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From: Alex Shi <alex.shi@linux.alibaba.com>
To: akpm@linux-foundation.org, mgorman@techsingularity.net,
	tj@kernel.org, hughd@google.com, khlebnikov@yandex-team.ru,
	daniel.m.jordan@oracle.com, yang.shi@linux.alibaba.com,
	willy@infradead.org, hannes@cmpxchg.org, lkp@intel.com,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	cgroups@vger.kernel.org, shakeelb@google.com,
	iamjoonsoo.kim@lge.com, richard.weiyang@gmail.com,
	kirill@shutemov.name, alexander.duyck@gmail.com,
	rong.a.chen@intel.com, Vladimir Davydov <vdavydov.dev@gmail.com>,
	Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH v17 00/21] per memcg lru lock
Date: Tue, 4 Aug 2020 16:36:51 +0800
Message-ID: <7622d74e-5884-4ee5-382d-78d6476db18a@linux.alibaba.com> (raw)
In-Reply-To: <1595681998-19193-1-git-send-email-alex.shi@linux.alibaba.com>

From e2918c8fa741442255a2f12659f95dae94fdfe5d Mon Sep 17 00:00:00 2001
From: Alex Shi <alex.shi@linux.alibaba.com>
Date: Sat, 1 Aug 2020 22:49:31 +0800
Subject: [PATCH 3/3] mm/swap.c: optimizing __pagevec_lru_add lru_lock

The current relock will unlock/lock lru_lock with every time lruvec
changes, so it would cause frequency relock if 2 memcgs are reading file
simultaneously.

This patch will record the involved lru_lock and only hold them once in
above scenario. That could reduce the lock contention.

Using per cpu data intead of local stack data to avoid repeatly
INIT_LIST_HEAD action.

[lkp@intel.com: found a build issue in the original patch, thanks]
Suggested-by: Konstantin Khlebnikov <koct9i@gmail.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 | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 51 insertions(+), 6 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index d88a6c650a7c..e227fec6983c 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -72,6 +72,27 @@ static DEFINE_PER_CPU(struct lru_pvecs, lru_pvecs) = {
 	.lock = INIT_LOCAL_LOCK(lock),
 };
 
+struct pvlvs {
+	struct list_head lists[PAGEVEC_SIZE];
+	struct lruvec *vecs[PAGEVEC_SIZE];
+};
+static DEFINE_PER_CPU(struct pvlvs, pvlvs);
+
+static int __init pvlvs_init(void) {
+	int i, cpu;
+	struct pvlvs *pvecs;
+
+	for (cpu = 0; cpu < NR_CPUS; cpu++) {
+		if (!cpu_possible(cpu))
+			continue;
+		pvecs = per_cpu_ptr(&pvlvs, cpu);
+		for (i = 0; i < PAGEVEC_SIZE; i++)
+			INIT_LIST_HEAD(&pvecs->lists[i]);
+	}
+	return 0;
+}
+subsys_initcall(pvlvs_init);
+
 /*
  * This path almost never happens for VM activity - pages are normally
  * freed via pagevecs.  But it gets used by networking.
@@ -963,18 +984,42 @@ static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec)
  */
 void __pagevec_lru_add(struct pagevec *pvec)
 {
-	int i;
+	int i, j, total = 0;
 	struct lruvec *lruvec = NULL;
 	unsigned long flags = 0;
+	struct page *page;
+	struct pvlvs *lvs = this_cpu_ptr(&pvlvs);
 
+	/* Sort the same lruvec pages on a list. */
 	for (i = 0; i < pagevec_count(pvec); i++) {
-		struct page *page = pvec->pages[i];
+		page = pvec->pages[i];
+		lruvec = mem_cgroup_page_lruvec(page, page_pgdat(page));
+
+		/* Try to find a same lruvec */
+		for (j = 0; j <= total; j++)
+			if (lruvec == lvs->vecs[j])
+				break;
+		/* A new lruvec */
+		if (j > total) {
+			lvs->vecs[total] = lruvec;
+			j = total;
+			total++;
+		}
 
-		lruvec = relock_page_lruvec_irqsave(page, lruvec, &flags);
-		__pagevec_lru_add_fn(page, lruvec);
+		list_add(&page->lru, &lvs->lists[j]);
 	}
-	if (lruvec)
-		unlock_page_lruvec_irqrestore(lruvec, flags);
+
+	for (i = 0; i < total; i++) {
+		spin_lock_irqsave(&lvs->vecs[i]->lru_lock, flags);
+		while (!list_empty(&lvs->lists[i])) {
+			page = lru_to_page(&lvs->lists[i]);
+			list_del(&page->lru);
+			__pagevec_lru_add_fn(page, lvs->vecs[i]);
+		}
+		spin_unlock_irqrestore(&lvs->vecs[i]->lru_lock, flags);
+		lvs->vecs[i] = NULL;
+	}
+
 	release_pages(pvec->pages, pvec->nr);
 	pagevec_reinit(pvec);
 }
-- 
1.8.3.1




  parent reply index

Thread overview: 102+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-25 12:59 Alex Shi
2020-07-25 12:59 ` [PATCH v17 01/21] mm/vmscan: remove unnecessary lruvec adding Alex Shi
2020-08-06  3:47   ` Alex Shi
2020-07-25 12:59 ` [PATCH v17 02/21] mm/page_idle: no unlikely double check for idle page counting Alex Shi
2020-07-25 12:59 ` [PATCH v17 03/21] mm/compaction: correct the comments of compact_defer_shift Alex Shi
2020-07-27 17:29   ` Alexander Duyck
2020-07-28 11:59     ` Alex Shi
2020-07-28 14:17       ` Alexander Duyck
2020-07-25 12:59 ` [PATCH v17 04/21] mm/compaction: rename compact_deferred as compact_should_defer Alex Shi
2020-07-25 12:59 ` [PATCH v17 05/21] mm/thp: move lru_add_page_tail func to huge_memory.c Alex Shi
2020-07-25 12:59 ` [PATCH v17 06/21] mm/thp: clean up lru_add_page_tail Alex Shi
2020-07-25 12:59 ` [PATCH v17 07/21] mm/thp: remove code path which never got into Alex Shi
2020-07-25 12:59 ` [PATCH v17 08/21] mm/thp: narrow lru locking Alex Shi
2020-07-25 12:59 ` [PATCH v17 09/21] mm/memcg: add debug checking in lock_page_memcg Alex Shi
2020-07-25 12:59 ` [PATCH v17 10/21] mm/swap: fold vm event PGROTATED into pagevec_move_tail_fn Alex Shi
2020-07-25 12:59 ` [PATCH v17 11/21] mm/lru: move lru_lock holding in func lru_note_cost_page Alex Shi
2020-08-05 21:18   ` Alexander Duyck
2020-07-25 12:59 ` [PATCH v17 12/21] mm/lru: move lock into lru_note_cost Alex Shi
2020-07-25 12:59 ` [PATCH v17 13/21] mm/lru: introduce TestClearPageLRU Alex Shi
2020-07-29  3:53   ` Alex Shi
2020-08-05 22:43     ` Alexander Duyck
2020-08-06  1:54       ` Alex Shi
2020-08-06 14:41         ` Alexander Duyck
2020-07-25 12:59 ` [PATCH v17 14/21] mm/compaction: do page isolation first in compaction Alex Shi
2020-08-04 21:35   ` Alexander Duyck
2020-08-06 18:38   ` Alexander Duyck
2020-08-07  3:24     ` Alex Shi
2020-08-07 14:51       ` Alexander Duyck
2020-08-10 13:10         ` Alex Shi
2020-08-10 14:41           ` Alexander Duyck
2020-08-11  8:22             ` Alex Shi
2020-08-11 14:47               ` Alexander Duyck
2020-08-12 11:43                 ` Alex Shi
2020-08-12 12:16                   ` Alex Shi
2020-08-12 16:51                   ` Alexander Duyck
2020-08-13  1:46                     ` Alex Shi
2020-08-13  2:17                       ` Alexander Duyck
2020-08-13  3:52                         ` Alex Shi
2020-08-13  4:02                       ` [RFC PATCH 0/3] " Alexander Duyck
2020-08-13  4:02                         ` [RFC PATCH 1/3] mm: Drop locked from isolate_migratepages_block Alexander Duyck
2020-08-13  6:56                           ` Alex Shi
2020-08-13 14:32                             ` Alexander Duyck
2020-08-14  7:25                               ` Alex Shi
2020-08-13  7:44                           ` Alex Shi
2020-08-13 14:26                             ` Alexander Duyck
2020-08-13  4:02                         ` [RFC PATCH 2/3] mm: Drop use of test_and_set_skip in favor of just setting skip Alexander Duyck
2020-08-14  7:19                           ` Alex Shi
2020-08-14 14:24                             ` Alexander Duyck
2020-08-14 21:15                               ` Alexander Duyck
2020-08-15  9:49                                 ` Alex Shi
2020-08-17 15:38                                   ` Alexander Duyck
2020-08-18  6:50                           ` Alex Shi
2020-08-13  4:02                         ` [RFC PATCH 3/3] mm: Identify compound pages sooner in isolate_migratepages_block Alexander Duyck
2020-08-14  7:20                           ` Alex Shi
2020-08-17 22:58   ` [PATCH v17 14/21] mm/compaction: do page isolation first in compaction Alexander Duyck
2020-07-25 12:59 ` [PATCH v17 15/21] mm/thp: add tail pages into lru anyway in split_huge_page() Alex Shi
2020-07-25 12:59 ` [PATCH v17 16/21] mm/swap: serialize memcg changes in pagevec_lru_move_fn Alex Shi
2020-07-25 12:59 ` [PATCH v17 17/21] mm/lru: replace pgdat lru_lock with lruvec lock Alex Shi
2020-07-27 23:34   ` Alexander Duyck
2020-07-28  7:15     ` Alex Shi
2020-07-28 11:19     ` Alex Shi
2020-07-28 14:54       ` Alexander Duyck
2020-07-29  1:00         ` Alex Shi
2020-07-29  1:27           ` Alexander Duyck
2020-07-29  2:27             ` Alex Shi
2020-07-28 15:39     ` Alex Shi
2020-07-28 15:55       ` Alexander Duyck
2020-07-29  0:48         ` Alex Shi
2020-07-29  3:54   ` Alex Shi
2020-08-06  7:41   ` Alex Shi
2020-07-25 12:59 ` [PATCH v17 18/21] mm/lru: introduce the relock_page_lruvec function Alex Shi
2020-07-29 17:52   ` Alexander Duyck
2020-07-30  6:08     ` Alex Shi
2020-07-31 14:20       ` Alexander Duyck
2020-07-31 21:14   ` [PATCH RFC] mm: Add function for testing if the current lruvec lock is valid alexander.h.duyck
2020-07-31 23:54     ` Alex Shi
2020-08-02 18:20       ` Alexander Duyck
2020-08-04  6:13         ` Alex Shi
2020-07-25 12:59 ` [PATCH v17 19/21] mm/vmscan: use relock for move_pages_to_lru Alex Shi
2020-08-03 22:49   ` Alexander Duyck
2020-08-04  6:23     ` Alex Shi
2020-07-25 12:59 ` [PATCH v17 20/21] mm/pgdat: remove pgdat lru_lock Alex Shi
2020-08-03 22:42   ` Alexander Duyck
2020-08-03 22:45     ` Alexander Duyck
2020-08-04  6:22       ` Alex Shi
2020-07-25 12:59 ` [PATCH v17 21/21] mm/lru: revise the comments of lru_lock Alex Shi
2020-08-03 22:37   ` Alexander Duyck
2020-08-04 10:04     ` Alex Shi
2020-08-04 14:29       ` Alexander Duyck
2020-08-06  1:39         ` Alex Shi
2020-08-06 16:27           ` Alexander Duyck
2020-07-27  5:40 ` [PATCH v17 00/21] per memcg lru lock Alex Shi
2020-07-29 14:49   ` Alex Shi
2020-07-29 18:06     ` Hugh Dickins
2020-07-30  2:16       ` Alex Shi
2020-08-03 15:07         ` Michal Hocko
2020-08-04  6:14           ` Alex Shi
2020-07-31 21:31 ` Alexander Duyck
2020-08-04  8:36 ` Alex Shi
2020-08-04  8:36 ` Alex Shi [this message]
2020-08-04  8:37 ` Alex Shi
2020-08-04  8:37 ` Alex Shi

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