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From: Andrew Morton <akpm@linux-foundation.org>
To: aarcange@redhat.com, akpm@linux-foundation.org,
	alex.shi@linux.alibaba.com, alexander.h.duyck@linux.intel.com,
	aryabinin@virtuozzo.com, daniel.m.jordan@oracle.com,
	hannes@cmpxchg.org, hughd@google.com, iamjoonsoo.kim@lge.com,
	jannh@google.com, khlebnikov@yandex-team.ru,
	kirill.shutemov@linux.intel.com, kirill@shutemov.name,
	linux-mm@kvack.org, mgorman@techsingularity.net,
	mhocko@kernel.org, mhocko@suse.com, mika.penttila@nextfour.com,
	minchan@kernel.org, mm-commits@vger.kernel.org,
	richard.weiyang@gmail.com, rong.a.chen@intel.com,
	shakeelb@google.com, tglx@linutronix.de, tj@kernel.org,
	torvalds@linux-foundation.org, vbabka@suse.cz,
	vdavydov.dev@gmail.com, willy@infradead.org,
	yang.shi@linux.alibaba.com, ying.huang@intel.com
Subject: [patch 18/19] mm/lru: introduce relock_page_lruvec()
Date: Tue, 15 Dec 2020 12:34:33 -0800	[thread overview]
Message-ID: <20201215203433.gd0RZE7Fb%akpm@linux-foundation.org> (raw)
In-Reply-To: <20201215123253.954eca9a5ef4c0d52fd381fa@linux-foundation.org>

From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Subject: mm/lru: introduce relock_page_lruvec()

Add relock_page_lruvec() to replace repeated same code, no functional
change.

When testing for relock we can avoid the need for RCU locking if we simply
compare the page pgdat and memcg pointers versus those that the lruvec is
holding.  By doing this we can avoid the extra pointer walks and accesses
of the memory cgroup.

In addition we can avoid the checks entirely if lruvec is currently NULL.

[alex.shi@linux.alibaba.com: use page_memcg()]
  Link: https://lkml.kernel.org/r/66d8e79d-7ec6-bfbc-1c82-bf32db3ae5b7@linux.alibaba.com
Link: https://lkml.kernel.org/r/1604566549-62481-19-git-send-email-alex.shi@linux.alibaba.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
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: Tejun Heo <tj@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Chen, Rong A" <rong.a.chen@intel.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mika Penttilä <mika.penttila@nextfour.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/memcontrol.h |   52 +++++++++++++++++++++++++++++++++++
 mm/mlock.c                 |   11 -------
 mm/swap.c                  |   31 ++++----------------
 mm/vmscan.c                |   12 +-------
 4 files changed, 61 insertions(+), 45 deletions(-)

--- a/include/linux/memcontrol.h~mm-lru-introduce-the-relock_page_lruvec-function
+++ a/include/linux/memcontrol.h
@@ -485,6 +485,22 @@ out:
 
 struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *);
 
+static inline bool lruvec_holds_page_lru_lock(struct page *page,
+					      struct lruvec *lruvec)
+{
+	pg_data_t *pgdat = page_pgdat(page);
+	const struct mem_cgroup *memcg;
+	struct mem_cgroup_per_node *mz;
+
+	if (mem_cgroup_disabled())
+		return lruvec == &pgdat->__lruvec;
+
+	mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
+	memcg = page_memcg(page) ? : root_mem_cgroup;
+
+	return lruvec->pgdat == pgdat && mz->memcg == memcg;
+}
+
 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
 
 struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm);
@@ -984,6 +1000,14 @@ static inline struct lruvec *mem_cgroup_
 	return &pgdat->__lruvec;
 }
 
+static inline bool lruvec_holds_page_lru_lock(struct page *page,
+					      struct lruvec *lruvec)
+{
+	pg_data_t *pgdat = page_pgdat(page);
+
+	return lruvec == &pgdat->__lruvec;
+}
+
 static inline struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
 {
 	return NULL;
@@ -1354,6 +1378,34 @@ static inline void unlock_page_lruvec_ir
 	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)
+{
+	if (locked_lruvec) {
+		if (lruvec_holds_page_lru_lock(page, locked_lruvec))
+			return 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)
+{
+	if (locked_lruvec) {
+		if (lruvec_holds_page_lru_lock(page, locked_lruvec))
+			return 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);
--- a/mm/mlock.c~mm-lru-introduce-the-relock_page_lruvec-function
+++ a/mm/mlock.c
@@ -277,16 +277,7 @@ static void __munlock_pagevec(struct pag
 			 * so we can spare the get_page() here.
 			 */
 			if (TestClearPageLRU(page)) {
-				struct lruvec *new_lruvec;
-
-				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);
 				del_page_from_lru_list(page, lruvec,
 							page_lru(page));
 				continue;
--- a/mm/swap.c~mm-lru-introduce-the-relock_page_lruvec-function
+++ a/mm/swap.c
@@ -210,19 +210,12 @@ static void pagevec_lru_move_fn(struct p
 
 	for (i = 0; i < pagevec_count(pvec); i++) {
 		struct page *page = pvec->pages[i];
-		struct lruvec *new_lruvec;
 
 		/* block memcg migration during page moving between lru */
 		if (!TestClearPageLRU(page))
 			continue;
 
-		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);
-		}
-
+		lruvec = relock_page_lruvec_irqsave(page, lruvec, &flags);
 		(*move_fn)(page, lruvec);
 
 		SetPageLRU(page);
@@ -918,17 +911,12 @@ void release_pages(struct page **pages,
 		}
 
 		if (PageLRU(page)) {
-			struct lruvec *new_lruvec;
+			struct lruvec *prev_lruvec = lruvec;
 
-			new_lruvec = mem_cgroup_page_lruvec(page,
-							page_pgdat(page));
-			if (new_lruvec != lruvec) {
-				if (lruvec)
-					unlock_page_lruvec_irqrestore(lruvec,
-									flags);
+			lruvec = relock_page_lruvec_irqsave(page, lruvec,
+									&flags);
+			if (prev_lruvec != lruvec)
 				lock_batch = 0;
-				lruvec = lock_page_lruvec_irqsave(page, &flags);
-			}
 
 			VM_BUG_ON_PAGE(!PageLRU(page), page);
 			__ClearPageLRU(page);
@@ -1033,15 +1021,8 @@ void __pagevec_lru_add(struct pagevec *p
 
 	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);
-		}
 
+		lruvec = relock_page_lruvec_irqsave(page, lruvec, &flags);
 		__pagevec_lru_add_fn(page, lruvec);
 	}
 	if (lruvec)
--- a/mm/vmscan.c~mm-lru-introduce-the-relock_page_lruvec-function
+++ a/mm/vmscan.c
@@ -1883,8 +1883,7 @@ static unsigned noinline_for_stack move_
 		 * All pages were isolated from the same lruvec (and isolation
 		 * inhibits memcg migration).
 		 */
-		VM_BUG_ON_PAGE(mem_cgroup_page_lruvec(page, page_pgdat(page))
-							!= lruvec, page);
+		VM_BUG_ON_PAGE(!lruvec_holds_page_lru_lock(page, lruvec), page);
 		lru = page_lru(page);
 		nr_pages = thp_nr_pages(page);
 
@@ -4273,7 +4272,6 @@ void check_move_unevictable_pages(struct
 	for (i = 0; i < pvec->nr; i++) {
 		struct page *page = pvec->pages[i];
 		int nr_pages;
-		struct lruvec *new_lruvec;
 
 		if (PageTransTail(page))
 			continue;
@@ -4285,13 +4283,7 @@ void check_move_unevictable_pages(struct
 		if (!TestClearPageLRU(page))
 			continue;
 
-		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 (page_evictable(page) && PageUnevictable(page)) {
 			enum lru_list lru = page_lru_base_type(page);
 
_


  parent reply	other threads:[~2020-12-15 20:34 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-15 20:32 incoming Andrew Morton
2020-12-15 20:33 ` [patch 01/19] mm/thp: move lru_add_page_tail() to huge_memory.c Andrew Morton
2020-12-15 20:33 ` [patch 02/19] mm/thp: use head for head page in lru_add_page_tail() Andrew Morton
2020-12-15 20:33 ` [patch 03/19] mm/thp: simplify lru_add_page_tail() Andrew Morton
2020-12-15 20:33 ` [patch 04/19] mm/thp: narrow lru locking Andrew Morton
2020-12-15 20:33 ` [patch 05/19] mm/vmscan: remove unnecessary lruvec adding Andrew Morton
2020-12-15 20:33 ` [patch 06/19] mm/rmap: stop store reordering issue on page->mapping Andrew Morton
2020-12-15 20:33 ` [patch 07/19] mm: page_idle_get_page() does not need lru_lock Andrew Morton
2020-12-15 20:33 ` [patch 08/19] mm/memcg: add debug checking in lock_page_memcg Andrew Morton
2020-12-15 20:33 ` [patch 09/19] mm/swap.c: fold vm event PGROTATED into pagevec_move_tail_fn Andrew Morton
2020-12-15 20:34 ` [patch 11/19] mm/vmscan: remove lruvec reget in move_pages_to_lru Andrew Morton
2020-12-15 20:34 ` [patch 12/19] mm/mlock: remove lru_lock on TestClearPageMlocked Andrew Morton
2020-12-15 20:34 ` [patch 13/19] mm/mlock: remove __munlock_isolate_lru_page() Andrew Morton
2020-12-15 20:34 ` [patch 14/19] mm/lru: introduce TestClearPageLRU() Andrew Morton
2020-12-15 20:34 ` [patch 15/19] mm/compaction: do page isolation first in compaction Andrew Morton
2020-12-15 20:34 ` [patch 16/19] mm/swap.c: serialize memcg changes in pagevec_lru_move_fn Andrew Morton
2020-12-15 20:34 ` [patch 17/19] mm/lru: replace pgdat lru_lock with lruvec lock Andrew Morton
2020-12-15 20:34 ` Andrew Morton [this message]
2020-12-15 20:34 ` [patch 19/19] mm/lru: revise the comments of lru_lock Andrew Morton
2020-12-15 21:00 ` incoming Linus Torvalds
2020-12-15 22:20 ` [patch 01/19] mm/thp: move lru_add_page_tail() to huge_memory.c Andrew Morton
2020-12-15 22:20 ` [patch 02/19] mm/thp: use head for head page in lru_add_page_tail() Andrew Morton
2020-12-15 22:20 ` [patch 03/19] mm/thp: simplify lru_add_page_tail() Andrew Morton
2020-12-15 22:20 ` [patch 04/19] mm/thp: narrow lru locking Andrew Morton
2020-12-15 22:20 ` [patch 05/19] mm/vmscan: remove unnecessary lruvec adding Andrew Morton
2020-12-15 22:20 ` [patch 06/19] mm/rmap: stop store reordering issue on page->mapping Andrew Morton
2020-12-15 22:20 ` [patch 07/19] mm: page_idle_get_page() does not need lru_lock Andrew Morton
2020-12-15 22:20 ` [patch 08/19] mm/memcg: add debug checking in lock_page_memcg Andrew Morton
2020-12-15 22:20 ` [patch 09/19] mm/swap.c: fold vm event PGROTATED into pagevec_move_tail_fn Andrew Morton
2020-12-15 22:20 ` [patch 10/19] mm/lru: move lock into lru_note_cost Andrew Morton
2020-12-15 22:20 ` [patch 11/19] mm/vmscan: remove lruvec reget in move_pages_to_lru Andrew Morton
2020-12-15 22:20 ` [patch 12/19] mm/mlock: remove lru_lock on TestClearPageMlocked Andrew Morton
2020-12-15 22:21 ` [patch 13/19] mm/mlock: remove __munlock_isolate_lru_page() Andrew Morton
2020-12-15 22:21 ` [patch 14/19] mm/lru: introduce TestClearPageLRU() Andrew Morton
2020-12-15 22:21 ` [patch 15/19] mm/compaction: do page isolation first in compaction Andrew Morton
2020-12-15 22:21 ` [patch 16/19] mm/swap.c: serialize memcg changes in pagevec_lru_move_fn Andrew Morton
2020-12-15 22:21 ` [patch 17/19] mm/lru: replace pgdat lru_lock with lruvec lock Andrew Morton
2020-12-15 22:21 ` [patch 18/19] mm/lru: introduce relock_page_lruvec() Andrew Morton
2020-12-15 22:21 ` [patch 19/19] mm/lru: revise the comments of lru_lock Andrew Morton
2020-12-15 22:48 ` incoming Linus Torvalds
2020-12-15 22:49   ` incoming Linus Torvalds
2020-12-15 22:55     ` incoming Andrew Morton

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