Commit 6841c8e2 authored by KOSAKI Motohiro's avatar KOSAKI Motohiro Committed by Linus Torvalds

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: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Acked-by: default avatarGerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 02d21168
...@@ -299,7 +299,6 @@ void lru_add_drain(void) ...@@ -299,7 +299,6 @@ void lru_add_drain(void)
put_cpu(); put_cpu();
} }
#if defined(CONFIG_NUMA) || defined(CONFIG_UNEVICTABLE_LRU)
static void lru_add_drain_per_cpu(struct work_struct *dummy) static void lru_add_drain_per_cpu(struct work_struct *dummy)
{ {
lru_add_drain(); lru_add_drain();
...@@ -313,18 +312,6 @@ int lru_add_drain_all(void) ...@@ -313,18 +312,6 @@ int lru_add_drain_all(void)
return schedule_on_each_cpu(lru_add_drain_per_cpu); 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 * 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 * passed pages. If it fell to zero then remove the page from the LRU and
......
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