From a25ede20bb12e1d2e2ad438dcab521da3b40c0b5 Mon Sep 17 00:00:00 2001
From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Date: Tue, 9 Dec 2008 13:14:16 -0800
Subject: [PATCH] mm: remove UP version of lru_add_drain_all()
Currently, lru_add_drain_all() has two version.
(1) use schedule_on_each_cpu()
(2) don't use schedule_on_each_cpu()
Gerald Schaefer reported it doesn't work well on SMP (not NUMA) S390
machine.
offline_pages() calls lru_add_drain_all() followed by drain_all_pages().
While drain_all_pages() works on each cpu, lru_add_drain_all() only runs
on the current cpu for architectures w/o CONFIG_NUMA. This let us run
into the BUG_ON(!PageBuddy(page)) in __offline_isolated_pages() during
memory hotplug stress test on s390. The page in question was still on the
pcp list, because of a race with lru_add_drain_all() and drain_all_pages()
on different cpus.
Actually, Almost machine has CONFIG_UNEVICTABLE_LRU=y. Then almost machine use
(1) version lru_add_drain_all although the machine is UP.
Then this ifdef is not valueable.
simple removing is better.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/swap.c | 13 -------------
1 file changed, 13 deletions(-)
diff --git a/mm/swap.c b/mm/swap.c
index 2881987603ebd..b135ec90cdeb9 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -299,7 +299,6 @@ void lru_add_drain(void)
put_cpu();
}
-#if defined(CONFIG_NUMA) || defined(CONFIG_UNEVICTABLE_LRU)
static void lru_add_drain_per_cpu(struct work_struct *dummy)
{
lru_add_drain();
@@ -313,18 +312,6 @@ int lru_add_drain_all(void)
return schedule_on_each_cpu(lru_add_drain_per_cpu);
}
-#else
-
-/*
- * Returns 0 for success
- */
-int lru_add_drain_all(void)
-{
- lru_add_drain();
- return 0;
-}
-#endif
-
/*
* Batched page_cache_release(). Decrement the reference count on all the
* passed pages. If it fell to zero then remove the page from the LRU and
--
2.39.5