• KOSAKI Motohiro's avatar
    mm: remove UP version of lru_add_drain_all() · 6841c8e2
    KOSAKI Motohiro authored
    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>
    6841c8e2
swap.c 15.2 KB