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Message-Id: <1579143909-156105-2-git-send-email-alex.shi@linux.alibaba.com>
Date: Thu, 16 Jan 2020 11:05:00 +0800
From: Alex Shi <alex.shi@...ux.alibaba.com>
To: cgroups@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-mm@...ck.org, akpm@...ux-foundation.org,
mgorman@...hsingularity.net, tj@...nel.org, hughd@...gle.com,
khlebnikov@...dex-team.ru, daniel.m.jordan@...cle.com,
yang.shi@...ux.alibaba.com, willy@...radead.org,
shakeelb@...gle.com, hannes@...xchg.org
Cc: yun.wang@...ux.alibaba.com
Subject: [PATCH v8 01/10] mm/vmscan: remove unnecessary lruvec adding
We don't have to add a freeable page into lru and then remove from it.
This change saves a couple of actions and makes the moving more clear.
The SetPageLRU needs to be kept here for list intergrity.
Otherwise:
#0 mave_pages_to_lru #1 release_pages
if (put_page_testzero())
if !put_page_testzero
!PageLRU //skip lru_lock
list_add(&page->lru,);
list_add(&page->lru,) //corrupt
Signed-off-by: Alex Shi <alex.shi@...ux.alibaba.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Johannes Weiner <hannes@...xchg.org>
Cc: Hugh Dickins <hughd@...gle.com>
Cc: yun.wang@...ux.alibaba.com
Cc: linux-mm@...ck.org
Cc: linux-kernel@...r.kernel.org
---
mm/vmscan.c | 32 +++++++++++++++++++++-----------
1 file changed, 21 insertions(+), 11 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 572fb17c6273..a270d32bdb94 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1852,26 +1852,29 @@ 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);
@@ -1879,9 +1882,16 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
spin_lock_irq(&pgdat->lru_lock);
} else
list_add(&page->lru, &pages_to_free);
- } else {
- nr_moved += nr_pages;
+ continue;
}
+
+ lruvec = mem_cgroup_page_lruvec(page, pgdat);
+ lru = page_lru(page);
+ nr_pages = hpage_nr_pages(page);
+
+ update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
+ list_add(&page->lru, &lruvec->lists[lru]);
+ nr_moved += nr_pages;
}
/*
--
1.8.3.1
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