forked from luck/tmp_suning_uos_patched
mm: migrate: one less atomic operation
migrate_page_move_mapping() drops a reference from the old page after unfreezing its counter. Both operations can be merged into a single atomic operation by directly unfreezing to one less reference. The same applies to migrate_huge_page_move_mapping(). Signed-off-by: Jacobo Giralt <jacobo.giralt@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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10
mm/migrate.c
10
mm/migrate.c
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@ -269,12 +269,12 @@ static int migrate_page_move_mapping(struct address_space *mapping,
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radix_tree_replace_slot(pslot, newpage);
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page_unfreeze_refs(page, expected_count);
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/*
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* Drop cache reference from old page.
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* Drop cache reference from old page by unfreezing
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* to one less reference.
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* We know this isn't the last reference.
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*/
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__put_page(page);
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page_unfreeze_refs(page, expected_count - 1);
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/*
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* If moved to a different zone then also account
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@ -334,9 +334,7 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,
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radix_tree_replace_slot(pslot, newpage);
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page_unfreeze_refs(page, expected_count);
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__put_page(page);
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page_unfreeze_refs(page, expected_count - 1);
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spin_unlock_irq(&mapping->tree_lock);
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return 0;
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