diff mbox series

[v2,RT] mm/swap: use local lock in deactivate_page()

Message ID 20201127135456.8145-1-zqiu2000@126.com
State New
Headers show
Series [v2,RT] mm/swap: use local lock in deactivate_page() | expand

Commit Message

Zanxiong Qiu Nov. 27, 2020, 1:54 p.m. UTC 
From: Zanxiong Qiu <zqiu2000@126.com>

get_cpu_var() calls preempt_disable(), while on RT kernel,
pagevec_lru_move_fn() will call spinlock and might schedule
the context out and hence the schedule bug occurred, issue
is found on 5.4.70-rt40 and reproducable on 5.4.74-rt41.

32154a0abcc ("mm: Revert the DEFINE_PER_CPU_PAGEVEC implementation")
reverted the lock/unlock_swap_pvec function, however,
deactivate_page() part was missed at that time as it's newly
added in v5.4.

Signed-off-by: Zanxiong Qiu <zqiu2000@126.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
v1 -> v2: tweek the commit msg, remove call stack, add acked-by.

 mm/swap.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/mm/swap.c b/mm/swap.c
index cdb4f1fa3a48..463cac334fcf 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -666,12 +666,13 @@  void deactivate_file_page(struct page *page)
 void deactivate_page(struct page *page)
 {
 	if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) {
-		struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs);
+		struct pagevec *pvec = &get_locked_var(swapvec_lock,
+							lru_deactivate_pvecs);
 
 		get_page(page);
 		if (!pagevec_add(pvec, page) || PageCompound(page))
 			pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
-		put_cpu_var(lru_deactivate_pvecs);
+		put_locked_var(swapvec_lock, lru_deactivate_pvecs);
 	}
 }