Messages in this thread Patch in this message |  | | | Date | Wed, 15 Apr 2009 09:32:10 +0200 | | From | Brice Goglin <> | | Subject | [PATCH] migration: only migrate_prep() once per move_pages() |
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migrate_prep() is fairly expensive (72us on 16-core barcelona 1.9GHz). Commit 3140a2273009c01c27d316f35ab76a37e105fdd8 improved move_pages() throughput by breaking it into chunks, but it also made migrate_prep() be called once per chunk (every 128pages or so) instead of once per move_pages().
This patch reverts to calling migrate_prep() only once per chunk as we did before 2.6.29. It is also a followup to commit 0aedadf91a70a11c4a3e7c7d99b21e5528af8d5d mm: move migrate_prep out from under mmap_sem
This improves migration throughput on the above machine from 600MB/s to 750MB/s.
Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
diff --git a/mm/migrate.c b/mm/migrate.c index 068655d..a2d3e83 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -820,7 +820,6 @@ static int do_move_page_to_node_array(struct mm_struct *mm, struct page_to_node *pp; LIST_HEAD(pagelist); - migrate_prep(); down_read(&mm->mmap_sem); /* @@ -907,6 +906,9 @@ static int do_pages_move(struct mm_struct *mm, struct task_struct *task, pm = (struct page_to_node *)__get_free_page(GFP_KERNEL); if (!pm) goto out; + + migrate_prep(); + /* * Store a chunk of page_to_node array in a page, * but keep the last one as a marker
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