Messages in this thread Patch in this message | | | From | Mel Gorman <> | Subject | [PATCH 45/63] mm: numa: copy cpupid on page migration | Date | Fri, 27 Sep 2013 14:27:30 +0100 |
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From: Rik van Riel <riel@redhat.com>
After page migration, the new page has the nidpid unset. This makes every fault on a recently migrated page look like a first numa fault, leading to another page migration.
Copying over the nidpid at page migration time should prevent erroneous migrations of recently migrated pages.
Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> --- mm/migrate.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/mm/migrate.c b/mm/migrate.c index 6ff845f..1e1dbc9 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -439,6 +439,8 @@ int migrate_huge_page_move_mapping(struct address_space *mapping, */ void migrate_page_copy(struct page *newpage, struct page *page) { + int cpupid; + if (PageHuge(page) || PageTransHuge(page)) copy_huge_page(newpage, page); else @@ -475,6 +477,13 @@ void migrate_page_copy(struct page *newpage, struct page *page) __set_page_dirty_nobuffers(newpage); } + /* + * Copy NUMA information to the new page, to prevent over-eager + * future migrations of this same page. + */ + cpupid = page_cpupid_xchg_last(page, -1); + page_cpupid_xchg_last(newpage, cpupid); + mlock_migrate_page(newpage, page); ksm_migrate_page(newpage, page); /* -- 1.8.1.4
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