alex Shi
  1 sibling, 1 reply; 35+ messages in thread
From: Kirill A. Shutemov @ 2020-07-09 15:48 UTC (permalink / raw)
  To: Hugh Dickins
  Cc: Matthew Wilcox, Alex Shi, Johannes Weiner, akpm, mgorman, tj,
	khlebnikov, daniel.m.jordan, yang.shi, lkp, linux-mm,
	linux-kernel, cgroups, shakeelb, iamjoonsoo.kim, richard.weiyang

On Mon, Jul 06, 2020 at 09:52:34PM -0700, Hugh Dickins wrote:
> On Mon, 6 Jul 2020, Matthew Wilcox wrote:
> > On Mon, Jul 06, 2020 at 05:15:09PM +0800, Alex Shi wrote:
> > > Hi Kirill & Johannes & Matthew,
> 
> Adding Kirill, who was in patch's Cc list but not mail's Cc list.
> 
> I asked Alex to direct this one particularly to Kirill and Johannes
> and Matthew because (and I regret that the commit message still does
> not make this at all clear) this patch changes the lock ordering:
> which for years has been lru_lock outside memcg move_lock outside
> i_pages lock, but here inverted to lru_lock inside i_pages lock.
> 
> I don't see a strong reason to have them one way round or the other,
> and think Alex is right that they can safely be reversed here: but
> he doesn't actually give any reason for doing so (if cleanup, then
> I think the cleanup should have been taken further), and no reason
> for doing so as part of this series.

I've looked around and changing order of lru_lock wrt. i_pages lock seems
safe. I don't have much experience with memcg move_lock.

Alex, if you are going ahead with the patch, please document the locking
order. We have some locking orders listed at the beginning of filemap.c
and rmap.c.

local_irq_disable() also deserves a comment.

-- 
 Kirill A. Shutemov

^ permalink raw reply	[flat|nested] 35+ messages in thread

* Re: [PATCH v14 07/20] mm/thp: narrow lru locking
  2020-07-09 15:48         ` Kirill A. Shutemov
@ 2020-07-10  8:23           ` Alex Shi
       [not found]             ` <20200710112831.jrv4hzjzjqtxtc7u@box>
  0 siblings, 1 reply; 35+ messages in thread
From: Alex Shi @ 2020-07-10  8:23 UTC (permalink / raw)
  To: Kirill A. Shutemov, Hugh Dickins
  Cc: Matthew Wilcox, Johannes Weiner, akpm, mgorman, tj, khlebnikov,
	daniel.m.jordan, yang.shi, lkp, linux-mm, linux-kernel, cgroups,
	shakeelb, iamjoonsoo.kim, richard.weiyang



在 2020/7/9 下午11:48, Kirill A. Shutemov 写道:
> On Mon, Jul 06, 2020 at 09:52:34PM -0700, Hugh Dickins wrote:
>> On Mon, 6 Jul 2020, Matthew Wilcox wrote:
>>> On Mon, Jul 06, 2020 at 05:15:09PM +0800, Alex Shi wrote:
>>>> Hi Kirill & Johannes & Matthew,
>>
>> Adding Kirill, who was in patch's Cc list but not mail's Cc list.
>>
>> I asked Alex to direct this one particularly to Kirill and Johannes
>> and Matthew because (and I regret that the commit message still does
>> not make this at all clear) this patch changes the lock ordering:
>> which for years has been lru_lock outside memcg move_lock outside
>> i_pages lock, but here inverted to lru_lock inside i_pages lock.
>>
>> I don't see a strong reason to have them one way round or the other,
>> and think Alex is right that they can safely be reversed here: but
>> he doesn't actually give any reason for doing so (if cleanup, then
>> I think the cleanup should have been taken further), and no reason
>> for doing so as part of this series.
> 
> I've looked around and changing order of lru_lock wrt. i_pages lock seems
> safe. I don't have much experience with memcg move_lock.

Hi Kirill,

Thanks for response!
mem_cgroup_move_account(page) could not reach here since 2 blocks,
1, isolate_lru_page() before it will take page from lru, this compete for
   page reclaim path, list non-null.

2, try_lock_page in it, will guard split_huge_page(), !list.

> 
> Alex, if you are going ahead with the patch, please document the locking
> order. We have some locking orders listed at the beginning of filemap.c
> and rmap.c.

Thanks for reminder!
Hugh Dickins did this in above 2 files at the end of patchset, any comments?

diff --git a/mm/filemap.c b/mm/filemap.c
index f0ae9a6308cb..1b42aaae4d3e 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 d5e56be42f21..926d7d95dc1d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3057,7 +3057,7 @@ void __memcg_kmem_uncharge_page(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 5fe2dedce1fc..7fbc382e6f9e 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -28,12 +28,12 @@
  *           hugetlb_fault_mutex (hugetlbfs specific page fault mutex)
  *           anon_vma->rwsem
  *             mm->page_table_lock or pte_lock
- *               pgdat->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)
- *                   mem_cgroup_{begin,end}_page_stat (memcg->move_lock)
+ *                   lock_page_memcg move_lock (in __set_page_dirty_buffers)
  *                     i_pages lock (widely used)
+ *                       lock_page_lruvec_irq lruvec->lru_lock
  *                 inode->i_lock (in set_page_dirty's __mark_inode_dirty)
  *                 bdi.wb->list_lock (in set_page_dirty's __mark_inode_dirty)
  *                   sb_lock (within inode_lock in fs/fs-writeback.c)

> 
> local_irq_disable() also deserves a comment.
> 

yes, I will add a comment for this. Do you mind give reviewed-by for this patch?

Thanks
Alex

^ permalink raw reply	[flat|nested] 35+ messages in thread

* Re: [PATCH v14 07/20] mm/thp: narrow lru locking
       [not found]             ` <20200710112831.jrv4hzjzjqtxtc7u@box>
@ 2020-07-10 14:09               ` Alex Shi
  0 siblings, 0 replies; 35+ messages in thread
From: Alex Shi @ 2020-07-10 14:09 UTC (permalink / raw)
  To: Kirill A. Shutemov
  Cc: Hugh Dickins, Matthew Wilcox, Johannes Weiner, akpm, mgorman, tj,
	khlebnikov, daniel.m.jordan, yang.shi, lkp, linux-mm,
	linux-kernel, cgroups, shakeelb, iamjoonsoo.kim, richard.weiyang



在 2020/7/10 下午7:28, Kirill A. Shutemov 写道:
>>   *           hugetlb_fault_mutex (hugetlbfs specific page fault mutex)
>>   *           anon_vma->rwsem
>>   *             mm->page_table_lock or pte_lock
>> - *               pgdat->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)
>> - *                   mem_cgroup_{begin,end}_page_stat (memcg->move_lock)
>> + *                   lock_page_memcg move_lock (in __set_page_dirty_buffers)
>>   *                     i_pages lock (widely used)
>> + *                       lock_page_lruvec_irq lruvec->lru_lock
> I think it has to be
> 			    lruvec->lru_lock (in lock_page_lruvec_irq)

Good catch! I will update it in next version.
Thanks!

> 
> No?

> 
>>   *                 inode->i_lock (in set_page_dirty's __mark_inode_dirty)
>>   *                 bdi.wb->list_lock (in set_page_dirty's __mark_inode_dirty)
>>   *                   sb_lock (within inode_lock in fs/fs-writeback.c)
>>
>>> local_irq_disable() also deserves a comment.
>>>
>> yes, I will add a comment for this. Do you mind give reviewed-by for this patch?
> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

Thanks a lot! :)


^ permalink raw reply	[flat|nested] 35+ messages in thread

end of thread, back to index

Thread overview: 35+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-03  5:07 [PATCH v14 00/20] per memcg lru lock Alex Shi
2020-07-03  5:07 ` [PATCH v14 01/20] mm/vmscan: remove unnecessary lruvec adding Alex Shi
2020-07-03  5:07 ` [PATCH v14 02/20] mm/page_idle: no unlikely double check for idle page counting Alex Shi
2020-07-03  5:07 ` [PATCH v14 03/20] mm/compaction: correct the comments of compact_defer_shift Alex Shi
2020-07-03  5:07 ` [PATCH v14 04/20] mm/compaction: rename compact_deferred as compact_should_defer Alex Shi
2020-07-03  5:07 ` [PATCH v14 05/20] mm/thp: move lru_add_page_tail func to huge_memory.c Alex Shi
2020-07-03  5:07 ` [PATCH v14 06/20] mm/thp: clean up lru_add_page_tail Alex Shi
2020-07-03  5:07 ` [PATCH v14 07/20] mm/thp: narrow lru locking Alex Shi
2020-07-06  9:15   ` Alex Shi
2020-07-06 11:35     ` Matthew Wilcox
2020-07-07  4:52       ` Hugh Dickins
2020-07-09 14:02         ` Alex Shi
2020-07-09 15:48         ` Kirill A. Shutemov
2020-07-10  8:23           ` Alex Shi
     [not found]             ` <20200710112831.jrv4hzjzjqtxtc7u@box>
2020-07-10 14:09               ` Alex Shi
2020-07-07 10:51       ` Alex Shi
2020-07-03  5:07 ` [PATCH v14 08/20] mm/memcg: add debug checking in lock_page_memcg Alex Shi
2020-07-03  5:07 ` [PATCH v14 09/20] mm/swap: fold vm event PGROTATED into pagevec_move_tail_fn Alex Shi
2020-07-03  5:07 ` [PATCH v14 10/20] mm/lru: move lru_lock holding in func lru_note_cost_page Alex Shi
2020-07-03  5:07 ` [PATCH v14 11/20] mm/lru: move lock into lru_note_cost Alex Shi
2020-07-03  5:07 ` [PATCH v14 12/20] mm/lru: introduce TestClearPageLRU Alex Shi
2020-07-03  5:07 ` [PATCH v14 13/20] mm/compaction: do page isolation first in compaction Alex Shi
2020-07-03  5:07 ` [PATCH v14 14/20] mm/mlock: reorder isolation sequence during munlock Alex Shi
2020-07-03  5:07 ` [PATCH v14 15/20] mm/swap: serialize memcg changes during pagevec_lru_move_fn Alex Shi
2020-07-03  9:13   ` Konstantin Khlebnikov
2020-07-04 11:34     ` Alex Shi
2020-07-04 11:39       ` Matthew Wilcox
2020-07-04 13:12         ` Alex Shi
2020-07-04 13:33           ` Matthew Wilcox
2020-07-04 15:47             ` Alex Shi
2020-07-03  5:07 ` [PATCH v14 16/20] mm/lru: replace pgdat lru_lock with lruvec lock Alex Shi
2020-07-03  5:07 ` [PATCH v14 17/20] mm/lru: introduce the relock_page_lruvec function Alex Shi
2020-07-03  5:07 ` [PATCH v14 18/20] mm/vmscan: use relock for move_pages_to_lru Alex Shi
2020-07-03  5:07 ` [PATCH v14 19/20] mm/pgdat: remove pgdat lru_lock Alex Shi
2020-07-03  5:07 ` [PATCH v14 20/20] mm/lru: revise the comments of lru_lock Alex Shi

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