Messages in this thread | | | Date | Thu, 24 Sep 2009 11:28:38 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: page_migration question |
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On Sun, 20 Sep 2009 08:30:15 -0400 (EDT) Christoph Lameter <cl@linux-foundation.org> wrote:
> On Sun, 20 Sep 2009, Max Laier wrote: > > > I read Documentation/vm/page_migration but couldn't find the information I'm > > looking for. Specifically, what locks am I supposed to hold/not hold while > > calling migrate_prep() and migrate_pages()? Currently migrate_prep() seems to > > deadlock for reasons beyond me. Any help appreciated. > > No locks need to be held while calling migrate prep. The pages to be > migrated must have been isolated from the LRU and a refcount be taken for > migrate_pages to work. Look at the implementation of sys_migratepages and > sys_mbind and sys_movepages. >
If you find migrate_prep() hangs, please check your other cpus are available to run workqueue. It calls lru_add_drain_all()=>schedule_on_each_cpu().
Thanks, -Kame
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