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author | Hugh Dickins <hughd@google.com> | 2015-11-06 03:49:53 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-11-06 04:34:48 +0100 |
commit | 5c3f9a67371643b6faa987622bc1b67667bab848 (patch) | |
tree | 6c29472764822d11cd53509a7bc93aa3f6803e1c /mm/migrate.c | |
parent | mm: page migration trylock newpage at same level as oldpage (diff) | |
download | linux-5c3f9a67371643b6faa987622bc1b67667bab848.tar.xz linux-5c3f9a67371643b6faa987622bc1b67667bab848.zip |
mm: page migration remove_migration_ptes at lock+unlock level
Clean up page migration a little more by calling remove_migration_ptes()
from the same level, on success or on failure, from __unmap_and_move() or
from unmap_and_move_huge_page().
Don't reset page->mapping of a PageAnon old page in move_to_new_page(),
leave that to when the page is freed. Except for here in page migration,
it has been an invariant that a PageAnon (bit set in page->mapping) page
stays PageAnon until it is freed, and I think we're safer to keep to that.
And with the above rearrangement, it's necessary because zap_pte_range()
wants to identify whether a migration entry represents a file or an anon
page, to update the appropriate rss stats without waiting on it.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
-rw-r--r-- | mm/migrate.c | 34 |
1 files changed, 19 insertions, 15 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 6d7774ef0e6c..7b44ebdf2d26 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -722,7 +722,7 @@ static int fallback_migrate_page(struct address_space *mapping, * MIGRATEPAGE_SUCCESS - success */ static int move_to_new_page(struct page *newpage, struct page *page, - int page_was_mapped, enum migrate_mode mode) + enum migrate_mode mode) { struct address_space *mapping; int rc; @@ -755,19 +755,21 @@ static int move_to_new_page(struct page *newpage, struct page *page, * space which also has its own migratepage callback. This * is the most common path for page migration. */ - rc = mapping->a_ops->migratepage(mapping, - newpage, page, mode); + rc = mapping->a_ops->migratepage(mapping, newpage, page, mode); else rc = fallback_migrate_page(mapping, newpage, page, mode); - if (rc != MIGRATEPAGE_SUCCESS) { + /* + * When successful, old pagecache page->mapping must be cleared before + * page is freed; but stats require that PageAnon be left as PageAnon. + */ + if (rc == MIGRATEPAGE_SUCCESS) { + set_page_memcg(page, NULL); + if (!PageAnon(page)) + page->mapping = NULL; + } else { set_page_memcg(newpage, NULL); newpage->mapping = NULL; - } else { - set_page_memcg(page, NULL); - if (page_was_mapped) - remove_migration_ptes(page, newpage); - page->mapping = NULL; } return rc; } @@ -902,10 +904,11 @@ static int __unmap_and_move(struct page *page, struct page *newpage, } if (!page_mapped(page)) - rc = move_to_new_page(newpage, page, page_was_mapped, mode); + rc = move_to_new_page(newpage, page, mode); - if (rc && page_was_mapped) - remove_migration_ptes(page, page); + if (page_was_mapped) + remove_migration_ptes(page, + rc == MIGRATEPAGE_SUCCESS ? newpage : page); out_unlock_both: unlock_page(newpage); @@ -1066,10 +1069,11 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, } if (!page_mapped(hpage)) - rc = move_to_new_page(new_hpage, hpage, page_was_mapped, mode); + rc = move_to_new_page(new_hpage, hpage, mode); - if (rc != MIGRATEPAGE_SUCCESS && page_was_mapped) - remove_migration_ptes(hpage, hpage); + if (page_was_mapped) + remove_migration_ptes(hpage, + rc == MIGRATEPAGE_SUCCESS ? new_hpage : hpage); unlock_page(new_hpage); |