Messages in this thread | | | From | Michel Lespinasse <> | Date | Sun, 27 Oct 2019 21:29:43 -0700 | Subject | Re: [Patch v2 1/2] lib/rbtree: set successor's parent unconditionally |
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Code looks fine, for both commits in this series. Please make sure to double check that lib/rbtree_test does not show any performance regressions, but assuming they don't, looks great !
Reviewed-By: Michel Lespinasse <walken@google.com>
On Sun, Oct 27, 2019 at 7:15 PM Wei Yang <richardw.yang@linux.intel.com> wrote: > > Both in Case 2 and 3, we exchange n and s. This mean no matter whether > child2 is NULL or not, successor's parent should be assigned to node's. > > This patch takes this step out to make it explicit and reduce the > ambiguity. > > Besides, this step reduces some symbol size like rb_erase(). > > KERN_CONFIG upstream patched > OPT_FOR_PERF 877 870 > OPT_FOR_SIZE 635 621 > > Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> > --- > include/linux/rbtree_augmented.h | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/include/linux/rbtree_augmented.h b/include/linux/rbtree_augmented.h > index fdd421b8d9ae..99c42e1a74b8 100644 > --- a/include/linux/rbtree_augmented.h > +++ b/include/linux/rbtree_augmented.h > @@ -283,14 +283,13 @@ __rb_erase_augmented(struct rb_node *node, struct rb_root *root, > __rb_change_child(node, successor, tmp, root); > > if (child2) { > - successor->__rb_parent_color = pc; > rb_set_parent_color(child2, parent, RB_BLACK); > rebalance = NULL; > } else { > unsigned long pc2 = successor->__rb_parent_color; > - successor->__rb_parent_color = pc; > rebalance = __rb_is_black(pc2) ? parent : NULL; > } > + successor->__rb_parent_color = pc; > tmp = successor; > } > > -- > 2.17.1 >
-- Michel "Walken" Lespinasse A program is never fully debugged until the last user dies.
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