Messages in this thread | | | Date | Tue, 19 Jul 2011 13:55:41 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] mm: remove useless rcu lock-unlock from mapping_tagged() |
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On Sun, Jul 17, 2011 at 03:35:23PM +0400, Konstantin Khlebnikov wrote: > radix_tree_tagged() is lockless, it does not require any protection.
Indeed. The radix_tree_root structure is a field in the address_space structure, so no protection is required to get at the field. If protection is required on the mapping pointer itself, that would have to happen in writeback_single_inode() and friends.
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> > --- > mm/page-writeback.c | 6 +----- > 1 files changed, 1 insertions(+), 5 deletions(-) > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index 31f6988..919b45e 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -1405,10 +1405,6 @@ EXPORT_SYMBOL(test_set_page_writeback); > */ > int mapping_tagged(struct address_space *mapping, int tag) > { > - int ret; > - rcu_read_lock(); > - ret = radix_tree_tagged(&mapping->page_tree, tag); > - rcu_read_unlock(); > - return ret; > + return radix_tree_tagged(&mapping->page_tree, tag); > } > EXPORT_SYMBOL(mapping_tagged); > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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